582 engine flooding during start

[RockDoc54]

We have completed our renovation of the Kitfox IV we picked up a few months ago (last condition inspection was in 2013) . Engine ran fine during our pre-buy inspection in April. Has had no fuel in the system since then. Has a 582 blue head engine. When we attempted the engine start, got a lot of excess fuel coming out of the air cleaner. Engine only runs (for a minute or so) when fuel pump and fuel valve are turned off. When turned on, engine floods and dies almost immediately and raw fuel appears to run out of the overflow orifice (center port in the intake of the carb) . Has had only 100LL, no mogas with alcohol. I pulled the bowl off one of the carbs. No debris, floats are good, float needle looks OK, but seems to not be shutting off the gas when the bowl fills up. I'm thinking it may be the float needles(s) need to be replaced due to length of time since last had fuel in the system, even thought they look OK. Any suggestions or comments on the subject would be appreciated. Thanks!

[Grayson.rotschy]

If you've checked the carb floats allready try checking the primer plunger if you have one. If the oring in the plunger goes bad fuel can free flow through the primer and flood the engine.

[buckchop]

Have u tested the needles to c if they leak? Put a piece of hose on the carb inlet, suck or blow in the hose close and open the needle and float by hand? Only need about 3psi to check it.

Also u should check the psi that ur fuel pump is puttin out, u may need a pressure regulator in the system, just cause the pump says puts out a regulated psi, i have found some to b way over the regulated pressure b4.

[buckchop]

Also if u have a primer pump make sure its not bypassin fuel when ur fuel pump is on when motor is running those go bad least once a yr for all of us. U can just pinch off the little lines with two clothes pin to test it.

[Navycposd]

Is the overflow of fuel from one carb or both? In your rebuild, did you change or add an electric fuel pump? Once the system is primed, turn off the electric pump and try starting on just the pulse pump (we ran these engines for years on just the pulse pump). Yes, the floats and float valve are supposed to shut off flow, but if you have too much fuel pressure it may be pressurizing the bowl, and pumping up into the carb intake through the main jet.

When you reassembled the carbs did you put the main jet needle in the correct order with the Spring Cup? If the main needle is too high, because the needle snap ring is on the wrong side of the Spring Cup, it can allow fuel to be pulled into the intake even though the throttle is at idle and the slide is all the way down. Since it is unlikely for both float valves to be stuck and if the float valve seats were an issue it excess fuel would flow out the overflow tubes, not push into the intake, recheck your main jet needles for proper stack-up (really simple to put together in the wrong order).

[sioux201]

I just ran through a flooding problem on Bing being 54s, vent tubes to the carburetor Bowls were clogged!!!