RPM on 150hp

[r j f]

I have a 1985 evinrude 150hp on a 20ft wa with a 14 1/2x 19 prop. The boat weight is about 3200lbs with motor. This has just had a ring job and carb rebuilt this year when I bought it. However I'm topping out at 4200 rpm. Any ideas how to get this up to around 5500 rpm. Other than this the motor runs great. Thanks for any info.

 

[voodoo]

Re: RPM on 150hp

Do a compression and plug check to ensure you are making all the 150hp, then go to a 17 inch prop,you should see about a 10-15% increase in rpm's (depending if you get to the power band), you may need to go to an even lower pitch.

 

[r j f]

Re: RPM on 150hp

voodoo, compression checked out very good. I was running double oil during the breakin on the rings, could the be messed up though the motor sounds good.

 

[Dhadley]

Re: RPM on 150hp

The prop may be a bit steep as suggested but we're 1600 rpm off. Lets start with the basics. Thats the only way to build this map. We gotta know where we are now so we can tell how to get where we want to be.<br /><br />A service manual is a must. A generic is betetr than none by far. An OE specific is better yet.<br /><br />I know you said the compression is good but you didnt say what it was. Check it and post the results.<br /><br />Make sure we've got spark on all 6 all the time.<br /><br />Double check the timing. Whoever rebuilt it may not have that right.<br /><br />Did they clean the carbs?<br /><br />Check the sync-n-link. Perhaps one of the linkages (throttle or spark) is not going all the way.<br /><br />If possible have a shop run it on a test wheel. If it comes up to spec, we know to look at the boat.<br /><br />Good luck!!

 

[voodoo]

Re: RPM on 150hp

Me bad.. I assumed a GOOD plug check would tell us if all 6 were doing the same thing..you know suck, squish, bang, blow. The carb rebuild is a good indicator that the timing and sync needs to be looked at.

 

[r j f]

Re: RPM on 150hp

Dhadley--compression all cyl. 95-98--carbs were just rebuilt--timing ok---what is the best way to check sync-n-link?<br />Thanks for all the help