yamaha 2 stroke outboard losing power. book 1 ページ 2018年11月9日 金曜日 午後5時49分. They each have 450 hours on them and until recently ran flawless. org/Hello, I have a '91 Yamaha ProV 150 on a Ranger 351V. I have replaced spark plugs, rebuilt the carb and fuel . I have attached the old vs new plugs and the overall view of the engine. The range and capacity of Honda 4-strokes are outstanding. A running internal combustion engine continually repeats a power cycle called: intake. *It appears to have jammed up in the splined joint between the male top of the main shaft and the female socket in the bottom of the cylinder block/power head. I believe that if you check fuel rail pressure at various RPMS under load you can confirm this condition. com is Your Only Source for OEM Manuals and Factory Authorized Reprints. Engine started fine, revs fine in neutral but once over 3000 revs in gear loses power under load. I have a 2002 175 HP HDPI 2 stroke Yamaha. Hi All, I have a 15hp (15fhm) 2 stroke and here is the issue. Yamaha 2stroke mid power marine outboard engines for sale. I have a question for you guys about a boat I recently purchased, a 2002 Boston Whaler, with a 2003 Yamaha 90hp 2 stroke Outboard. Get rid of this problem, and you may find that . It runs perfectly out of the water on muffs, and runs well in the water up to 1800 RPM, but bogs at about that point and wont go faster. Now regardless of whether it's on a garden strimmer, lawnmower or chainsaw, whenever we pull the throttle on a 2 stroke engine and get a bogged down sound it's almost always caused by an insufficient amount of fuel reaching the engine. -water in fuel getting past the water separating filter or no water separating filter and getting into the VST and injectors which causes them to clog. It is a Yamaha 4v 130 hp 2 stroke engine. About The Yamaha 150 Outboard Engine: Yamaha Marine released its new F150 four-stroke outboard engine to the market in 2004. The motor turns but doesn't seem to fire for quite a while. And their engines range from 2 to 250 hp. Our prices include shipping in the continental US, including the return of your core for credit. Here it goes, almost 50 miles out heading to SCI to get some rock fish. as put new plugs in and the engine RPM's will not go over 4000 RPM, if I push the throttle up to max it just bogs down and loses power. The first thing to check before anything else is the mixture screws. In this article, I will discuss the common problems and the solutions for Honda’s 4-stroke outboards. Yamaha outboard losing power stroke 2 About losing power outboard stroke 2 Yamaha View Propellers. The fuel air mixture screws on the side of the carburettor are marked H for High for the engines high speed adjustments and the L means Low for the engines low speed adjustments. The sale of outboard engines is 20% higher than they were in 2010. On a single revolution, there is a combined power and exhaust stroke followed by. Good working condition and easy to install. 9 LIT-18626-12-34 6DR-28199-38-E0 U6DR38E0. At the ramp, it's almost always hard to start, but on Saturday it was particularly troublesome. OWNER’S MANUAL F15 F20 LIT-18626-12-35 6AG-28199-3G-E0 6AG-9-3G-1E0. I have checked compression and found it has 130 on all 4 cylinders. Look Here For POWERHEAD KITS FOR U. Considering this, do outboard motors have hour meters? The meter can usually be found above the engine or somewhere around the steering area of the boat. It’s easy to do, and most times just involves a good visual and a fluid level inspection. 