Not getting enough RPM!!! WHY????

[PHOTOG]

...this boat... Okay, power isues still looming, 1980 mercury 80hp outboard, carbs rebuilt, fuel pump rebuilt, new fuel tank-line-bulb, new fuel line connectors.



engine only gets to 4200 rpm...19 pitch prop...



played with the trim and didnt gain anything.



where might these rpm's be hiding? And I checked and the butterflies are all the way open at WOT...this is beyond me.

 

[DRIFTER_016]

Re: Not getting enough RPM!!! WHY????

Need more info.
Is this a new setup for you?
If no, did it rev up before with that prop?
If it did, have you checked all cylinders plugs for fouling/spark?
Have you checked compression?
Have you checked timing?
If you are only hitting 4200 one cylinder may be weak/not firing.