Evinrude 60hp 1990 Failed Again and Again

[RonA]

Purchased boat and motor 1996, low hours, motor failed within 2 weeks, burnt hole in #2 piston. Repaired however failed again (hole in top of #2 piston) within 40hrs, general running around 4000rpm. Fitted evinrude supplied motor top end with old running gear, tuned to run rich and prop was resized. Has run well for around 60hrs and then started to cut out, would restart immediately but then cut out 5 mins. later. Have done another compression check #1 110psi, #2 95psi, #3 105psi. All repairs have been done by the Evinrude dealer who now says it looks like #2 has failed again - enough is enough. <br />Has anyone had similar problems (what is cause) and why should motor cutout due to a piston problem?

 

[steamboatwilly]

Re: Evinrude 60hp 1990 Failed Again and Again

It might be running lean on the cylinder that gives problems.Thats a good example of why plugs and pistons should be checked for uniform color once or twice per year.Might be a high speed jet is stopped.I would make certain the carbs.are perfectly clean.

 

[JB]

Re: Evinrude 60hp 1990 Failed Again and Again

Sounds like symptoms have been repaired without repairing the cause, RonA.<br /><br />I suggest that #2 is running too lean and that the carburetor is at fault.<br /><br />Your compression is currently within spec.<br /><br />Engines don't cut out because of a piston problem. They cut out because of a fuel or ignition problem. Those, if left uncorrected, cause the piston problem.<br /><br />Good luck.

 

[Joe Reeves]

Re: Evinrude 60hp 1990 Failed Again and Again

Also..... If any metal was embedded in the cylinder head, and the head was reused instead of being replaced, that could very well result in preignition. That would lead to the piston damage you describe.

 

[OBJ]

Re: Evinrude 60hp 1990 Failed Again and Again

You may also quiry the dealer who performed the first rebuild and ask if a carb overhaul was part of the rebuild.....which it should have.<br /><br />Wanna bet he says yes?

 

[clanton]

Re: Evinrude 60hp 1990 Failed Again and Again

You have to do the service bulletins, which include a jet kit for the carbs and reduced timing. Prop to 6000 rpms WOT. There are 5/6 bulletins, try search. After market pistons may need more clearence.

 

[Dhadley]

Re: Evinrude 60hp 1990 Failed Again and Again

Ditto. Plus you have to realize that at 4000 rpm youre not really into the high speed jets. But you are running at full advance timing. <br /><br />Do all the things listed above and then look at the intermediate jets. We've seen this same scenario many times. You need to make sure youre running on cool plugs like the Champion QL77JC4's. And no other brand. Then richen up the mid range jets slightly. 6000 rpm is a must for top rpm.<br /><br />The most troubling part is that your mechanic is just changing parts. Hes not finding the cause of the problem. A damaged piston is a result -- not the cause.

 

[TimMattson]

Re: Evinrude 60hp 1990 Failed Again and Again

My OMC guru showed me how to use a 12volt timing light hooked to any spark plug wire+12 volt power to watch for high speed jet operation thru the carb with the baffle off.All 3 should spray the same.It works slick,but your problem may be ignition,carb ,fuel,or?<br /> My failure was right after the wintertime fuel hit the pump and using Premium added to the problem.The 10% alc. will raise the temp. a bit.<br /> Put a Racor in the fuel system if it AT ALL looks dirty when pumped into a glass jar.<br /> TM