860 back fires

KLuker · Jun 14, 2011

My ford 860 seems to back fire when I turn it off. I turn the power/ gas down but it stills backfires. Does any one know how to fix.

souNdguy · Jun 14, 2011

have you dinked with the timing any?

what plugs are you running?

what fuel do you usually run in it?

important one here... is it 12v /does it have an alternator .. specifically a 3 wire unit using a indicator lamp instead of a diode as isolation from the ignition?

soundguy

KLuker · Jun 14, 2011

I just bought it about a month ago and yes it does have 12v with an alternator. Plugs could be old, but I have not touched the timeing or the carb.

souNdguy · Jun 14, 2011

try this first.

before you shut the tractor down, unplug the line to the #1 spade terminal.

then shut down.

if no backfires, then the isolation lamp is too big and is letting the alt power the ignition a bit still at shutdown.
if that fixes it, I'd install a diode before the lamp.. striped end toward the alternator.. use on at least 50piv and 1a though 200piv and 3a is best. 1n5408 should be very suitable..

if that's not it.. check to make sure you are not running a bit lean.. and also check what plug numbers you are running. might be deiseling 1 hit or so..

soudnguy

awhtx · Jun 14, 2011

Let it run at Idle for a minute or two before you turn it off.

Dean · Jun 14, 2011

Adjust the idle down to 400 RPM or as slow as you can and allow the engine to idle for a few moments before shutting it down. Also verify that the carburetor mixture adjustment is not overly rich.

Back-firing is caused by unburned fuel igniting in the exhaust system. Back-firing upon shutdown is usually unrelated to dieseling. If the carburetor is in reasonably decent condition, the throttle adjustment is returned to idle before shut down and the idle is not excessively high little unburned fuel can enter the exhaust system upon shutdown.

Dean

Hobo,NC · Jun 15, 2011

(quoted from post at 01:09:25 06/15/11) My ford 860 seems to back fire when I turn it off. I turn the power/ gas down but it stills backfires. Does any one know how to fix.

Pull the coil wire to shut it off,,, if it still back fires its running to lean are hot,,, a lean mix runs hotter than a rich mix... EZ enuff to do ...

Try the let it idle tip,,, if that helps its running to lean and hot... It would be rare to see it pop from running to rich... turn the fuel up not down... My mower will pop about the time you get 10 ft away from it after a hard long run of a hour are so... let it idle for 30 sec gives it time to cool down no pop...

I have never seen a backfire from a over rich condition unless their was a ignition problem... try the ez stuff first...

old · Jun 15, 2011

Bet you have hot spots in the engine/manifold from carbon build up so when you shut it down the engine spins over a few turns which is turn sucks gas in that out of the engine and the hot spots light that gas up. You can try this to see if it helps. Put a quart of ATF into 2 or 3 gal. of ga and run it. The ATF will help clean out the carbon build up if that is the problem if it is not the problem it will still not hurt any thing

860 back fires

KLuker

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souNdguy

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KLuker

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souNdguy

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awhtx

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Dean

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Hobo,NC

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old

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