'67 Holley Problem

[Michael M.]

Thanks in advance.

[Clem Z.]

Re: '67 Holley Problem

if this carb has side pivot floats make sure the pin that holds the float has not come loose in the bowl and allowed the float to move and hit on the metering body. tap the pin to make sure it is all the way into the float bowl

[Gerard F.]

Re: '67 Holley Problem

Mike,

This might not be the answer to your problem, but here are a few things to check:

1. Look for any slop fore and aft in the pivot of the float within the fuel bowl and the alignment of the float with the the pivot. It is possible in driving, that the float, with slop or misalignment, will move forward or aft, and hang up on the inside of the bowl or metering body or plate. This could be a particular issue on the secondary side where there is less clearance between the float and the metering plate. I solved a percolation problem one time by just bending the float back towards the back of the bowl.

2. Make sure that all the little vents in the air horn on top are free and clear to the metering body or plate. A blocked vent could cause siphoning of gas into the air horn after shutdown. I have found two 3810's with undrilled or block vents from the factory.

3. On a 3810 there is no way to externally adjust the float level. Pull the bowls and check the bowls for the correct gage distance to the top of the bowl in an inverted position. The 67 Chassis Overhaul Manual is the only manual I've seen with the correct adjustment procedure for a 3810. The 67 Service Manual is too generic.

Then take two Advils and get a good nights sleep

[Michael M.]

Re: '67 Holley Problem

Thanks for the responses.

[Clem Z.]

Re: '67 Holley Problem

Thanks for the responses.

do you have the bronze fuel filter and gasket behind the fuel inlet fitting ??

[Gerard F.]

Re: '67 Holley Problem

Mike,

My wife gives me the same stuff, maybe yours is right this time

However, I was talking about the little vents inside the air horn. There are 4 on the primary side and 4 on the secondary. 2 of the 4 on each side are idle vents, the other 2 on each side are high speed vents. They all need to be clear. (Yes, a Holley 3810 does have a secondary side idle which is adjusted from the primary side mixture screw.)

The only other thing I can think of which could be a problem would be fuel pressure, if you have a replacement fuel pump. The 3810 was rated for a maximum fuel pressure of 6 psi. Over that you could be blowing through the floats seats.

You are probably on the right track. Try the new seats, then make a decision.

[Charles S.]

Re: '67 Holley Problem

You might also check the float drop level. This is the opposite of the float shutoff level. If this lets the float drop to far when the bowl is low or empty, the needle can come out of the seat to far and cock going back in preventing shutoff.

Frankly I doubt it is your problem but it is one of those things many people don't check and can cause problems, so when you have looked everywhere else, this is reasonable to check also.

[Timothy B.]

Re: '67 Holley Problem

Michael,

FWIW, One other thing to consider, if the fuel filter or sock in the gas tank is not doing it's job small particles can keep the needle from sealing in the seat. Probably not the problem, I think your on the right track changing needle and seat and re-adjusting the float level.

If you submerge the brass float in a pot of 200* water the air inside will pressurize and if there is any leak around solder joints etc. bubbles will rise from the leak point. This will ensure the float is OK.

Don't do it in wife's tea pot..

[Jeffrey B.]

Re: '67 Holley Problem

Mike,
I had this same problem with my 66 small block and went through many of the same things you have tried including the new needle and seat assembly. I finally installed a small canister style fuel filter between the steel fuel line and the fuel pump in the rubber hose that connects them. My flooding problem was resolved. I know this would not be a good idea if your car is judged, so I'm just offering up my experience with the flooding problem. Also; my carb is the original and has the brass filter installed.
Good Luck,
Jeff

[Jim T.]

Re: '67 Holley Problem

Thanks for the responses.

Michael I have bought brass floats, fuel bowl gaskets, metering block gaskets, and power valves from Auto Zone that came in Holley packaging blister packs. Have seen Holley parts at O'Reillys. You might be able to procure needle and seat locally. These places also get ordered parts as quick as overnight.

[Michael M.]

Re: '67 Holley Problem

Thanks for the replies everyone.

[Timothy B.]

Re: '67 Holley Problem

Michael,

Could the fuel leak be from the plug on toip of the primary float bowl? Sometimes these things leak and people use epoxy to seal them. I believe the ethonal gas eats the o ring inside so I'm told.

Be careful with the aerosol around the paint..

[Michael M.]

Re: '67 Holley Problem

Michael,

Could the fuel leak be from the plug on toip of the primary float bowl? Sometimes these things leak and people use epoxy to seal them. I believe the ethonal gas eats the o ring inside so I'm told.

Be careful with the aerosol around the paint..

Tim - if the plug on top of the bowl was leaking, I would think it would leak all the time (under pressure) and not intermittently? Do you know if the plug or cap can be replaced - it looks like a swaged fit?

[Timothy B.]

Re: '67 Holley Problem

Michael,

I have never tried to replace one, I think the float bowls are still available from holley. IMO if it's the plug, change the bowl and don't fool around with a hot motor and gas.

You could also try one of the better known rebuilders for a suggestion on how to repair. Whatever you do don't throw away the original part even if you replace the bowl.