Do any components need to be changed after a 0.125 overb

I have a 1945 JD A all fuel.

A couple years ago I pulled the engine apart and notice some pretty bad pitting in the bottom of the cylinders. I purchased the largest overbore kit which was 0.125. Since I've had it rebuilt, I've also replaced the carb, mag, plugs, and wires. The tractor has always been hard to start, but it's even worse now. Should I be running different plugs from the factory recommendation?? Should the carburetor be adjusted or changed?

Mag or distributer ? Electric start ?

The hard to start idea needs more information for good advice. What is the condition of the battery? is it spinning well when being started? Does it have fresh
gasoline? Is the spark strong? Points setting? Jim

Several factors can contribute to hard starting.

The mag, can you hear the impulse function clacking while cranking? If it's
not, there won't be enough spark at cranking speed. Have you checked the
ignition timing?

What kind of wires did you use? Mags need wire core wires, not resistor,
especially not carbon wires.

Since the rebuild, have the valves been set? Always a good idea to retorque
the head bolts and set the valves after the first run up to temperature.

Is the air cleaner properly serviced and free flowing? They can be internally
clogged with dirt or mouse/bird/mud dobber nests. So can the exhaust.

The carb should be adjusted last after everything else has been checked out.
The carb needs to be properly functioning, not flooding, be supplied with
plenty of fresh, clean fuel, no vacuum leaks, choke and governor linkage
properly adjusted and working.

Once running, look and listen! Balky and weak usually means too lean.
Blubbering black smoke is too rich. With the engine up to operating
temperature, idle set as slow as practical, adjust the idle mixture for best
idle. To adjust the high speed, idle the engine down, turn the high speed
adjust in 1/4 turn at a time, open the throttle suddenly. Listen for the
response. Keep leaning the mixture, repeating the test until it lean balks on
quick acceleration. Then start backing the mixture screw out 1/4 turn at a
time until the engine will take sudden full throttle from idle without
hesitation. A touch of black smoke is good, it should clear up as soon as the
engine comes up to speed.

As for the plugs, once everything is properly adjusted and some up to
temperature running, preferably under load, the plugs can be 'read'. Look at
the inner insulator, if it is brown, the plugs are in range. if black, they
are too cold, white is too hot.

Again, everything works together. If any one thing is neglected or out of
tolerance, results will vary! If the engine has been run rich, the oil may be
contaminated with gas. That will change the carb adjustments and plug color.
Change the oil if in doubt.

By "hard starting", do you mean cranks over without firing up, or that it turns over hard? If the latter, are you opening the petcocks when you try and start it? That makes a lot of difference.

I like using CHAMPION 589 {W89D} plugs in my two cylinder JDs. Its a hot plug and protudes deep into the cylinder. Generally, it doesn't
carbon up as bad nor does it foul out when shutting off the engine or flood as easy when starting. I have also found that JDs two cylinders
hand start the best when you run them out of fuel to shut them off the prior use. Mine seem to flood easy when hand starting.

I pick up the CHAMPION 589 {W89D} spark plug from Rockauto.com They are about $10 each.

(quoted from post at 18:23:27 08/25/22)
Mag or distributer ? Electric start ?

Click to expand...

It's a mag, and it's a hand start

TRy this. Open the petcocks, close the choke. Turn flywheel until it comes up to
compression, then turn backwards to comp. , then forwards again to comp. Open the
choke & turn it over . When the mag snaps it should fire up & run. You may need to use
a little choke to keep it running at first. Let me know if this works or not. If not,
the mag is weak.

It has a brand new mag, plugs and wires. I timed it all by the book. I usually do 3/4 choke until it pops, open the choke and usually takes off. The problem is it takes like 50 spins before it goes. I'm usually dead by the time it starts.

Try my method with full choke. Don't ever let it fire with the choke on.