11-25-2015, 03:28 AM | #1 |
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Join Date: Oct 2015
Location: hinsdale,ma
Posts: 200
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backfiring
i just got a doodlebug that was given to me running. engine numbers come back as a '28. it runs fine until it gets hot then starts some pretty good backfiring. it has a Mallory dual point in it. there is no inline resistor in it. new points and condenser. question is do you think it needs a resistor in it and how do you tell if the coil has a built in resistor. the coil is old that's on it. (maybe the problem ? ) it has an 8 volt battery in it also. thanks for any help.
Last edited by twostickmutt; 11-25-2015 at 03:54 AM. Reason: forgot to add something |
11-25-2015, 04:13 AM | #2 |
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Location: Australa Melbourne
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Re: backfiring
To check the coil measure the resistance with OHM meter on the primary side
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11-25-2015, 08:08 AM | #3 |
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Join Date: May 2010
Location: Long Island, NY
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Re: backfiring
Backfiring causes:
> Faulty condenser; > Excessively lean air-fuel mixture; > Leaking intake valve causes backfiring through the carburetor; > Leaking exhaust valve causes backfiring through the exhaust pipe; > Heavy deposits in one or more combustion chambers can act like a glow plug and cause detonation while a valve is open.
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Bob Bidonde |
11-25-2015, 09:03 AM | #4 |
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Re: backfiring
8 volts will be harder on the coil, points, and starter. 6 volts works fine. I don't know why they thought it should have a dual point distributor, especially on a doodlebug.
Where are you located? Is the engine enclosed with the full hood? How hot does it get when it backfires? |
11-25-2015, 10:27 AM | #5 | |
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Re: backfiring
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