Empty Carb Float Bowl

[Byron Warwick]

I've hads trouble with my carburetor float bowl drying out after 2 days sitting in the garage; !934 Pickup, 1954 8BA engine, '94' carb. I changed the power valve after talking to KenCT, but it still happens. Any other suggestions. No problems starting after a day and a half, but the next day it is a long starter grind before it fires. I've left it on the workbench for over a day and there does not appear to be any leakage. Modern lighter gasoline? Byron

[DICK SPADARO]

Welcome to the New World Order, this problem will persist forever now with the newly formulated ethanol diluted fuels. Between the air temperature and engine temperature the carb bowl storage design does not lead to evaporation protection so the new fuel just evaporates away in this type setting. The new fuels are best suited for high pressure fuel injected engines thus making your car hard to start after setting unused for 2 days or more beause the storage bowls have dried out. Some people have band aided this issue with the use of electric fuel pumps to aid the slow priming original pump or just use a couple quick blasts from a starting fluid canister to aid the engine to life after an extened rest period. You think your car starts hard now wait until you get e85 rammed down the customers gas tank.

[37fatfender]

Are you sure it is not siphoning back thru the fuel pump? I find it hard to believe it evaporating in 2 days. If its not leaking from the power valve sitting on the bench and its not getting past the accerator pump????. My quess is the fuel pump. My car often sits for more than two days and starts.

[oldford2]

Siphoning back?? Please explain the path. I could never understand how this can happen. Evaporation?? I have an engine on a test stand and the accelerator pump always squirts after sitting a week. You have a leak somewhere. Maybe the power valve seal?
John

[Ronnie]

I will listen to siphoning story also

[1952henry]

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They can't siphon since the bowl is vented.

[G.M.]

It can't syphon back from the carb because the inlet hole is near the top of the bowl. If the needle valve was open it can only syphon the gas from the fuel line and not the bowl. If the needle valve was closed it can't syphon this is like putting your finger over a straw with soda in it but the bowl has to be filled to keep the needle valve closed. The valves in the fuel pumps are poor even at their best. Read the Ford service manuals they say if you put a gauge on the line between the fuel pump and carb the say 3 lbs pressure should not leak to zero in less then 1 minute. Not very good check valves. I have one of Bob Shewmans ([email protected]) new flex hoses with a check valve built into the fitting on the pump end and have a low pressure gauge installed with copper tubing and the fuel pressure stays between the pump and carb for at least a week. I haven't let it sit longer so I don't know just how long it holds. If gas is available in the pump and not drained back to the tank the engine if tuned properly will start up in 2 or 3 turns from the gas in the pump even if it evaporated from the bowl. I can reach in the window and touch the starter button and it starts on the first turn. G.M.

[GITCHIGUMI]

I agree with Oldford2. the powervalve itself is probably ok, however if you are not using the correct gasket/seal between the valve and the carb or the PV is not installed tight enough to make a good seal, it will leak. I have had similar problems when installing a new PV. To check if it is the seal or PV, take the bottom and the top off the carb so you can see the PV and add gas into the float chamber. If either are leaking you will see the gas run out around the PV.

Guitchi

[Karl Wolf]

My personal theory is that a hot engine cooks off the fuel in the carb... Karl

[G.M.]

His post said he put fuel in it and left it sit on the benchover a day with no signs of a leak. That should eliminate the power valve or it's gasket. G.M.

[41ford1]

I have to agree with Dick Spadaro. This corn gas evaporates faster than the straight stuff from the past. Smells different too. After 4 days the bowls are empty. I have verified there are no leaks in my carbs. It will be worse when more alcohol is blended in. The solution for priming may be installing an electric pump. Right now I use a small squeeze bottle to prime the carbs though the vent if the truck sits for any length of time. To overcome this situation I think I need to drive it every day. LOL

[JT FORD]

I have the same trouble after a week of setting. It will help to shut the engine off and pull the choke out. This will help to get a few more days before the fuel is gone.