2 Liter Big Bore The Game Changing Four Stroke Series. After years of proven performance, our V6 4. V6 2-STROKE OUTBOARDS 4-STROKE MODELS ARE HERE. The next time your motor shuts down on your look to where the surface packs are for your electrical system (the part that powers the spark plugs) and spray WD40 or similar product on and around each item generously If it's an intermittent electrical short the lubricant will shut it down - and like magic your motor will regain full power. Plugs looked perfect but at certain RPM's the motor acted starved for fuel. Your outboard’s Power Trim and Tilt unit changes the outboard’s thrust angle during operation for maximum performance of both your outboard and your boat. About Yamaha losing power outboard stroke 2. Yamaha 1200R 66V PV 155 Hp Piston Ring Set. Just got done going through the same thing with a 115 johnson 4 stroke. YAMAHA 90 HP 2-STROKE 90 HP - Maritime Propulsion Yamaha 90HP 2 stroke intermittently losing power under load. After changing ignition coils, power packs, spark plugs. com/mike-chino Creative Commons — Attribution-ShareAlike 3. at points with WOT it seems to try every few mins I hear a slight rpm change. The engines store fuel in either a VST or an FSM. It runs on both sylinders, and starts very easily. I have an older Yamaha 15hp 2 stroke which bogs down at anything over 1/3 throttle. It is critical to mix oil with fuel in a 2-stroke engine. Some 2-stroke Yamaha 40 outboards, particularly older models from the 1980s and 1990s, had a mechanism that injected oil into the fuel rather than requiring it to be pre-mixed. 2 Stroke Outboard Fuel Mix Ratio 50:1 100:1? Finding the right mix for your outboard. 5 Yamaha 150 Outboard Problems You Should Know (Explained). I just got done fixing the very same issue with my 50hp 2-stroke Yamaha. 1984-1994 Yamaha 2hp 2-stroke Outboard Repair Manual. I do not get full speed/rpm out of it when I get it out of water. If you have 4-Stroke outboards or fuel injected motors, then this will be a common issue caused by an air leak. Can't get it in for service until jan 2 either so anyone got any ideas that may solve my problem. Yes, it does, doesn't it? Since these Yamaha thee cylinder motor were rather notorious for loose spark plug boots, why not see if that's the . I am surprised you have a problem with 5hp on a small inflateable. Classic symptoms of poor cable connections. 2 stroke 70hp loss of power 11-23-2019, 12:56 AM Have a 1999 2 stroke 70hp and when out today noticed got to 4000rpm and no more. Instant Download Manuals for Yamaha Outboard Engines 2. Popped the hood and changed the spark plugs. This 150hp engine was designed to satisfy the needs of the recreational boating community looking for a quieter engine with fuel-efficient power for small to mid-sized boats. Two Stroke Performance Tuning Chapter 3. By combining designs which Degner brought from MZ with Japanese technology in the field. Just happened first time running at 3800-4200 rpm for about 10 minutes started to lose power . We are NOT an Authorized Yamaha Dealer. When I accelerate I can feel the lack of power, and it struggles to get the boat (14ft RIB, total weight ca. This feature helps Yamaha’s new 4. Nov 26, 2017 #1 Hey guys, I am new to this group so any input is greatly. These engines are also getting more powerful. The lineups of Jul 05, 2016 · 2006 yamaha 50 hp 2 stroke losing power at full throttle. Power rated boat-owner customer satisfaction. 1996 Yamaha 115 Saltwater 2 Stroke S115TXRU I am having an issue with my 115 at full throttle, the engine dies or starts to die till I let off the throttle or if I don't catch it in time it will not recover resulting in a stall. He is complaining that it loses power . You may notice the engine losing prime or fuel randomly emptying when the primer bulb is bad. 10 Reasons Why A 2 Stroke Engine May Lose Power · mixture screws. #1 15hp strange loss of power 07-01-2014, 03:04 PM Hi All, I have a 15hp (15fhm) 2 stroke and here is the issue. Yamaha 225 TXR, TUR SHORT BLOCK POWER HEAD Re-Manufacured 2005 & Newer. 2-liter V6 Offshore outboards feature plasma-fused sleeveless cylinder walls, which are 60 percent harder than steel. About power 2 losing stroke outboard Yamaha. The motor then starts to stumble, runs rough and the RPMs fall off to about 2000. Watch our Yamaha Outboard Fuel Pump Issues video above — in which we guide you through an outboard's fuel system — to troubleshoot possible issues that may be causing fuel pump problems. A quick safety warning here – even if your boat seems to be operating just fine, operating with a spun prop can risk damaging your propeller irreparably. Though I had a 80 yamaha 4 stroke and those plugs