70 hp plenty spark no start

[dreamcatcher]

I have a 70 hp chrysler that won't start. Plenty of spark on all 3 cylinders, a bit of quick start in the cylinders, and fuel/oil spray in the carbs gets it to fire but only one revolution. Cranks good, battery good, all ignition checks ok, fuel in glass bowl under fuel pump, and in lines to carbs. Timing is set according to clymers manual, and seems ok by test methods described in many forum posts, but one kick, a backfire through exhaust and nothing. Any ideas appreciated. Thanks...

 

[bowhuntrrl]

Re: 70 hp plenty spark no start

Check the flywheel key to see if it is sheared. If they aren't tightened properly, they will shear and give the symptom you describe (backfire through the exhaust).

 

[dreamcatcher]

Re: 70 hp plenty spark no start

The timing marks line up properly, "0" on flywheel at "I" on tab, and #1 piston is at TDC, this I would think indicates the key is in place. Compression is 100-90-100, is this low? I also noticed the primer bulb never gets hard like my Merc 402.

 

[bowhuntrrl]

Re: 70 hp plenty spark no start

Anything under 100 psi is low, 100 is borderline but ok.