Hello guys
I have a 47 ford truck with the flathead ,and 6 volt system ,my truck starts good when it is cold ,but after I drive it awhile ,and let it sit then it is really hard to start.I had the carb rebuilt a month ago so does anyone have any sugestions?

thanks Bill

 

What exzctly is it not doing in regards to the problem, example symptoms?

 

Hello there
After ,I drive the truck,for a half an hour,then let it sit for a half an hour ,it will turn over real good ,but it doesnt want to start.Sometimes it will start when I pump the gas pedel 10 or 15 times ,sometimes it wont .

 

You know, years ago when I was a kid, I had a '41 Ford that would get somewhere and be hard as hell to start. More than one night I was left high and dry when it acted-up. In fact, I'd have to prime the carb with gas and after it started it was fine. It drove me nuts for a long time and then one day by accident, I don't remember how or why, I found the problem. The problem was that the flexible hose between the copper fuel line and the fuel pump was leaking air slightly around the ferrule when the engine was cranking and killing the suction on the infeed side so that the carb didn't get gas to start the engine. I'd never thought of that possibility. When the engine was primed and started, the rapid pumping overcame the air leak and fed the engine. When the engine evaporated the gas from the carb after sitting, the same problem arose. Try changing the flexible fuel line to the fuel pump and see if that helps. Check for tight fittings in the fuel path to the carb also. Never did the leak show any gas. Only the air was getting into the suction side. Winding the engine with 12 volts will help a tired engine start sometimes.

Elder Rodder

 

Check to see if the power valve is maybe leaking at the bottom of the carb. Does the truck show any sign of running rich, like black smoke from the tail pipe.
After your truck has ran for awhile and it gets hot, the carb float bowl should be full. This should start you right up, providing all is well with other components. You should never have to pump a warm Flathead, this spells almost instant trouble. Then you sit for awhile untile the gas clears, and then possibly foulong the plugs, to the point where they are junk. Again check the power valve, also check the area where the previous member mentioned. I'm sure you will locate something, best of luck and I hope you solve the problem.

 

I had a 65 Van once that had a hard starting problem when HOT. I had previously replaced the fuel pump with a rebuilt one. I was on the interstate in the middle of the country trying to get back to the east coast when I stopped to get gas. It would not start at all any more. I thought it might be vapor lock so I pulled the carb fuel line off expecting to have gas shooting out. Nothing there. Then I pulled the fuel pump off and luckily is was the kind you could unscrew to get to the guts. I found that when it was rebuilt one of the check valves was not even close to seating in the hole it was suppose to be. Took a screw driver and pushed it in and peened over the edges. No more hard starting problem.
But I remember in the olden days vapor lock was a common problem with hot engines starting.

 

Hey 5 star
Yes the tailpipe is BLACK like it is running rich,where is the power valve located at ,and how do you fix it,thanks guys for the help!!!!!!!!

yo Bill

 

First off get someone to check the mixturesettings, if you don't know how to yourself. Then once they are set if they can be, and it still runs rough, and black smoke is comming out the tail pipe. Remove the carb, take off the bottom part and it is located right in front of you. This piece the power valve screws into the carb body, you may have to use a pair of pliers to remove it.
It is usually gray in color and it has a diaphram inside that over the years ruptures. If this is the case replace it, you can usually tell if they leak by drawing on it like siphoning gas, you should not be able to draw air through it.

 

Thanks 5 star for that information,I will be checking that out in a few weeks!!!!!!

yo Bill

 

Back in the early 60's I was given a 53 Ford wagon with a Flathead 8 in it. It had the same problem, it wouldn't start when hot. My dad being an auto mechanic by trade found it was the starter armature dragging the field when hot. We just tightened the mounting bolts and it was fine.

 

i had a 52 f 3 with that problem drove me nuts found when hot would boil the fuel out the carb would have to prime the carb or hope it crank enough to get fuel pump back up to it an old mashinist made me a 1 inch aluminun carb spacer to get rid of the heat never had troble after that with fenollic materials would wok better now day and wouldnt need to be as thick i havent seen any for flatties but they was making them for fe engines on the old t birds