max rpm 2700, 1970 60 hp evinrude

[ice_667]

I've done just about all I can think of to this motor. Compression is good, fuel pressure good, points set, new coil pack, the rest of the electronics are fairly new, and the carbs are clean and linkages set. Still, I can't get more than 2700 RPM at WOT. It runs great, just peaks out way too soon. Can't seem to get more than 3000 RPM in neutral. Don't know what else to do. Somebody please help or I'm going to go buy a new motor. Thanks

 

[JB]

Re: max rpm 2700, 1970 60 hp evinrude

Yo, Ice. I suspect that one of the things you trust to be true isn't. That 3 cyl. OMC is one of the best outboard engines ever. Your symptoms say it isn't getting enough fuel or enough ignition advance or the carb throttles aren't opening all the way or one cylinder is dropping out or not making power. See what happens if you disable one cylinder at a time

 

[ice_667]

Re: max rpm 2700, 1970 60 hp evinrude

J.B<br />Could adjusting the timing get me 2000 more RPM. I've changed it a bit before, but but wasn't sure how much I should push it. I'm going to check things out again tonight though. Thanks for your help.<br /><br />Keith

 

[Dunk]

Re: max rpm 2700, 1970 60 hp evinrude

You shouldn't have screwed with the timing. The way you time that engine is when it's running at 4500rpms pushing the boat with a timing light. The timing is critcal, to much advance and you'll melt pistons in a heartbeat. I hope you counted how many turns you took on the timing so you can put it back where it was..This is something that doesn't change on OB's. Usually theres a sticker on the carb horn stating what the timing advance should be. OMC's V4's and later the V6's where all timed a few degrees less for breakin. Then at the 20hr check the dealer set the timing up to specs. I'm not sure if they did that with the 3 cylinder engines. Take my word, there only two things that will screw that engine up good. One is timing and the other is over propping it. They have to be proped to turn 5500-6000 at WOT or combustion temps go right off the scale.<br /><br /> My guess is you are only running on 2 cylinders. If you are still using the polar gap type spark plugs(surface gap) get rid of them and put a set of L77-JC4's in her. I had a 69 55hp that loved to run on 2 cylinders till we changed the plugs to the regular type. If the plug don't help I'd be checking the coils.