were 40 dollars. The hole shot to planing used to take about 3 to 6 seconds depending on extra weight (fuel, passengers). The reason the machine will sit idling with no problem is because it is getting enough fuel for the level of engine speed required, however as soon as we try to increase that speed where we need more fuel there. The engine has an external flush port, plus built-in carry handles and rest pads. PARTS PACKAGE KITS FOR REBUILDING POWERHEADS. You might find corroded fuel connections. V-6, Carb, OX-66, 2-stroke Not rated yet. A Yamaha two stroke engine with a 50 or below horsepower uses a battery that contains 245 cold cranking amps at zero degrees Fahrenheit and 323 marine ranking amps at 32 degrees Fahrenheit. NOTE: Although we're using a Yamaha 250HP motor as an example, the fuel system will be very similar on any modern outboard, regardless of brand or model. The rest of the time the motor ran like top. 2003 Yamaha 90hp 2 stroke power loss, runs sluggish. The kit I have is for a Mercury. So that motor of yours has finally terminated itself? No need to worry, we have you covered. I have a 2004 Yamaha 115 HP 2 stroke saltwater series outboard. I've had this boat for about 2 years and have been happy. 2 liter big-bore V6 Offshore Outboard to deliver awesome hole shot and mid-range acceleration you have to feel to believe. Here is some basic information about each type: 2-cycle: This kind of Yamaha outboard powerhead runs with two cycles. Mixture Screws The first thing to check before anything else is the mixture screws. Works with all Yamaha 4-stroke models only, including Yamaha gasoline generators and pumps. 11 dollars later and problem solved. What is Yamaha 2 stroke outboard losing power As for the original post, as other have pointed out the 9 pound tank mentioned is more likely a 90 lb tank. ski's etc high fuel consumption good power, 43% prop slip and are losing up to 35%. It's a good thing since we had to race for cover twice from thunderstorms. A downloadable Yamaha 40hp outboard repair manual is a digitally transmitted instruction book that details the procedures of maintaining and repairing an outboard motor. If you think a spun prop is the reason your outboard motor is losing power, and your boat is unable to produce top speed, it is time you head to local marine mechanic for repair. Tip: Yamaha four-stroke outboard timing belts and HPDI® two-stroke outboard high-pressure fuel pump belts are cogged and Kevlar®-impregnated, . In the absence of the "electronic adjust" , general rule of thumb on my outboards was 1/2 X 1/2 per 5,000 ft of elevation. Spring is well underway and we are about to roll into summer. Some manufacturers, like Yamaha, suggest changing the water-pump Being two-stroke engines, they have no crankcase oil to change, . What happens if you put too much oil in a 2-stroke outboard? Excess oil can produce a smoky exhaust, oil leaking out of the muffler, and sometimes loss of power. The motor stalled, when started again the motor idled no issue, when put into gear and increasing the throttle t … read more. Yamaha has the parts catalogs up on their website (USA-Canada Market Area Motors Only) We have posted the link here for your convenience: Parts Catalogs Keep the trim rams fully retracted when not in use to prevent corrosion build-up. Troubleshooting 2 Stroke Ignition Problems; Troubleshooting 2 Stroke Ignition Problems. Rebuilt Yamaha Outboard Powerheads. On the Outboards you do not have that. Read this manual carefully before operating this outboard motor. Author Note: If you find plenty of fuel and your tank isn't leaking, then your next move is to inspect the fuel filter. I have a yamaha 115 hp 2 stroke outboard (115TRC ). Outboard Two Strokes should have a compression of anywhere between 90 PSI to . The oil leak is caused by the secondary reservior spilling over when it is tilted. The Yamaha F115 is a great 4-stroke outboard motor which 2. Thread starter BMXben; Start date Nov 26, 2017; B. Yamaha 90HP 2 stroke intermittently losing power under load. Service during regularly scheduled annual checkups or every 100 hours of