1010 Gas misfires

Ed1010c · Post by **Ed1010c** » Wed Oct 12, 2011 6:27 pm

Have an early 1010 gas crawler. When its cold it starts immediately and runs strong. After the engine has been run for more than a few minutes it starts misfiring and backfiring through the exhaust. If I shut it off it won't start again until I let cool down for a long time (several hours). The engine was rebuilt a couple years ago and does not burn oil. It seems like the time from when I start it up cold to when it starts misfiring is getting shorter lately preventing me from using the machine for anyhing that will take more than about 10 minutes. Has anyone else experienced this or have any idea what could be causing this?

440 iron popper · Post by **440 iron popper** » Wed Oct 12, 2011 7:04 pm

Hi,
Considering that the engine was rebuilt a couple of years ago, there should be no problem about compression, loose valve guides or heavy carbon deposits that cause the valves to not seat properly.

I had similar problem with my 440. Even fire coming off the exhaust stack! Maybe you have an electrical issue. Is your charging system working?

If you can crank it and have it run for a while then it begins to back fire after a couple minutes, I guess the battery drops and drops over time weakening the voltage at the coil. The intensity of the sparks suffers from it. And it finishes to burn the gas in the hot pipe. Then when it sits, the battery voltage reincrease a bit permitting another start and a quick run. Then it comes back... I would put a meter on the battery to confirm it's OK. That was my case along with the engine being worn out...

Advance mecanism, points adjustments, timing, type of spark plugs, weak coil, bad capacitor, bad gas, bad flow of gas... When it comes to ignition problem you have a large choice of causes! Guys on this site have seen them all I guess. You're at the right place!

jtrichard · Post by **jtrichard** » Wed Oct 12, 2011 7:22 pm

sounds like its running lean has it been sitting? could be dirty carb.... turn the main jet out half to one turn and see if that helps

mnwoody · Post by **mnwoody** » Thu Oct 13, 2011 5:08 pm

There are many things that should be checked, I would start with the gas tank vent tube. I have had several pieces of equipment get corroded or mud wasps plug the vents on fuel tanks. They run for a while, start to misfire and then stop. Let them sit for awhile and they fire right up and do it all over again. Good luck.

Vinny Cavaliere · Post by **Vinny Cavaliere** » Fri Oct 21, 2011 4:25 pm

I have seen a bad condenser do that were as soon as it gets hot it will stop working until it cools off. Good luck.
Vinny

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1010 Gas misfires

1010 Gas misfires

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