In article ,
ff wrote:

Nick Hull wrote:

In article , "Glenn"
wrote:



"Nick Hull" wrote in message
...


I feel like a fool for posting this since I should be able to fix it in
my sleep, but I can't. 1983 Kaweasaki Prairie 3-wheel ATV wouldn't
start. After digging into it I found the 3 screws sheared that transmit
starter torque to the flywheel. Fixed that; engine turns, has
compression (50#, admittedly low, likely dirt on valve seats that would
blow out on start since I measures 100# 2 weeks ago). Starter is
turning motor in the correct direction, the intake & exhaust valve
operate in the correct sequence when I turn the crankshaft by hand, The
spark is hot & blue and will jump a .250" gap in air. Timing is not
adjustable but a timing light seems to show a flash at the correct 10
deg BTDC.

I put gas or starting fluid in the spark plug hole and NO firing.

If I try it with the plug just out of the hole I get fire about 3 times
before it runs out of fuel.

If I crank the engine with the hot wire just off the plug I get fire
between the plug & hot wire, so that proves current is flowing thru the
plug gap BUT the engine fires on every stroke so I could just be seeing
the spark at the top of the exhaust cycle.

I have the feeling I am missing something simple & stupid. Tell me what
stupid thing I forgot. Please.


Sounds like Valve timing to me. Or something caused the screws to shear
and
that could have been a backfire which may have caused other damage. A
sheared key on the flywheel/magneto or just displacement of the key.
Are there timing marks you can look at on the crank and cam?



I was so convinced the flywheel key had sheared that I removed the
flywheel; the key was perfect, no displacement. At least when I removed
the flywheel I could see the problem with the sheared bolts on the
starter overrunning clutch.



Check the valve timing and the cam chain tension. If the cam chain had
skipped it would explain the low compression.
A badly clogged muffler can prevent starting too.

Fred

I did check the valve timing, the sprocket marks are all correct and the
chain looks good. I suspected that myself for a while until I looked
inside.

I can feel flow coming out the muffler when I crank.

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