TO-30 missing

Hi,

Went to rescue a TO-30 I had loaned out and
no start. No spark. Points looked awful.
New points and condenser and it starts and
runs fine for about a minute and dies. 6
volt z129.

However it dies strangely. It runs on what
sounds like.one cylinder and dense brown
black smoke pours out of the stack. Stop
the engine and it starts right up firing on
all four cylinders again, for a minute.
Then it misses again.

The coil and wires are recent. The spark.is
1/4 inch and white. The fuel flow is
present but not gushing. I pulled the carbs
and did a quick teardown, all was ok. I had
rebuilt the carb about 2 years ago.

The fuel filter in the carb is fine and I
replaced the sediment bowl screen. I can
drain the tank and clean the in-tank filter
tomorrow... But

I am.mystified. got spark. I suppose I
could check.each plug and wire one by one
but all four fire when it starts. I was
thinking it was unlikely that it could be
fuel making it miss. Changing choke or
throttle.makes no.dofference.

Advice appreciated!

Thank you.
 
Are you running an inline fuel filter? This could be clogged or it is not a higher flow gravity filter but one for a system with a fuel pump. On the bottom of the carb take out the drain plug and see that you have good flow, should be pouring out with the plug removed. May also be a float issue.
 
The black smoke indicated too rich.

Possibly the air cleaner clogged, dirt dobbers, something blocking the air flow. Main jet adjusted properly?

Have you checked the distributor shaft for side play? Possibly the point gap is changing once it starts.
 
I popped the air cleaner tube off.

The shaft play idea is a good one.

I still can't figure out why on earth it would start missing and then be crazy rich one time in four when it hits.

I guess I can pull plugs one by one and see if they are sparking when it's missing.
 
Half a cup a minute may be too slow, there should be a steady stream. If the plug was dry when pulled there was no fuel in the bowl. Chances are you have a dirt in the line and or tank. Check the sediment bowl for gunk. I had a problem with a dirty tank that would let the engine run for a little while, quit, then fire back up fine after a few minutes.

I also agree that you may be running too rich. Idle jet should be about 7/8 turn open.
 
Since it seems to die running rich. See if you can pull the plugs and see which one is rich. Not likely a fuel problem. It seems to be a firing issue. Could be plugs. Had plugs when they fired after a minute or two they would short out. Had new ones do this. Could be condensor or coil. Had some weird things happen to ignition systems over the years.
 
Coil resistance is too low and fried the first set of points into the mess you saw. Now the coil runs, overheats, misfires, shorts out and dies. Misfiring causes the black smoke. Question is, how long before it restarts and runs fine? Instantly, or does it take awhile for the coil to cool down just slightly? Resistance cold is how much? And when warmed up to the dying stage? Try another coil supplier if in doubts.
That's my 2 cents.
Flip side of the coin is I have seen a bad condenser cause misfires in engines also. same principle just no way to check resistance.
 
Excellent idea. Restarts right away. I considered this except it's run fine with this same coil and I think it dies too fast for it to be coil heating. I'll.swap.oit the coil just to.see. I'll.have to look to see if there's N external.resistor.

Have new condenser in.
 
Well this was a new one.

The replacement points were very stiff and the moment the tractor started and sped up they wouldn't close quickly enough.

I worked on the old points with a points file and reinstalled them.and now it runs fine.

Thank you all for your help!
 

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