BikerBill

Fuel Leaking from Nikki Carburetor Bowl

Some background: Generac 4000 EXL portable generator with Generac engine and Nikki carburetor. I always drain all the fuel from the gas tank and remove the carb bowl, dump the fuel from it and reinstall. Recently I needed to use the generator so I added fuel and fired it up. It started and ran without a hitch. But when I brought the generator back into the garage I noticed it was leaking fuel.

I traced the leak to the top of the fuel bowl, by the O-ring seal. I know fuel is not supposed to be up that high so I took the carb bowl off. The float is plastic and does not have any fuel in it. With the bowl off I blew into the fuel inlet while I raised and lowered the float. I could blow easily when the float was low and couldn't blow when I raised the float. Neverthless, I took the float and float valve apart. No crud, the float valve moves easily.

I'm wondering if the rubber-tipped float valve has dried out and doesn't completely seal anymore. Fuel doesn't gush out around the bowl, it's a fairly slow leak. The unit has stood empty of fuel for the last three years. Can I soak the rubber-tipped valve in something to soften/restore it? I hate to buy a rebuilt kit just for the float valve. Or is there something else I should pursue?

Thanks.

cheese

I imagine that you can either clean the needle and seat, or clean the seat and replace the needle to fix this problem.

BikerBill

Any suggestions for cleaning the rubber-tipped float valve? I believe I have some automotive aerosol throttle body cleaner that is supposed to be safe for rubber. The seat is brass and looks fine but I'll take a closer look with a brighter light and magnifying glass. Is it not wise to leave the fuel bowl empty for long periods of time (years)?

cheese

Yes, it's best to leave it dry if you will be letting it sit for more than a few months. If you hadn't, you might be looking for a new carb now rather than just fixing a leak. Use regular carburetor cleaner in the spray can and a q-tip to clean the needle tip and down in the seat area. I like next-dimension brand carb cleaner from advance auto parts best.