85 Force 85-Runs great then not so great

[rob noble]

I have put new gas line(including inside tank), squeeze bulbs, taken off carbs and checked(they were clean as a whisle), installed new plugs, replaced fuel pump diaphram and gasket. Ran great first thing out this morning, parked for ten minutes, start back up and runs max about 25 MPH, was running 40 before the I took the 10 minute break. It will occassionally take off and run great breifly, then go back to half blast.
I hate to start buying power packs at $300+ each just to find out that isn't it either. I thought I hade a fuel problem because the line inside may tank had deteriorated faily badly. This thing had sat for 8 years in total neglect.

 

[imported_LakeRunner]

Re: 85 Force 85-Runs great then not so great

and did you decarb it? Check the plugs and see if they have fouled and you may also want to check the reed gaps.

 

[eurolarva]

Re: 85 Force 85-Runs great then not so great

What color is the stator on your motor? Red or Black? If you have a manual I would test that first.

 

[Matthew A.]

Re: 85 Force 85-Runs great then not so great

You mention replacing the fuel lines. Have you checked to see if there is water that may have accumulated in the fuel tank/s. An easy way to check to see if your motor's running the way it is due to water in the fuel is too hook up a portable above deck fuel tank. One that you know is clean inside. Fill it with good clean fuel/oil mix and run your motor using it instead of your normal fuel tank. Also, you may want to try checking the particulate screen at the fuel pump for debris that maybe blocking fuel. Another thing to check is to make sure the fuel tank is vented correctly. If your tank is an above deck type be sure the small thumb screw which is the fuel tank vent located on the fuel cap is not tightened down. If your tank is below deck check the tanks vent hose for kinkage and the vent opening to make certain it isn't obstructed in any way. Last, there could also be a blocked air vent passage on one of the carbs. A blockage in the air passage that vents the float bowl could be preventing fuel from entering the float bowl. Unlikely, but it doesn't hurt to check.

 

[rob noble]

Re: 85 Force 85-Runs great then not so great

I have a portable tank with new lines and gas, had cleaned tank thoroughly when replaced deteriorating gas line inside the tank. This is a steel tank, also have 2 plastic ones that give the same performance. All carb lines are clear, inclding atmospheric vent hole to float, I poured out the gas thru them when I took them off the motor. The stator looks OK just looking at it from underneath the flywheel, I had checked all the connections to coils and mags, and grounds.
The wife finally gave me the ultimatum and I took it to the shop Friday AM. Will post what was wrong when I get it back-Thanks fellas, Rob