982 Manifold Repair?

Tue Jul 29, 2014 9:29 pm

On a 982-20hp Onan what is the best fix on a leaky manifold, without replacing it?
A new manifold is too expensive for me.

Re: 982 Manifold Repair?

Fri Aug 01, 2014 7:22 am

Red,
Where or how is it leaking? I've seen double gaskets or thicker gasket used for the carb.

Re: 982 Manifold Repair?

Fri Aug 01, 2014 8:02 am

Bill I have to get it apart. It cuts out when you hit it. You have to nurse it along to speed up or else it will sputter and pop if you are not easy on the throttle. I know I can't even plow with it because I know it would cough out under power.
I fixed it once with some kind of liquid gasket and all new bolts evenly torqued but it did not work.

Re: 982 Manifold Repair?

Fri Aug 15, 2014 7:47 am

I kind of doubt that the manifold is leaking. I'd bet the carb needs rebuilt. It's just not real likely that the mainfold is the problem.

Re: 982 Manifold Repair?

Fri Aug 15, 2014 9:31 am

Bill thanks. Could it be the spark as well.

Re: 982 Manifold Repair?

Fri Aug 15, 2014 10:56 am

It could be the coils getting weak, but typically when this happens you loose top end power after the coil gets too hot. Then once it cools down, the tractor will start and run fine until the coil gets too hot again. Not saying it couldnt be a spark issue. Yours really sounds like a fuel/mixture problem, either not getting enough fuel or not having the fuel mixture correct for higher RPM operation.

Having said all of this, there is always the issue that the carburetor could be warped and not sealing to the manifold. This is pretty common on the Kohler engines, so I'm not sure exactly of the setup on the Onan engine, but it just came to mind. However, I think when the carbs are not sealed to the manifold you can barely get the engines to run at all because the loss of vacuum doesn't allow fuel to be drawn into the engine. Again, on the Onan engine, with the carb on top of the engine rather than on the side like a Kohler engine, I'm not sure how it would act under this situation.

Re: 982 Manifold Repair?

Fri Aug 15, 2014 1:52 pm

Thanks Bill I have some checking and head scratching to do.

Re: 982 Manifold Repair?

Fri Aug 15, 2014 3:24 pm

Try a container of fuel line, carburetor cleaner in the gas tank.

Re: 982 Manifold Repair?

Tue Aug 19, 2014 9:22 pm

Seafoam run it and let it sit and soak.

Re: 982 Manifold Repair?

Fri Oct 31, 2014 7:30 pm

Bill you were right. The manifold was fine.
Always Check the Obvious and Don't be in a Hurry.
I set the Carb, (H and L speed idle and it now works fine). I ploughed with it 2 days ago.
She had lots of power and no lose of power.