Troubleshooting WC51

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G. Miskovsky
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Troubleshooting WC51

Post by G. Miskovsky »

Hey all,

Been having some problems. Crank the engine with no trouble, revs good. Take it out and after a quarter mile she dies out under load. Idles fine but when I give it throttle she wallows, let off the the throttle I get a good idle.

If I turn off the engine and crank it again I get about a minute of power then she starts to loose power, again I let off the throttle and no problem. Messed around with the distributor advancing and retarding...no joy.

Any thoughts?
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Gus

'42 WC-51, '43 Ben Hur
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Gordon_M
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Re: Troubleshooting WC51

Post by Gordon_M »

One thought.

Start her up and then run a wire from the battery straight to the coil, see if she still does it. Replaced the condenser recently? Many new ones are crap.

If you can rule that out then fuel delivery. Collapsed / collapsing fuel hose internally, crap in fuel filter or carb
Gordon, in Scotland

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G. Miskovsky
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Re: Troubleshooting WC51

Post by G. Miskovsky »

Thanks Gordon,

When running a wire to the coil...positive to positive I assume.

thanks
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Gus

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Re: Troubleshooting WC51

Post by Gordon_M »

Pretty much, I'm aware that some trucks were positive earth and some negative, so whatever.

Basic principle is to rule out that something is stopping electricity to the coil and thus strangling the spark. Once that is ruled out it is the fuel system.

It'll be something small, easy to fix, cheap, and difficult to find. Collapsed fuel line, blocked filter, or blocked carb are favourites. :D
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Re: Troubleshooting WC51

Post by Ray Edsall »

G,Day Gus . Many years ago we had a similar problem .Idles ok ,but when you rev it, it stall,s, lose of power . We eventually tracked it down to a bafffle in the muffler had broken off . Idled fine but when you excellerated the loose baffle blocked the out put hole .So there was a build up of exhaust in the muffler ,thus the exhaust gasses could not escape through the muffler and out . Try taking the muffler off . See if this fixes the problem. Just a thought . Ray
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Re: Troubleshooting WC51

Post by PareosWC »

Gus, is this something that has occurred "all of a sudden"? How often are you driving her?

Initially, this sounds like a fuel delivery issue under demand. Starts and idles well tells me that the condenser and coil are satisfactory, and that your idle circuit is working ok. Once under load, the idle circuit is no longer needed, but more fuel is needed, but the high speed circuit sounds plugged and cannot deliver. If it were the coil or condenser, I am not confident that it would even start.

I place my hypothesis on the fuel system- pump not pumping enough, or circuits are slightly plugged.

-OB
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G. Miskovsky
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Re: Troubleshooting WC51

Post by G. Miskovsky »

Thanks Ray I’m going to give the muffler a go over then the carb.

OB, thanks for the reply, I too was thinking of blowing out the high speed jet. It might be that something has clogged the carb being that it seems to stutter as if it is not getting enough fuel.

Thanks guys
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Gus

'42 WC-51, '43 Ben Hur
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G. Miskovsky
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Re: Troubleshooting WC51

Post by G. Miskovsky »

Update,

Took the carburetor off yesterday and found the Vacuum piston and step-up piston both stuck!

test drive this weekend!
AIRBORNE ALL THE WAY!
Gus

'42 WC-51, '43 Ben Hur
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Re: Troubleshooting WC51

Post by PareosWC »

Nice! Congrats, Gus.
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Re: Troubleshooting WC51

Post by motto »

Your initial problem of losing power after a short run sounds like a blocked vent in the fuel tank cap or an incorrect non vented cap has been installed.
With no tank venting and a full tank of fuel, particularly if the ambient temperature is low the pump will cavitate and the engine will starve.
If you leave it stand for a while the pressures equalise and the engine will be good for another short run.
If what I suspect to be the case is what is in fact happening you can check it out by removing the filler cap when the engine falters and there should be a definite inwards rush of air.

David