engine problems 1997 force 50 hp

[larry456]

When I full throttle the engine it will run full speed for about 5 minutes and goes to half speed like running on 1 cylinder. I have changed the impellor put a new carb kit and new fuel pump kit plus a new prop and removed the old gas and replaced with new gas. I also replaced the spark plugs. I need some good advice about my problem.

 

[Unbalanced]

Re: engine problems 1997 force 50 hp

Do a compression check.

What happens after it seems like it's running on one cylinder? Does it continue to run that way? What do the plugs look like? Do they look the same or is one "cleaner" than the other? Does the primer bulb go flat? Does pumping the primer bulb while it's running different change the way it runs?
Have you tried running it without the cover on?

There are a few things that come to my mind. A leaking head gasket. A fuel delivery problem. A coil that is going south - agrivated by heat. Or the engine is being choked out by exhaust gasses.

 

[larry456]

Re: engine problems 1997 force 50 hp

I replaced the stator on friday and I still have the same problem. It goes to half power at the same running time and place, I can let it idle for a few minutes and it will start to run on both plugs, but only runs for about a minute and shuts down to half power. As I stated before I have changed the plugs, rebuilt the carb and fuel pump, checked the coils and drained the gas tank because the motor has been out of use for a year and all is good. I plan to order a switch box today and change it out. If you have any advice please reply.

 

[Unbalanced]

Re: engine problems 1997 force 50 hp

Hi Larry.

Why did you replace the Stator? Did it test bad? I hope you're not just throwing parts at it in hope of stumbling upon a solution.

It seems to me that you have a fuel delivery problem. If the motor will start and run properly for a minute, then run on 1/2 power consistantly, then I would say that one carb bowl is filling too slowly. Either the float is not set properly or there is a restriction in the fuel line. You might be sucking air somewhere as well.

Take the carbs back off and check the fuel lines.