48 Cub still not starting

[Rayman66]

I am still unable to get 48 Cub to start. This is what I have done: New points, gapped at .013; new condenser; New coil; New spark plug wires.
Plugs gapped at .025.
Made sure on top dead center before reinstalling J4 magneto.
When cranking, motor will back fire at least once out of muffler.
"Sounds" like it wants to start (you know what I mean).
Pulled plug after cranking motor over and not a hint of gas on the spark plug.
Any additional help will be greatly appreciated.
Thank you in advance.

 

[used red MN]

You checked for the correct TDC as I explained in your
other post? Every time the piston comes to the top of
the cylinder is NOT always the compression stroke of
that cylinder. It is all explained in my reply in your other
post, see link. Also did you check to see if all cylinders
pushed at least some compression against your thumb
when cranking. If it does than that eliminates stuck
valves. A guy on here used to post under the handle of
..not just air.. take heed.
Previous post

 

[old]

Have you made sure you have a good blue/white spark at each plug that will jump a 1/4 inch gap or more?? A back fire to me say the timing is off or you have a couple plug wires crossed

 

[rustred]

There is 2 TDCs. U need to be on the compression stroke
not exhaust stroke. Thats your problem as I said last
time. And you did not verify that you were on
compression. Glad ur not charging by the hr. Lol

 

[the tractor vet]

welp if it is a dist ing and not a Mag the POINTS set at .020 not .013 that is the points setting on a mag.

 

[gene bender]

backfire means spark isnt in time with compression does the rotor line up
with the tower when it fires try the old condensor new can be bad and clean
the points remove #1 plug with wire attached and plug grounded now turn the sw
on put your finger in the hole have someone hit the starter you should see
spark at the plug when engine hits compression stroke thats the easiest way
to see if #1 you do have fire and #2 is the spark in time with the engine

 

[Charlie M]

I'm thinking if the plug is grounded to the tractor and your finger is in a spark plug hole you are going to find out real quick if the plug fired. I did something similar once with a mag sitting on the platform of my H, I turned it by hand and when it fired my leg was against the drawbar. I'm not doing that again.

 

[grandpa Love]

Welcome to call anytime. 256-404-
zero123. Happy to help, sure
sounds like a timing issue.

 

[teddy52food]

Switch all the plug wires across from where they are now in the cap & try again

 

[Keith-OR]

I read your first post, you said it was back firing out both exhaust and intake. You were given lots of good suggestion on fixes.
So now you have did most everything you were suggested to do, and still can't get the tractor to run. No gas on plugs, back fires out the exhaust, tires to run, hhhmmm. sounds like no or very little compression, possibly couple of valves could be stuck open..
No compression, you will have no vacuum to pull fuel up into cylinders. DO a compression test, if you don't own a compression gauge you can borrow one from either Auto zone or Oriely's auto parts.

Keith