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'23 runs great, then it doesn't


Scott S

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My '23 four cyl. roadster has been running great. However, when I was out the other day, it would not start again after being shut off after a drive. After a tow home, I eventually figured out that it was a spark plug problem. I think the plugs were wet with fuel and would not fire, however simply waiting a few days did correct the problem. Since the plugs looked pretty old, I put new ones in and it fired up instantly.

I went for another great drive and then when I shut it off, I could not restart it, even after only a few seconds. I think that the plugs must be getting wet. Anyone ever have a similar problem? Suggestions?

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There is an old problem with carburetted cars. It's called "purcolation". That's when the hot engine causes the gas in the carburetor to boil and "purcolate" into the intake manifold, and then to the plugs if it is bad enough. It is quite common when Summer driving in cars with downdraft carburetors. It could also be a stuck float causing the same condition. In both cases you'll probably smell raw gas coming from under the hood.

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Since you have an updraft carb. I doubt that percolation is the problem.

Check the plugs to see if they are black. If so, just clean them and lean out the mixture a bit and try again. Also use a hot plug to help prevent fouling. I use Autolite 3077 or 3076 plugs. You can also get Champion W18 plugs at your local John Deere Tractor store. They stock them for older tractors.

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Thanks. The first chance I get this week I will pull the plugs. I have brand new W18's in there, but I suspect they are fouling. I recently re-adjusted the carb and the needle valve is only open a half turn, which I believe is the recommended initial adjustment. It ran so strong before I shut it off that I was afraid to touch the carb again. If they are fouled I will close the valve another touch.

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I concur with Mark Shaw, in fact, until I learned the 'habits' of my engine I had similar poor hot re-start issues. My poor starting hot/warm was related to the fuel petcock and forgetting to close it if I parked for more than a short period of time. If I remember to close it and then open it for the re-start, the engine starts on the first rotation. If I let things leak out, it's a bear to start hot. The magic time period for my engine is about a half hour. Any stop longer than that and I need to shut the valve to get a good re-start. My carb does not leak while running but is does drip into the little pan when not running.

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I learned very quickly how important it is to shut off the fuel when parking the car. When I first got the car, I got worried when a little fuel dripped into the pan after shutting it off, but I think that is not a problem. In this case, I tried to restart just a few seconds after running. I am now pretty sure that it is a spark problem. I have not had time this week to pull the plugs again, but I cannot imagine that I could have fouled new plugs with a ten minute drive.

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