VH 253 motor help

[VPWAGZ]

Hi guys,
i have a problem with my 253, when i shut the motor down sometimes it still half runs then shuts down for a few seconds up to 8seconds sometimes.
i currently have the timing set around 8Degrees advance but am at a loose as to why its doing this, any help would be awesome.

Cheers Jase

[ari666]

check or change your spark plugs first. make sure they are the correct heat range and gap (5 heat for ulp 6 for LPG 1.5mm gap) then check your carby float level.

its called 'run-on' if you wanna google it. usually happens from crap timing, carby out of tune or a buildup of carbon in the cylinders causing ignition via another source. (kinda like a diesel engine)

[VK SL 3800]

And can be extremly harmful to your engine, specially if she starts to run backwards, yes its possible! Probably build up of carbon in the combustion chamber, it glows red so hot it ignites the fuel instead of the spark plugs. Do all as said above, run some premium through it, pretty sure there is some sort of additive to help clean out carbon. If its really bad buildup you may have to try some water down the carby to try and clean it out, sounds crazy but it works. Just a little bit at a time dont go crazy or youll hydraulic lock it and break stuff. Im unfamiliar with the carby on those 253s, later 6 cyls have an anti dieseling solenoid and 308s have a solenoid to take throttle back past idle to help prevent this as well.

[mooseboost]

Does your car run a factory quady? If so it should have a 12 volt idle solenoid on the passenger side. This solenoid is used to set idle speed, not the screw located lower on the throttle plate. When the ignition is turned on 12 volts activates this solenoid to through out. You have to move the throttle to let it come out and lock in. It has 1/4" adjusting nut on the end to adjust idle. When the ignition is turned off the solenoid retracts shutting throttle plate completely, this stops your engine running on. Check if this solenoid is working correctly, back lower throttle plate screw off, set your idle through solenoid and this should fix your problems.

[mikee]

check timing..thats what it was for me in a 202 torana with same problem