operation is recommended for outboards in normal recreational usage, annually or 500 hours for fishing guides or multiple-trip-per-week recreational fishermen. Still sounds okay but just no power. More Canadians than ever are enjoying life on the water. Whilst I am always happy to try and help in diagnosis, it can be very hard to do so over the phone. A stroke is the movement of the piston in one direction, moving the piston from the top to the bottom of the cylinder is one stroke. Will try new plugs tomorrow (current only 2 months old). That means larger cylinder bores for increased displacement, resulting in more power and torque, without increasing outer cylinder dimensions. I have a haines hunter 530 with a 2002 yamaha v4 2 stroke outboard. Two Stroke Performance Tuning Fig. Here are 10 reasons and fixes to help prevent lack of fuel to a 2-stroke engine. Also, at a battery switch if the motor . Yamaha engines come from the factory with NGK brand spark Check the condition of the propeller if the engine starts but loses power. Has forward controls, power trim and tilt, electric start and oil injection. Yamaha has the parts catalogs up on their website (USA-Canada Market Area Motors Only) We have posted the link here for your convenience:. The cure is a matter of diagnosing and cleaning the . Things that have been suggested from bar stool Merc techs: fuel filter, fuel pump, fuel line/primer ball. Best-in-Class Fuel Efficiency: Yamaha’s 300hp V6 Offshore outboard has up to 17% better long-range fuel economy at 3500 rpm than other 300hp 4 stroke outboards. My next step is to grab an inline spark tester and check for spark to try and Eliminate as many issues as I can. Some of the new or rebuilt Yamaha outboard powerheads are 2-cycle models and others are 4-cycle models. I was having two issues actually. T hese kits contain most all the parts you will commonly need to complete the overhaul of your outboard's powerhead. 10 Reasons Why A 2 Stroke Engine May Lose Power. Replaces most Yamaha 90 Degree V6 2-Stroke up to 200 HP, and some inline 4 cyl. Yamaha, Suzuki, Honda and Mercury four-stroke outboards are the most susceptible. LOOK HERE FOR 4-STROKE APPLICATIONS. YAMAHA 90 HP 2-STROKE 90 HP vs VOLVO PENTA MD32A 105. 115 yamaha 4 stroke loses power at wide open. Anyone got any advice on how to sort a seized*Yamaha 5hp 2 stroke outboard? After a couple weeks of not being used, I can't turn the engine. Feb 26, 2014 #2 Re: Yamaha Outboard losing power. The only things that I did differently was to run all the gas out of the motor after the last trip and I didn't tilt it all the way up afterwards. OWNER’S MANUAL F25 T25 LIT-18626-12-36 6BP-28199-3E-E0 6BP-9-3E-1E0. Nov 26, 2017 #1 Hey guys, I am new to this group so any input is greatly appreciated. I can run the outboard for 2-3 hours with no loss of speed or power, but if I shut the motor down or if it runs out of gas, I will have to wait for 20-30 minutes before it will restart. Joined Sep 7, 2008 Messages 8,078. No problems until today, won''t get above 3200 RPM, but it''ll surge every once in awhile. Today we ran about 10 miles without a hint of motor trouble. Yamaha 8hp 2 Stroke Type: Hanging Type of control: Tiller Boat transom height (cm): 381 Grade: with propeller Starter Type: Manual Weight (kg): 28 This modelis a proven performer, light enough to be a great portable engine but with enough power to push a small fishing boat or tender at a pleasing cruising. This 90hp 4-stroke EFI features the same valve train architecture as Verado. Hi everyone, I'm new to this page as well as being pretty new to boat engines as well. However, there are some common issues with the engine. I have a 90HP Yamaha 2-Stroke on the back of my HPX-V 17. About stroke 2 outboard Yamaha losing power. "Stowing a motor vertical is just fine for a 2-stroke motor, because a 2-stroke outboard has its oil mixed in the gas, so there isn't an issue. Even if the old ones still look good, change them. Preference is given to tested products, proven brands. That is why with outboard engines in high-use applications, 2-stroke . book Page 1 Tuesday, November 27, 2018 2:08 PM. While not ideal, these issues can be fixed by simply replacing the fuel in the tank with properly mixed fuel. Outboards were mentioned (Yamaha owners reported experiencing the least problems), though responses weren't quantified. 