1996 force 9.9hp fuel recirculation system

[robert53a]

Hi I acquired a 1996 force 9.hp short shaft motor that has good compression fine spark and clean carburetor. but won't run good. It is hard to start and won't idle well and the carb is hard to adjust. I have been through every thing including the fuel pump.(good diaphragm). while I had the fuel pump off I pulled the cylinder drain cover off to find that there was a good half cup of oil that came out of the bottom of the block the cover block screen were completely crudded up. I used carb cleaner to clean it and blew it out with compressed air. What is the function of this block? is it a drain or for pressure equalization?, just curious and I'm trying to get it running right. I have used the manual on everything, but is really doesn't explain how the thing works. Thank and sorry for the long post.....Robert

 

[pnwboat]

It helps to prevent fuel/oil mixture from puddling up at idle and low RPM's in that part of the By-Pass passage and causing a rich mixture. Any puddled fuel/oil is sucked out and routed directly into the By-Pass ports in the side of the cylinder and into the combustion chamber. Higher RPM's creates enough flow or velocity through the By-Pass passage so the fuel mixture doesn't have a tendency to puddle.

The drain cover has a one way valve or a very small metered hole to suck the puddled fuel. A half a cup of fuel/oil seems like quite a bit to be sitting in there. I wouldn't be surprised that you're having poor low speed problems.

 

[robert53a]

Thanks for the information, much appreciated. I will report back when all is re-assembled. I'm hoping for a good outcome.......Robert