Carb issue

[Casper60]

Running a 4777 on a 602. Fired it up for the first time this year tonight and it started dumping fuel from the vent tube on the secondaries. If I run it with fuel just going to the primaries, it runs fine. Any ideas? Carb had 3 races on it last season and worked flawlessly. Sat in a case all winter until it was put back on. Nothing else has been replaced or changed from last season.

[rubbinsracin]

So its just dumping a ton of fuel in the secondaries?

[Casper60]

Yes, it pours out the tube into the secondaries, floods the engine and stalls

[rubbinsracin]

Sounds like its missing the jets.....might be worth double checking no one took them out.

[Casper60]

No, I already pulled it apart. Jets are there, float is not jammed, nothing in the metering block is plugged up. Just seems odd that it worked flawlessly when I took it off the car and it hasn't been touched since and it's doing this.

[rubbinsracin]

Gasket that's bad? Maybe put a rebuild kit on it and see if its still happening. Do you have your back float set right?

[cheaterleaddog]

tube that sticks straight up above carb?

Some times the fuel gets sucked out of vent tube and you can't see it. I bet the needle and seat has a piece of dirt in it or dried old fuel. if you remove bowl and then attach a clean rubber hose to the inlet and blow through it you should be able to stop flow of air by raising float with your finger if air keeps coming out clean needle and seat or replace.

[Casper60]

Yep, that tube.

I had an e-mail from the carb builder late last night that stated pretty much the same thing you did. I'll spend some time at the shop tonight going through it and see if this sorts it out.

Thanks guys!

[7uptruckracer]

Like they said stuck needle and seat the rubber deteriorates and it sticks especially it the bowl was dry all offseason happens all the time!

[zlssefi]

same

I had a 4777 do the same thing. Had a piece of teflon tape stuck under the needle on the seat.

[Casper60]

We got it figured out. I didn't see anything visibly wrong with the needle and seat, so I'm going to assume there may have been some debris in there. Blew everything out, put a new needle and seat in since I already had one and now it's back to normal.

I appreciate the feeback guys!