MF65 Backfireing HELP!!!!! VIDEO

[burnsts]

I'm working on a MF65 for someone, it had been sitting for several years and wasn't running.
I have rebuilt the carb, replaced all the spark plugs, replaced plug wires, changed out points/condenser, i have adjusted the timing and it still backfires?
Here is a link of a video of it running, sorry it's a little hard to here the engine because of the fan.
I also put some automatic transmission fluid down the cylinders, hoping to loosen up the valves.
Is this a valve problem? or is this something else?
Thanks for any information
Untitled URL Link

 

[Gearhead210]

Kinda hard to tell without hearing it in person, but as often as it was backfiring out the carb and it had that "froggy" sound to it, kinda sounds like an intake valve is staying open, especially since it is blowing fire out the carb. Unless the ignition timing is wayyy off, but I doubt it would even run if it were that far off. I would run a quick compression check on it- that will tell you a lot pretty easily. Should have 100psi "ish" when cranking, if one cylinder is way off, then I would check the valve lash. May be as simple as a stuck valve, or as bad as needing the head rebuilt. Hope this gets you started

 

[Andy4020]

try another new condensor, I have been having bad luck with the new ones you get, I havent found a good one yet. I usually end up putting in electronic ignition.

 

[Anonymous-0]

Having the right two plug wires crossed can sound and pop through the carb like that. Something simple to rule out.

 

[john65]

might also be a cracked dis. cap

 

[Anonymous-0]

Go through that ignition, and check everything, again, including firing order. Then a compression test, or three, at various temperatures, times of day, after sitting for a while, etc. Might be a hanging valve, or a bent push rod, or trouble in the valve train.

 

[2tractors]

Sounds like trashy gas to me.

 

[samn40]

make sure your plug leads are in correct order 1,3,4,2
Sam

 

[burnsts]

Thanks for everyone's info, i will recheck the firing order, i also borrowed a compression tester and i will see if any valves are sticking.
I will keep everyone posted.
THANKS

 

[Jerry/MT]

Check the initial timing and that the advance mechanism is working. Hold the choke out a little and see if that cures it. If it does the mixture is too lean or the spark too weak. Check the sparkl and fix or check for air leaks around the metering section of the carb(throttle shaft, intake manifold conection gasket at carb anf cylinder head, cracked otr rusted intake manifold, etc).

 

[Aaron Ford]

Also remember the dizzy spins CCW. I screwed this one up. If you get it reversed just change the 2 and 3 wires to effectively reverse it.

Aaron