poor starting av

I have a 1951 Farmall AV. When you push it or pull it the tractor starts and runs fine , however using the starter the engine wont start. I even put in a 12 volt battery and it turns over fast but still wont fire of whats wrong?

Helllo Stormy welcome to YT! It would be helpful to know if
the tractor has a magneto or battery powered distributor
and coil ignition. If it has a magneto do you hear a clicking
sound from it while cranking? Either way I would suspect
you have looked at the points and plugs and they are in
good condition. Does the choke work properly? That
means pull off the air intake and look in there make sure it
is totally closed and the back fire valve in the plate is intact
and closing.

Does it have gas?

Can be several reasons, or a combination of reasons.

Weak spark or no spark when cranking is a common cause. Check the spark while cranking, it should
have a minimum 1/4 inch spark to ground at the plug end of each plug wire, not just at the coil,
but the plug end of each wire. If battery ignition, a defective ignition switch, dragging starter,
too small battery cables, worn plugs, bad or out of adjustment points, a bad/weak condenser, bad
wires, cap or rotor, anything that can deprive or weaken the spark under reduced voltage, as the
starter requires a lot of amperage.

If magneto, you should hear the impulse mechanism clacking inside the mag while cranking. If not,
it will not crank fast enough to make a spark.

A choke that is not fully closing can cause no start at cranking. Try a squirt of gas in the carb,
or hand choke it to see if it fires. If it does, either the choke is not fully closing, or the
choke enrichment circuit in the carb is clogged.

Finally, low compression can cause hard/no starting. Have the valves been adjusted lately? Is there
excess blow by out the breather tube? Poor idle, blue smoke, loss of power? Might run a compression
test, see what you get. Do a dry test, then put a squirt of oil in each cylinder, run the test
again. If a big improvement, the rings are worn. If low numbers and little to no improvement, valve
problems.

Let us know...

(quoted from post at 20:36:31 08/31/21) Does it have gas?

Click to expand...

I hope that was intended to be a joke.