Re: 1980 150 HP Mercury V6 - not getting full power
Hi!
I?m having almost the same issues with my 1989 4-cyl 115 elpto.
As a matter of fact I was testdriving my boat, making some turns and crossing some wawes and it suddenly went down to about 3000 rpm. Sounds familiar?
I have changed the "big" fuel filter (there are one more small on the enrichment circuit on my engine wich I haven?t found yet) and rebuilt the fuel pump.
The fuel pump weren?t broken what I could see, but the diaphragm were a bit stiff. Going out on a test ride and no difference.
Just as you I could get my engine momentarilly have some power while pumping on the hose pump. That leads me to the absolut opinion that it has to be something with the fuel delivery. As you said you can?t get the same effect after the pump rebuild might just be the fresh pump are not so easily to bypass as before.
So what to look for?
-Obstructions in a fuel hose? Not likely, would be such a big thing to get stuck there.
Something clogged in some of the carbs sounds more possible. But what? and how to find out wich carb. I don?t dare to take off ingnition wire one by one in scare to damage the cdi/coils.
I would suggest:
-the float needle valve in some of the carbs is stuck in closed position or some jet are clogged with dirt.
-or an intake gasket is leaking between carb and engine, or carb is loose. (and sucking air/get lean)
A way to check this is to spray starter gas around the intake manifold (just prevent from getting in to the air intake) and see if the rev is changing.
So the conclusion is we having the same problem, and should definitly keep each other posted how we solve this. You might have had one carb that had a little flooding issue wich you adressed but maybe the real problem is one or two others that goes very lean.
Help appreciated how to find wich carb to look for, then when the problem is found I would like to tear down all carbs, but not in this first step.
Cheers!
