Carter W1 empty itself quick

[patallen]

Hi, my carter W1 with new rebuild kit empty itself after 1 day. There is no external apparent leakage like it used to before from the large brass plug under it.
Where the fuel goes ? could it leak from the idle jet down into the intake ?

Fuel filter stays relatively filled so gas doesnt return to the tank. It cant anyway i know.

Thanks for any inputs !!

[patallen]

nevermind, i inspected it all for the nth time, and found another leak from one of the tiny copper inserts/plugs.


thanks.

[Phil Waterman]

Hi
Diagnostic questions:

When you say empty how do you know?

I've got electric fuel pumps on all three of my CMPs and when you turn them on you can hear the pumps fast click until the carb is full and line is pressurized. The pumps almost always run for several seconds up to 30 second if they have been parked for more than a few hours or over night or a week. They will also run if the truck was shut down hot fully hot even if it has sat for only 15-20 minutes.

Can you see fuel in the manifold?

If you think it is leaking internal down the throat have you tried running the engine with the engine cover off and the air cleaner removed. Shut the engine off pull the hand throttle out full or block the throttle open, try not to pump it more than once. Look down the throat with a flash light and see if you can see fuel running in and if there is a puddle of gas in the manifold. Let the truck sit for awhile and keep checking it.

If it was me and I was going leave it overnight I'd put a note on the ignition switch reminding myself that the throttle is blocked open. I hate it when I start the engine at full throttle.

Let us know what you find.

Cheers Phil

[patallen]

i know because i opened the carb after the truck sat for lets say, 1 day.
Fuel bowl was almost empty, level was below the main jet.

I started to make diagnosis and test once i found the truck was not easy to start, always took a while, almost emptying the battery all the time. This is like that since i brought back the fuel system up to "factory" spec, ie, working oem fuel pump, por-15'd tank and lines.

Before i was using a gas can straped to the top of the carb and everytime we used the truck and after we took it out so we never noticed that the carb was leaking like that once it sat for a while. You can see this red neck fuel system on most of our videos on youtube. Thats it.

As i said, i found the source of the leak. I try for now some rubber o-ring since the new copper ones hasnt done the job quite well 3 times.

I also reduced the size of the jet, from 0.100 down to 0.092, the truck was running 11.2:1 afr under acceleration, (not idle)(measured with my wide band oxygen sensor). Now it is near 12.5, much better....

[patallen]

where is the hand throtle located usualy ?

our truck dont have an engine cover...for now.

thanks.

[Phil Waterman]

Hi

The Hand Throttle and Choke are operated by slide cable from the dash. These pictures show how they connect to the carb



For higher resolution photos go to http://canadianmilitarypattern.com/R...mera%20045.jpg
and
http://canadianmilitarypattern.com/R...mera%20046.jpg

More engine photos from my HUP project http://canadianmilitarypattern.com/H...INE%20WORK.htm

Glad you found the source of the fuel leak, the slow priming is one of the reasons I have gone over to electric fuel pumps. Was very interested to hear that you are using some high tech tools to tune the engine. You will have to tell us more about this as your project progresses.

Cheers Phil

[david moore]

I have the same sort of problem as mentioned here - my jeep is very slow starting after being left even for an hour or so. I can help it with a spritz of gas into the top of the carb (its a Solex in this case).
I'm wondering if the fuel cap is supposed to have an air vent? Mine doesnt. My logic is that, if sealed, there will be a partial vacuum in the tank after running - which could suck back fuel to the tank. Or is this not possible?

Or could it be that the timing is a bit off? I never know if it needs to be a shade more advanced or retarded for easier starting. I also dont know which way to turn the distributor head a little for advancing or retarding.

Comments welcome!

[motto]

Fuel cap venting has been a topic of some discussion over the years and is often misunderstood. Basically, a fuel tank cap must have venting unless the venting is provided elsewhere. Having said that, the fact of the matter is that on a hot day no venting is needed as the fuel vapour will pressurise the tank anyway. After all, a LPG cylinder does not require a vent to expel it's contents, vapour pressure does that. The difference is that LPG vaporises at a much lower temperature than petrol.

I once put a jerry can in the sun and it went up to 3 psi which is fairly close to fuel pump pressure. The standard WW11 4" cap used on GMC, Jeep, etc. had a relief pressure of around 3 psi and this was not without reason. On hot days, this pressure in the tank helps prevent vapour lock which, as we know, can immobilise a vehicle.

Cold conditions are a completely different ball game. We've all seen jerry cans with the sides sucked in that had been filled in warm conditions and then subjected to cold. Your fuel tank will do the same if not vented and this is made worse if fuel is being removed from the tank. For this reason, those 4" caps that have the 3 psi outwards relief also have (if I remember the figure correctly) 1-1/2 psi inwards relief.

In summing up, for cold climes, a simple vent hole in a cap is sufficient. For hot climes, a pressurised tank through use of a relief valve is a definite advantage.

David

[patallen]

given the short time you mention that the jeep is reluctant to start, i would say, from experience, vapor lock. it wont be the first time i hear about fuel boil into the carb on a jeep once stoped after a ride.
fwiw make sure there is a heat insulator under the carb to isolate it from excess heat.