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Did head gasket job, tried to start - backfire through carb. Thoughts?
I overheated my 22r, forcing me to do a head gasket. Timing chain is a year or two old, guides are good. It's a trail rig and has probably gottan less than 500 miles on it in the last few years.
I didn't pull the timing chain, but zip tied it all together, went over the whole thing with a fine tooth comb, turned on the propane and went to fire it up.
It cranked a few times, then BAM - backfired through the carb.
I had the motor at TDC with the distributor pointing at the the #1 wire, but didn't know where to set the timing, so I put the distributor halfway between retard and advance. Is this a simple timing issue, or something worse?
Is it possible that my chain shipped a tooth somehow when I did the head gasket?
This is my first time really ever tearing into a motor, so if anyone has any tips, just pretend you're talking to a 5 year old.
Thanks!
Forgot to mention: I rebuilt the rocker arm assembly and relashed those. Is it possible that a rocker arm isn't lashed properly - thus a valve not opening as it should? I lashed them at .008 and .012 per FSM.
The usual suspects when this happens are: (in no particular order) timing, plug wires in wrong order, maybe one other thing I'm not recalling. Check your manual for setting the initial timing. Once you've double checked they are correct - check again. The chain could be off a tooth - how tight was the zip tie when you did that?I don't have a manual in front of me but your valve clearance numbers look off. - someone else here should confirm.
Yes - valve numbers are off in original post...I typed them up wrong. It's .008 and .012 is what I set them at.
It is a propane motor and I set the initial timing at 0* per the FSM as well. I've seen that intial can be as high as 15-18* on a propane motor. I think that might be my issue...
I'll see what I can find on setting up initial timing and try it again. Thanks
Engines run like crap at 0 degrees initial. If the timing recommendation is 5, 10 or whatever advanced, set that at the balancer first, then stick the disti in, rotor pointing directly to #1 on the cap and you will be good to go.
To ensure you are on the correct stroke, as you turn the crank watch the #1 intake valve open, then close, then bring the balancer timing mark up.
Last edited by Melrose 4r; 08-31-2017 at 08:08 AM.
I currently have the Manifold Vacuum...or Idle Advance hooked up to the propane carb. Would that be causing an issue? I have the normal advance capped off and have never used it.
I got the motor back to TDC, bumped the timing to 12* and it's running. I advanced it as far as I could, but I still need a few more degrees. Going to have to bump timing one more time.
08-30-2017, 04:40 PM