2 Stroke Versus 4 Stroke Outboard Boat Motor Comparison. Just had 200 hour maintentance done in Apr 2008. At low RPM there are no issues. Rebuilt Powerheads for Yamaha Outboards. 2-Strokes on the other hand, that is a different story!. The small gain in horse power will usually cause premature failure of your alloy piston. I recently brought my boat into . Re: 2004 Yamaha 150 Two-Stroke Power Loss. " Date Although Yamaha created a kit to try to correct these problems, it has not issued any technical service bulletins or recalls regarding the motors. 3 honda 4 stroke and a 4HP evinrude on a similar size dinghy. 1989 YAMAHA OUTBOARD 2 HP 1 CYL. Selecting an expensive oil for two-stroke outboard engines, you can get a boost in power for a few horses. 9HP 15HP 20 HP 25 30 40 48 50 55 60 70 75 90 100 115 130 150 200 225 250 HP 4-Stroke & 2 Stroke Models. Brand new spark plugs, brand new ignition coils, brand new - Answered by a verified Marine Mechanic We use cookies to give you the best possible experience on our website. (43CC) 2-STROKE, this Service Manual has detailed illustrations as well as step by step instructions,It is 100 percents complete and intact. Like mentioned, I have 1996 (?) 25QEO, deristricted to full 40 hp, its loosing power when gets warm. At initial start-up, everything runs fine. It is run daily and suddenly lost power. I just rebuilt the complete motor(new crank, bearings, shims, and top end). The engine ran great the first few times I had it out, but always seemed sluggish, I was getting 4600 rpm and 36 mph at WOT, but it would take a while to get up. The Yamaha replacement parts listed on this site are aftermarket parts. Am i losing much, eg, power, longevity etc. DOWNLOAD Yamaha 40hp (40 hp) Repair Manual. Engine will start up fine 1st pull Engine will idle fine Go into gear and idle fine In idle will rev up fine However under load wont go past half power. The basis of the engine is a four-in-line, 1732cc powerhead, – the largest displacement engine in the 90hp 4-stroke class – dual overhead cam engine that provides excellent low-end power. Reason for the Problem: Fault in the fuel line connecting Yamaha outboard motor with the fuel tank. Failure of the Oil to Lubricate the Cylinders. Changed the plugs, added some dry gas ( thought I might have gotten some bad gas). to be sure,next time it happens take a spark pluug out and see if its wet with fuel,or dry. Engine suddenly dies and turns off. Like the title says, 1999 50 HP Merc 2-stroke losing power at wide open throttle. pump is out of whack and delivers too much oil, the engine will smoke, run rough, and lose power. 1996 Yamaha 115 Saltwater 2 Stroke S115TXRU no power, loss of. Yamaha Outboard Parts Lower Units 2-Stroke 4-Stroke EFI Enduro ETXD HPDI Jet OX66 VMAX V4 V6 V8 170. Remove, clean and reattach the battery cables at both ends. Yamaha Outboard Power Loss Forum Topics. Last year was the first year J. Inner Peace by Mike Chino https://soundcloud. You are going to have to run a smaller diameter and pitch to keep the RPM's up to burn the excess fuel. Yamaha advertised its outboard motors as "high-power" engines with "unmatched reliability and durability. The engine ran great the first few times I had it out, but always seemed sluggish, I was getting 4600 rpm and 36 mph at WOT, but it would take a while to get up there, it didn't seem to be very responsive. The Yamaha Engine Meter helps you keep track of your engine's operating hours, as well as engine RPM. In this video I will be installing a new CCMS (Chris Carson Marine Services) composite reed valve and crankcase stuffer kit. Started easily, idled well, got on plane faster, but still. Engine will start up fine 1st pull. Bad spark plugs cause loss of engine power, decreased acceleration, or problems starting the engine. book 1 ページ 2018年11月8日 木曜日 午前9時35分. I have an older Yamaha 25hp 