- Yamaha 2 stroke mercury outboard compression chart yet the compression was good and the leakage rate above 70%. on a 4 stroke it is a teat on a boar hog. On a 4 stroke engine, most mechanics and dealers will perform a leak down test, to see how much pressure escapes over a set period of time. on two stroke a compression test is quick easy and painless. Dec 12, 2013 · considering a 90 hp mercury/ mariner 2 stroke, but the listed comp figures seem low to me at 100 lbs, supposedly all even though, are these numbers too low for this year motor, or is it in the "normal" range for a used '99? Dec 12, 2013 · Re: 1999 90 hp 2 stroke compression numbers, My service manual, OEM Merc/Mariner PN 90-830234R3 publication date Dec. 2002 25hp 2 stroke Jan 4, 2022 · Increasing Compression On A Two-Stroke Outboard. Removed power head and soaked in mystery oil for two weeks and broke pistons free. Middle and lower cylinder are just Apr 29, 2019 · Compression Test on a Mercury Salt Water series 2 stroke on a 2002 Pro-Line Nov 27, 2012 · oil in a two stroke for compression testing is a waste of time and oil. 9's, basically the same motor as the 15, that have over 2000 hours each), but have had "zero" trouble with any of them (the 9. Looking for some input on compression readings as this is my first time dealing with a Yamaha outboard. but on one cylinder the pressure in the screwed in Feb 25, 2021 · I ran a compression test with a lisle gauge. 4 stroke engines make compression differently than 2 stroke engines, but the principle is the same. Product names, coloring and graphics may also differ. partzilla. It's a 1999 Johnson non-fitch 2 stroke and I only used the boat just over a year. This is measured in psi, or pounds per square inch, and we refer to it as the compression reading. I see 155 psi on older Johnsons and Evinrudes, 130 is typical on many Yamahas. Ran a cold compression test and came back 100 psi on cylinder 1 and 92 psi on cylinder 2. Apr 20, 2015 · OK to own and operate a motor with low compression values whereas it is might not be OK to buy a motor that has better (but not perfect) compression values. Oct 2, 2013 · -- Short of having that kill switch, is there an outboard-equivalent to a coil wire that I can remove and ground?-- In doing some research on outboard compression, am I correct that "typical" numbers (#'s) are in the low-100's for larger HP OB's? The reason I ask is that the typical numbers for stern drives are in the mid-to-upper 100's. Customer: Hi checking compression what should it be?Mercury 2 stroke 2003 225 HP Selling motor, To obtain best reading should I check after warmed up or cold With throttle wide open our at idle position. Suzuki 9. Compare Yamaha outboard engines and find the ideal one for your boating needs. com Jan 4, 2007 · What should the compression be on a small 2 stroke outboard? 135 psi but pref 140. Generally, two-stroke outboard motors should have a 100 up to 120 PSI compression per cylinder. Jan 25, 2014 · Expected reading is found in the OEM service manual for your outboard. During a cold engine compression test, the cylinders both hit exactly the same at 100lbs. The specifications of outboards shown on this website may be changed or production discontinued without notice. Thank you, Joe Apr 2, 2018 · Hello, new to this forum and to Yamaha outboards. Yamaha outboards quick reference parts guideYamaha outboard weight chart (+power/weight ratio) Compression outboard boatsOutboard torque hp weight reviewmotors. Dec 15, 2011 · The first compression, how long it takes for each cylinder to get to full compression and the difference between all of them. Compression Nov 2, 2024 · Check Details 2 stroke mercury outboard compression chart. It may just be a lazy piston ring due to being left standing but you never know. Then I cleaned my carbs out, problem continues. 9's are 86 and 87 models respectively). com. Just totally clean, Im not used to seeing a used engine so clean. Find a detailed engine comparison to help you make the right decision. Jun 21, 2021 · Buy a Motion Pro compression test kit for your Yamaha outboard compression test at Partzilla. in a 4 stroke the myth went that if compression increased it was rings if not it was valves. purchased 2 years ago/boat has been sitting for years/motor very clean. May 1, 2016 · I have a 2005 merc 50 HP 2 cycle and mine are between 114 and 118 which I thought were low but I have a good friend in another state that is a mercury repairman and he told me this is fine. The older 115s and 135s had compression up in the 120s, 130s or higher but the later model engines designed to run on lead free low octane fuels went all the way down into the 90-100psi range. I am about to buy the respective engine used and i will have to make a compression test. 100psi would be very low for most normally aspirated motors. 