my boat use to get about 6500 RPMs at WOT, now it is getting 4000 and not getting on plane. rebuilt carb and fuel pump but no help. starts and idles great. i put it in gear and the RPMs are at about 700 as it should be, excelerates fine, just won't get up there. any help i would appreciate
How's the compression? When was the last tune up - pleugs etc? Any prop damage? Are you sure both cylinders are working?
__________________ "When you see yourself doing something badly and nobody’s bothering to tell you anymore, that’s a very bad place to be. Your critics are your ones telling you they still love you and care." Randy Pausch 1960-2008 The Last Lecture
I am getting 99psi compression on the top, 100psi on the bottom. I am getting spark to both plugs. there is a little prop damage, just some minor nicks. I'm not sure what ya mean by a "tune up". plugs have been replaced and gapped properly (.30).
when you rebuilt the carb, did you disassemble completely, soak all metal parts in solution, blow out a llt he orifices with compressed air, run a small wire thru all orifices, and reassenble with a new rebuild kit. it you didn't you wasted your time. are you sure your llincage is correct after the carb rebuild. may need a linc n sinc, follow steps in manual.
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Well if you have spark, good plugs and your compression sounds good, it might be the fuel system. I would concentrate on the carb.
Make sure your linkage is opening all the way. Have there been any changes to the boat? Is the bottom clean? There are alot of variables and one by one they have to be eliminated.
__________________ "When you see yourself doing something badly and nobody’s bothering to tell you anymore, that’s a very bad place to be. Your critics are your ones telling you they still love you and care." Randy Pausch 1960-2008 The Last Lecture
Copy the following link without the quotation marks into your browser and then try this site for a comprehensive, free manual for your motor. Just scroll down to the 15hp entries. The first one is about 60 pages so be patient if your connection is slow.
I have the manual on my motor. Everything checks out fuel wise and it has its original prop ( I am only owner). I did use solution, and compessed air to clean carb. replace all parts, including top, roller and screw. The psi of fuel getting to carb if right according to manual. It was suggested to me to squirt gas mix into carb at WOT. if it reved it was a carb prop. but if it bogged, then it was getting enough gas and i need to check my coils, could be losing spark at high rpm?
when you did the carbs did you check the link and sinc between the elect and carb. this being out would keep the rpms down . the timing and the carbs being out of sinc. this advances the timing and the carbs at the proper rate ,
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'90 15hp evinrude has low RPM's at WOT
Linear Mode
