Holley Carb Problem

[Warren]

Just when you think it can't get any better, sunny day, etc. Car running luverly, pulled up at lights and it stalled.

Been starting all afternoon on the button no problem but now it won't have it.

First place I checked was the carb, filter off, see image, the rear two barrels are dripping with fuel. So I held the fuel line closed until it stopped. Let go and they drip again causing flooding. I got the car re-started by holding the line closed with some pliers and cranking until the fuel cleared and the car caught.

Drove straight home keeping the revs up and into the garage, of course as soon as the car idled for a few minutes it once again overfueled, and cut out. Same problem, engine not running fuel dripping furiously down the rear barrels. Tried adjusting the float levels but now stumped, can anyone help? Is it going to be a stuck needled valve or will something else be causing this. If stuck valve most likely how easy are these to strip?

Cheers
Warren

[john cohen]

Hi Warren That does sound like needale valve m8 . It happened to me when i was at my SVA but it cleared its self . As for how easy to do i cant help but someone will be along soon to tell you .



John

[Warren]

Hi John

I would agree but I am sat hitting refresh hoping the experts turn up and tell me how to fix it. I also have a suspicion that the accelorator pump may have something to do with it but again I would like those in the know to outline any expected strip down problems etc.

Also I don't want to start stripping if the advice is " replace this & that whilst you're at it" or "you will need xyz gaskets"

Cheers
Warren

[conrod]

Warren,

It's quite a straightforward job. All you need to do is to remove the float bowl. It's held on by four bolts, and you'll also need to undo the fuel pipe union. Make sure you wrap loads of cloth under and around the bowl before you start, as fuel will pi$$ out when you undo this lot! To avoid the risk of fire, 1) only do this when the engine, and particularly the exhaust headers are cold and 2) have a fire extinguisher handy.

Unless you've covered a high mileage, the likelihood is that the cause of the needle valve sticking is dirt, rather than a worn valve. Just squirt carb cleaner over and through it. If there is dirt in there, and you don't have an in-line fuel filter fitted, it would be a good idea to fit one in fuel line just before the carb (make sure it's a plastic or metal one - glass ones are too dangerous.

The only spare you might need is a new gasket. There are actually two gaskets - one between the carb body and the metering plate, and another between the metering plate and he float bowl. If you take care when removing the latter, you should be able to remove it without tearing the gasket. BTW, if the float bowl won't budge, try tapping it gently with a wooden or rubber mallet. If you do need to prise it be careful not to damage the lip, otherwise you may end up with a fuel leak there.

So it might be worth getting a spare float bowl gasket before you start, just in case. If yours is a 4150 or 4160 then I have a spare. You can then bolt it all back together. Don't overtighten the four bolts, as it's esay to strip the threads if you're too heavy handed. The fuel union nut is another matter though - I really have to tighten mine down hard to stop it leaking. That's the main reason for having an extinguisher handy! When you start the engine (if you have a mechanical fuel pump it will require a lot of cranking to pump the fuel into the float bowl) check immediately for leaks. If so, stop the engine and rectify.

Hope this helps.

[conrod]

Warren,

Re the accelerator pump. This is a small pump on the side of the carb that's actuated when the throttle spindle turns and injects fuel directly from the float bowl into the venturi. It won't be related to the carb flooding - that's definitely a sticking float needle valve.

[Warren]

Thanks Alan, will have a go at this tomorrow evening and see what happens. I'll go steady with the bowl and try get the thing out without damage to the gasket.

Rather than pay you/rob you of your spare I assume these are off the shelf items from Real Steel/Repower et al? You know what it's like, you let someone have something you haven't used for a decade and the next day you need it....

Cheers
Warren


P.S. Sorry mate, one more thing, the tube that goes from one float bowl to the other look to be about 6/7mm and starts just behind the fuel inlet, rigid and goes straight across. Is that simply sealed by 'o' rings so you just undo the 4 bolts and pull, the tube will slide out??

Cheers again
Warren

[conrod]

Originally Posted by Warren

Thanks Alan, will have a go at this tomorrow evening and see what happens. I'll go steady with the bowl and try get the thing out without damage to the gasket.

Rather than pay you/rob you of your spare I assume these are off the shelf items from Real Steel/Repower et al? You know what it's like, you let someone have something you haven't used for a decade and the next day you need it....

Cheers
Warren

You should be able to get them from there. Or alternatively from Mark (Dusty's Speed Shop) on eBay. He's only got the metering plate gaskets listed at present, but he probably has some.

If you get stuck I have quite a few spares, as I ordered a job lot! Drop me a PM if you need one.

[Warren]

P.S. Sorry mate, one more thing, the tube that goes from one float bowl to the other look to be about 6/7mm and starts just behind the fuel inlet, rigid and goes straight across. Is that simply sealed by 'o' rings so you just undo the 4 bolts and pull, the tube will slide out??

Cheers again
Warren

Wasn't quick enough with the edit

[Warren]

Hope this attaches OK

Warren

[conrod]

Replied via PM, but to confirm - yep it's a fuel pipe. As I said, different from mine - yours appears to be sandwiched between the two fuel/float bowls so probably has an "O"-ring at each end as a seal.

Good luck, and if you need furher help by all means give me a call.