Rebuilt Farmall Cub has Fire but won't start

[Briggsman4188]

On this tractor, topend of motor has been rebuilt. It has new rings, pistons, rods, valves, valve springs and carburetor. Valves have been ground to match the block and still won't start. I have 30 lbs of compression. When I put oil on top of the head I do get 50 lbs of compression. I did a vacuum pressure test on the valves and I get 29 psi with no springs in it. (Just pushing them down with my fingers) I put it all back together and still won't run. So I put new rotary button, distributor cap and points. I have plenty of fire but it just will not run. The carburetor wants to flood. This is a 6 volt tractor. I pull it off with another tractor and it will crank but dies.

Does anybody have any idea on what's going on? I thought it might be the timing so I checked that and it is top dead center and the pointer is pointing straight to the mark on the flywheel. That means it is not out of time.

Sidenote: This tractor was brought to me by a lady who advised the tractor had been sitting for a long time. Because it belonged to somebody else and it's been sitting for so long I'm not sure what else could be wrong with it that may possibly be causing me additional issues.

Any ideas, suggestion or help would be greatly appreciated. I am about ready to throw this thing into the pond and use it for an anchor! lol

 

[ovrszd]

Sure sounds like carb issues.

Compression seems low as well. Valves properly adjusted I assume.

I start with simple and go from there.

If it's flooding the plugs should be wet after a couple attempts.

 

[skipperbrown]

As a chainsaw mechanic once told me: It's either foo or fur. If the plugs are wet you are likely getting 'foo', although maybe not the right amount or too much. If there is a spark you are getting 'fur'.

Are you absolutely sure your timing isn't off 180 degrees? I once had a MGB and it was possible to insert the distributor one of two ways. One way fired the plug at the wrong time and the engine wouldn't start. Ask me how I know that.

Next, are you getting a spark across the plug? A painful way to tell is to hold the plug wire while you crank. As me how I know that.

Next, do you have the right firing order? How do you know?

Maybe and carefully spray some ether and see if it fires.

Report back after confirming and we'll try something else if it doesn't work.

 

[Briggsman4188]

 

[Briggsman4188]

i had it running after i got back together but it quit and the carb has fuel coming out the weep hole and now it just wont start at all has only 30 lbs of compression if i put oil in the cyl it will run again i know it s the low compression not pulling the gas up the intake but if i pull it off it will fire and run a min the reason i dont think its the timing it runs to well when it ran i can pul two wires off and it will run as well when it was running the valves are set at 015 i thought about going up a little to 012 what you think i just have to pull the side cover again

 

[ovrszd]

Sure sounds like a carb issue. Low compression might be caused by rings washed down with gasoline. Plugs wet?

 

[Briggsman4188]

yes right fireing order i have worked on several tractors im a mechanic too just try ing to get some ideas of what other mechanics thinks whats wrong i know its compression but it all new im allmost thinking about pulling pistons again and checking rings but everytime i get ready to do that the thing crank and runs for a bit and dies again i thought it might be the fire so i took my plug wire and hook up a checker where i can see it fireing in the glass and when it dies it had fire till it died and when u ccrank again u can see the fire in the glass so it s not the fireing

 

[Briggsman4188]

yes the plugs getting gas the funny thing is it wont fire from ether i wondewr is it the ethanol in the gas is my problem u know this tractors didnt have ethanol running in there days

 

[ovrszd]

As a mechanic you understand the things involved. You've convinced me you've got fire. Now convince me the carb is properly functioning.

Plugs wet?

 

[Briggsman4188]

yes the plugs getting gas the funny thing is it wont fire from ether i wonder if it the ethanol in the gas is my problem u know this tractors didnt have ethanol running in there days