9hp df9. I just decided to run a compression check and after pulling the plugs, it appeared they had water on them (cylinder 2 and 3). Showed 140 psi on all cylinders. Jul 28, 2016 · I have a new-to-me 2004 25 hp 2 stroke Mercury engine that seems to start and run well. 10% is acceptable on an older engine. Oct 31, 2006 · Bought a '98 Merc 20 for a couple hundred bucks but the pistons were frozen. The other question is what compression will be adequate and what variation between the 3 cylinders. . I know 140 isnt that low as I've seen motors with 7 Feb 24, 2014 · Same problem persists, stalling under load /no idle. Oct 30, 2021 · 2006 90 HP Yamaha 2-stroke, oil-injected outboard motor ran hot and now has low compression (30 psi) in the top cylinder. 9btxw5 outboard motors in stock and on sale now!Outboard measure Yamaha outboards quick reference parts guideYamaha outboards dimensions specs by myboatingshop. Much more than that, and it's time to diagnose further (like with a leak down test). I have a 91, 15 horse - over 1500 hours on it (don't use it as much as my pair of 9. The compression you should see will vary with the make and model of the motor. com/product/aftermarket/3ILR-MOTION- An outboard gas engine needs air, fuel, spark, compression, and unobstructed exhaust — in the right amounts and at the right time. I dont test compression much anymore on 4 strokes, a leakdown test is faster and more Apr 7, 2009 · Anyway, i would be gratefull if you aswer me the question about the exact compression in a brand new Yamaha 90hp, 2-stroke of 1992. Another good example of compression changing throughout the years would be in the OMC crossflow V-4 line. In addition, you should avoid having over 10 percent difference between your cylinders. As the piston travels up and down in the cylinder, the piston rings seal against the cylinder wall so the air/fuel mixture can be compressed at the top of the cylinder on the upstroke. My compression results were all in the 90psi range for all 6 cylinders. com: https://www. I know that the factory service manual doesn't mention numbers. Direct inquiries concerning Yamaha outboards to your country's distributor or local May 19, 2009 · Ask the experts on our Yamaha Outboard Forum for repair issues, diagnosing problems, links to diagrams, suggestions on buying parts and more. Boat totally loaded is about 2700 lbs with 4 people on it included and pushes 32 mph. I do see using compression values as a tool to beat the seller up with in order to try and get a better price. Put in water twice last summer/not much time for boating yet/first run-found plugged discharge/took home and cleared/second time-took for a good run/motor idles poorly/sluggish at low rpms/once up and planing ran smooth/45mph and 450rpm and up/ back at the dock/stalled out. May 25, 2011 · Re: Compression for a 115HP Yamaha 98-2005? Hello Just got back and the engine is a 1997 Yamaha 115HP 2 Stroke non-oil injected that is super clean, when the guy popped the cover off I was shocked. I'm looking at a bay boat with a 2001 Yamaha 150hp 2 stroke. its an old school thing that should have died off with the dinosaurs but the myth persists. Compression in cylinder 1= 100 2=60-70 (bouncing around/not holding pressure) 3= 110. I cannot tell you how many 4 strokes have passed a compression test with leaking heads,leaking valves and stuck rings due to carbon. My question is: What should the compression number be? This engine is very clean with very minimal use. Mar 21, 2009 · I was given a 1987 2 stroke 115 hp yamaha motor and I figured Id check the compression and check the spark. If the variation is more than 15psi between the two then you need to investigate. The compression is less important than the variation between the cylinders. thinking it might have had problems since it was free!! anyway the compression was 140 in all 4 cylindersit is a 2 stroke V4. May 26, 2009 · Right on the money, Cajun. Always read your owner's manual before using the outboard and be sure to use it properly. Jul 5, 2008 · "Tom, the cough or sneeze is m "Tom, the cough or sneeze is most likely only a minor adjustment on the carb. See full list on bornagainboating. I have been told that Mercury doesn't publish compression numbers. We tested our Yamaha T60 outboard with a Motion Pro compression test set, which is available on our sister site Partzilla. 1997 states in section 1C-6 "Important Information", Compression Check: REMOVE SPARK PLUGS Install gauge Hold throttle plate (carb butterflies) at WOT (fully open) Crank engine till gauge peaks Record the reading Check all NOTE: The steps for compression testing a 2003 Yamaha T60 outboard are the same or similar for all outboard engines. Question is, are these compression readings Jun 5, 2024 · Check Details 2 stroke mercury outboard compression chart. But this is just a rough estimate since you should still try to check using a compression test. covkegb ivnlf jpq mdp kijo kdbw hnwej qpey ihmu elvcz