How to prime the flatty

40Ford!!

40Ford!!

Senior Member
I just replaced my intake and I'm not getting the fuel to draw. I'm quite sure the fuel pump is on properly and the fuel line is not plugged. I blew air from the fuel line up front and there was definitely fuel in the tank. I blew air from the rear and I could not get any fuel to push thru. My next effort will be to add some fuel into the carb and get it to fire. How much can I add directly into the carb? Any other suggestions? Thanks
 
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40Ford!! said:
I just replaced my intake and I'm not getting the fuel to draw. I'm quite sure the fuel pump is on properly and the fuel line is not plugged. I blew air from the fuel line up front and there was definitely fuel in the tank. I blew air from the rear and I could not get any fuel to push thru. My next effort will be to add some fuel into the carb and get it to fire. How much can I add directly into the carb? Any other suggestions? Thanks
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I'd dump a thimble or so in there choke it and see what happens. Sometimes it takes a little to bring it up from the tank and fill your float bowl.
 
I have a fuel shut off and when I park mine for several days I run the carbs dry. At startup it takes 5 seconds of cranking to get pressure at the carburetors. I am interested in how much fuel to manually put in to prime after long shutdown with dry bowls.
 
To push fuel through the system you need to let the air out. After cleaning out the stock fuel filter I would leave the glass filter bowl loose and then blow into the tank. The air in the line comes out the gap allowing the fuel through. A few decent puffs, then around to the engine and the bowl would be filling nicely. Re-tighten before it gets to the top. The electric fuel pump I fitted for starting saves the huffing and puffing.
 
Make sure the cap for the fuel pump is snug, 7/16 hex head bolt on the top. Temporarily place a couple wraps of electrical tape around the bottom of the fuel pump steel cap and the top of the casting for the body. The tape will seal the cork gasket from pulling air when it is dry and once fuel is in the pump the gasket well swell and the tape can be removed.
 
After replacing carb and fuel pump, I place my hand on top of the carb and crank the engine. The vacuum generated simply pulls the gas up to the pump. I watch and see the bowl filling and know then that it will fire up.
 
Uisng an electric fuel pump for those times the car has been sitting long or on a first start after a modification or a rebuild has worked for me .... start the pump, start the car, shut off the pump once the engine is running.
 
Fuel pumps are weakest on the suction side, and with somewhat tired equipment an empty system won't prime even with long cranking even though pump is working well enough to run the car once fuel gets up front...
Best way to prime is to make a small can or use a tiny funnel to directly get gas into the carb bowl...when I was running a very high mileage rig I added a piece of thin tube to the bottom of a small can so I could insert it right into the bowl vent of the carb and avoid dumping raw gas down the engine's throat. The rather weak pump would then do fine once the engine lit.
On later Ford flathead carbs, there is a convenient vent tube in carb throat, on earlier Ford vent holes are external, and on Strombergs the hole is behind the rocker...all require a small tube or hose to prime neatly.
 
Ok, call me a botch artist, but I just tip a bit of gas straight down the carb. It'll fire and run. It will go for a few seconds and after you've done it a few times it will have pulled the fuel through and run on it's own.

One precaution, though, don't stand over the carb with a jug of gas, tip a bit in, go and put it down a little way away from the car and crank it over. Repeat as necessary.

Mart.
 
I agree that starter fluis is harsh but only if you use in all the time because of fuel delivery issue. Safer than gas and wear some eye protection.
 
I do what Mart does.....squirt gas into each carb and it will strart for a few seconds. Do this a few times and it starts up for good. Don't want to use starter fluid on a healthy engine. :)
 
If you are equipped to fill the bowl, the thing can start normally. Gas down the throat means cranking until enough raw gas goes down the gullet to allow a startable mixture, quickly followed by lean-out backfire as the slosh runs out. Once you fabricate something with a tube that will enter a vent, it is at least as easy as just drowning it.
 
I woundt use staring fluid but use carb cleaner with the plastic nozzle that way you can spritz it in to keep it running.do it all the time at the shop.
 
Buy an OPTIMA battery !!!
My all stock 36 can sit for months , I just pull the choke & let the optima spin her over like its 12volt until she sucks the gas from the tank & she busts right off !
No Kenct pump here !!! A correctly rebuilt & tested pump built 9 years ago!!(by me )
Cheers
Tony
 
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