2-stroke. It's a 2010 TLR Yamaha 2 stroke. Corroded or fouled spark plug wires can also cause the outboard motor to sputter or lose power. One of the most common Yamaha 115 4-stroke problems is a bad . also just Friday the 115 would not produce more than 4,000 RPM. 5 - 250 HP 2-Stroke, 1997-1999"; Seloc Marine, 2007 Warnings Never operate your outboard out of the water unless you provide a source of cooling water. issue: outboard motor (75hp mercury tracker -- 3 cylinder, 2 cycle) runs well for several mins at full throttle, then dies/loses power. The Yamaha Owner’s Manual suggests you perform standard maintenance on your power tilt and trim after the first 20 hours, then every 100 hours or annually for the life of the motor. where is the water intake vents on a 1975 15hp 2 stroke outboard. Once I go up to cruising RPM 2800 - 3200 or higher and the bow rises prior to going on plane the power to the motor momentarily dies, as soon as the bow drops again, it immediately returns to same RPM. To improve the position, it is necessary to choose the oil for two-stroke outboard engines carefully. Honda happens to be the first company to provide 4 stroke motors in America. Pumped primer also when underway to see if. I have a 1998 Yamaha 130 HP 2 stroke. It’s electro-hydraulic, meaning an electric pump moves hydraulic fluid upon command from the operator, tilting the. Had visual check but nothing jumping out. About power 2 outboard stroke losing Yamaha. Hello, I have a '91 Yamaha ProV 150 on a Ranger 351V. All of these are impractical on water cooled outboard. We headed out of the Pensacola Beach Pass to do some heavy offshore fishing for Amberjack when Murphy's Law struck our Yamaha outboard boat motor. Today the average is 58 horsepower. Remanufactured Yamaha powerheads come with a one-year limited warranty. Yes this will cause it to lose power if it is not getting enough gas. After about a month ago, after a day of fishing, I was headed back to th. Search: Yamaha 2 stroke outboard losing power. We have available a selection of Remanufactured Powerheads for Yamaha outboards. Ok i have a 1990 oil injected 90 yamaha cleaned all 3 carbs pilot and main pulled the pilot screws cleaned all that set them at 2 turns out . While in 2010, the average engine power was 46 horsepower. I have a 1998 Yamaha 130 HP 2 stroke. What I know Primer ball in the fuel line seems to be holding firm. The Boating Forum - Need help please! Yamaha 150 V6 2-stroke, losing power? - Hi guys, Ok, here's the story. hi i have a yamaha 55 2 stroke on my lencraft, the outboard is from around 1992 the model number is 663 , 55 bed L. Modifications could make the motor unfit or unsafe to use. they are specifically written for the do-it-yourself-er as well as the experienced mechanic. It is also the heaviest of all the 90hp engines we tested, at 181kg. and I had many problems with it failing to start etc. (70cc) 2-stroke 1990 1994, 4 hp 1 cyl. 2006 yamaha 50 hp 2 stroke losing power at full throttle. The temp and oil alarms are flashing (Both flash twice and then. 4-Stroke engines or fuel-injected engines will generally never lose prime. That said, there are parts of the system that I still attend to on a. Hi - any clues as to where to find power curves/data for Yamaha 200hp 2-strokes? or any representative 200hp 2-stroke? I cannot find anything online in the manufacturers site(s). Initially, boaters were attracted to their power, efficiency and intelligent design. This is the Highly Detailed factory service repair manual for the1989 YAMAHA OUTBOARD 2 HP 1 CYL. Contemporary two-stroke technology was introduced initially to Suzuki, and later to Yamaha in Japan when Ernst Degner defected from East Germany to join Suzuki. 2-liter outboards have been offshore favorites for more than a decade. About 2 outboard losing power stroke Yamaha. Power Tilt and Trim Maintenance Makes a. Make sure you have good air flow through the cover. If the primer bulb is cracked or dry rotted it will need to be replaced. Wondering if anyone has any feedback or direction to the potential issue. 