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Tom Timmins

Misfiring under load

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I have a 1911 EMF that runs like a watch until you push it a little too much. On an HCCA tour last week there were lots of hills and by the time I reached the top, or even before, the engine would start to misfire and die. After a couple of minutes or so, the engine would start and run fine for a few minutes and then the same thing would happen. It also happened on flat land at higher rpms. Is this a timing or carburetion problem? Any suggestions will be appreciated. Tom

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In two 1920's cars, I had the same problem. Both times it was the sparkplugs! If you are running vintage plugs, I'd bet that's the problem. We tested our old NOS plugs on a rebuilt Champion plug tester. On both occasions, the spark broke up when the air pressure went up...way before they should have. New Champion plugs to replace the vintage ones worked fine and NEVER broke up. Sometimes, big problems can be a simple fix. Check it out and good luck.null

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The fact that it does't recrank almost immediately would rule out plugs for me. I suspect fuel starvation. Check to be sure of adequate fuel delivery.

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Given my experiences with both a 1912 Franklin and a 1912 Renault, my vote would go to fuel starvation, as well. In both cases, the cure was to make sure I pumped the air pressure up in the fuel tank. I could have added an electric pump, I guess, but that didn't seem too authentic. With the Renault, I found I also had to go to a less restrictive fuel filter. No problem since.

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Tom,<P>My first guess would also be fuel starvation. If you experience this only when hot, the gas may be boiling in the float bowl. Our gasoline boils at a lower temerature than what they were using in 1911. If your carburator is all stock, it draws hot air from the exhaust manifold through the third and fourth cylinders. This may be enough to get the carburator too hot, although it may be a stretch. On my Hupmobile, the carburator is right next to the exhaust and this is a constant problem. I choke it a little when I find it impossible to accelerate after sitting at a red light. Check your fuel lines, including the sediment bowl for any obstructions or high spots that may trap vapor and check for gunk at the float needle valve. For that matter, make sure that the float is opening the valve at the right level. It's hard to immagine that gravity isn't giving you enough fuel pressure with a full tank of gas, but a pump may be the solution if that is truely the problem. Good luck, Robb Stewart

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