85hp lack of power under load

[pmosier]

1975 Evinrude 85 hp. I have been around the boat for years and it has been a reliable boat. A carb leak forced rebuilds for both carbs. Now the boat runs perfect when out of the water, it idles and raps right up when you give it throttle. When in the water, it only goes about 10 mph, but one time it just took off and ran like it should for a bit, and now it's back to it's sorry state. I have 125 psi compression on all cylinders. I was told there were recent spark plugs, but (when looking from the back of the boat forward) the right 2 plugs had some buildup on them and the rt 2 were perfectly clean. The butterflys open all the way at WOT, ummm, that's about as much as I know so far, any ideas?

 

[ezeke]

Re: 85hp lack of power under load

Be sure to use Champion QL77JC4 plugs at .030 gap.

Sounds like something is not quite right on your carburetors. Did you put new floats and needles in? Did you clip the float arm to the needles?

http://www.boatsetup.com/Spark Plug Chart 2007 BRP.pdf

 

[pmosier]

Re: 85hp lack of power under load

my friend who owned the boat before me rebuilt them and he is a pretty solid mechanic, he bought and installed complete rebuild kits. I'm guessing maybe some garbage got sucked out of the tank. I'm going to pull the tank and clean it, pull the carbs, and have a look at the float bowls. I'll have those exact plugs as well. I am sort of wondering if it could be an isolated issue like a failing spark plug wire/coil.

 

[richsbca]

Re: 85hp lack of power under load

Think there may be some fuel line issues, or fuel filter issues. I messed with all that stuff and it ran fine before I messed with it; well, and before I forgot to pull the plug and it completely filled up with water then trying to start it like that. Those fuel lines were pretty hardened and I did abuse them a bit!LOL! Won't be long before I come up there and run circles around you in my Lund!!!