00 (Contact us for chrome bore This will cause loss of power, hard starting and unsatisfactory slow speed performance due to loss of compression. Core value is primarily based on the condition of your block and crankshaft. We have a 2006 Parker 2520 with twin 150 Yamaha 4 strokes. 2 stroke fuel oil mix chart In this guide we step through the why it's vital to get the right 2 stroke fuel oil mix and some methods to work out which ratio to use for your outboard. These manuals vary with respect to the manufacturer and in regards to the models of boat engines produced by the manufacturer. 2 LITER BIG BORE DISPLACEMENT: Yamaha’s 4. 2-liters have become known for something perhaps even more valuable offshore—reliability. Up until today has been going well. Has new plugs, fuel lines all seem ok, just seems it wants to kick on but splutters and drops back. Yamaha & Suzuki Outboards Yamaha 90HP 2 stroke intermittently losing power under load. I'm having an issue with my 2003 Yamaha 115hp 4-stroke (1030 hours). I have an older Merc 2 stroke that I just purchased . Jul 05, 2016 · 2006 yamaha 50 hp 2 stroke losing power at full throttle. just looking for a ball-park rev/hp relationship. Power Trim & Tilt » Yamaha Maintenance Matters. In turn, in order to compete with the 2-stroke performance, 4-stroke outboards needed to lose some weight. Outboard Battery Requirements for Yamaha. What kind of engine is it (2-stroke, HPDI, 4-stroke)? Sounds like a fuel restriction but also could be down one cylinder. Yamaha Marine builds the best 2- and 4-stroke motors, according to a new "engine performance index" compiled by J. Traditional speed boat engines use a battery to kick start the engine and power boat accessories. Still have the problem after doing that. Yamaha 90HP 2 stroke intermittently losing power under load. Sorry no outboard motors in this range About Wynnum Marine. "Yamaha Outboards Repair Manual 2. Have a 1999 2 stroke 70hp and when out today noticed got to 4000rpm and no more. Didn't stall at all just lack of power. Joined Nov 26, 2017 Messages 4. 1987 – 1992 Yamaha 30hp 2 stroke Outboard Repair Manual Model : 30ELD, 30ELF, 30ELG, 30ELH, 30ELRP, 30ELRQ, 30MLHQ, 30MSHP, 30MSHQ, 30OLF, 30OSF, 30SD, 30SF, 30SG, 30SH. Yamaha Outboard Power Loss. If the rated horsepower capacity of the boat is unknown, consult the dealer or boat man-ufacturer. LOOK HERE FOR 2-STROKE APPLICATIONS. Author: Stuart Buckingham Date Posted:30 March 2017 The most common thing I get asked over the phone to assist with is diagnosing outboard ignition problems. Hi all, I havent been on for yonks so i thought this would be a great opportunity to ask for your advice on the yamaha 2-strokes. at points with WOT it seems to try. The rated power of the outboard should be equal to or less than the rated horsepower capacity of the boat. It's a 90 hp mariner 2003 outboard 3 cylinder 2 stroke. However under load wont go past half power. All the cylinders have pretty similar compressions, tried 2 different tanks of fuel so don't think it is the actual fuel or the fuel lines but will get some additive and try that. Thanks to modern technology, today's 4-stroke motors are comparable to 2-strokes in their size, speed, portability and acceleration. I have come across a Yamaha 25hp CV 2-Stroke outboard to put on my tinny, but, as this is the "Customer Version" or something. Yamaha 115 4 Stroke Short Block Power Head Remanufactured 2000 & Newer $2915. 2 Stroke vs 4 Stroke Outboard Motors: A Side by Side Comparison. Finishing with tips on how to mix two stroke efficiently and safely. Increasing the capacity of two-stroke outboard motors. I'd bet he's losing power on one cylinder because of a plugged carb . Two-stroke or four-stroke refers to the number of strokes the piston makes in the cylinder to complete one power cycle. 2-stroke versus 4-stroke Yamaha powerheads. Although the American Motors Company made about 25 gas powered outboards before 1900, it took a Yale engineering student, Cameron Waterman, to make a commercially feasible outboard. Bear with me, and maybe Boat Doc can expalin better, but we worked on my buddies 115 2-stroke for quite awhile until it got fixed.