TO 30 Will not run unless choke is pulled

Kadbow · Feb 27, 2018

Been working on a new to me TO 30. Got the axle and pto leaks taken care of and moved on to what I thought was carburetor issues. When I first bought it the tractor would run fine for 5 to 30 minutes then start running rough. I would mess with the the main jet and it would run for awhile again and then run rough. I thought there must be junk getting into the carb from the tank. I flushed out the tank, put a new sediment bowl on, flushed out the fuel line and cleaned out the carb. Now it only runs with the choke about three fourths out but with the choke in the right spot it runs good. It has a zenith carb on it. Any ideas?

RM-MN · Feb 28, 2018

Check the quality of spark. A worn out set of points will get you a weak spark that cannot jump the spark plug gap when there is a full charge of air and feul but by choking it you reduce the charge and richen it. A good set of point should get you a spark that will jump a 1/4 (or more) gap with a blue-white spark. If the spark won't jump that gap or has a reddish spark, replace the points.

Carolina boy · Feb 28, 2018

I had this happen many times with my TO30. My money is that you have small impediments in your carburetor. My fix was to remove the carb, squirt wd40
or pb blaster into the jets, then blow them out with a a compressor. I then installed an inline fuel filter from NAPA. Haven't had a bit of trouble
with it since. Good luck, God bless.

Jeremy in DE · Feb 28, 2018

(quoted from post at 09:47:54 02/28/18 ) I had this happen many times with my TO30. My money is that you have small impediments in your carburetor.

I had this same experience. In my case I cleaned the carb and the passages carefully. (I thought.) A couple times. I was confident it was clean and the problem elsewhere. But I couldn't find it elsewhere.

So I cleaned the carb "one more time". And bingo problem solved.

Of course, this is certainly no guarantee your problem is in the carb. Certainly check everything else. But if everything else looks good, you may need to go back and clean the carb again.

Kadbow · Feb 28, 2018

Jeremy or Carolina do you guys have the original carburetor? Mine has a Zenith carb, don’t have a clue what model or the settings for the idle air and main jet. Anybody know. Also not knowing the model carb I don’t know what rebuild kit to get. Any help appreciated.

Kadbow · Feb 28, 2018

RM-MN, my spark looks a little week but the points are new. Could it be the old plug wires. I did discover the previous owner had the coil wired backwards but it didn’t seem to make any difference when I switched it.

Carolina boy · Mar 1, 2018

Mine has the original Marvel carb. I am sure there is a better way to set the mixture and air flow settings, but I just started tweaking both until it
ran smooth at all RPMs. Probably the octane in the gas has something to do with all of this. At any rate it is not the same stuff that was burned in
it during the 1950's. I can echo Jeremy, sometimes in cleaning the carb, the 3rd time is the charm. Good luck.

Steve@Advance · Mar 1, 2018

A couple other things to check:

Be sure the gas tank is vented. Try running with the cap off just for a test.

Not sure about that carb, but some the venturi can be installed upside down, that will cause lean running, hold the bowl away from the top so no idle.

To adjust the main, with the engine at idle and warmed up, the engine should take sudden full throttle without hesitating. Keep opening the main until it responds quickly, a single puff of black smoke is desirable.

Back to the ignition, be sure the distributor shaft doesn't have side play, and the centrifugal advance is free. Try the old condenser, new ones are known for being bad out of the box.

Ron(Ont) · Mar 1, 2018

(quoted from post at 06:01:22 03/01/18) A couple other things to check:

To adjust the main, with the engine at idle and warmed up, the engine should take sudden full throttle without hesitating. Keep opening the main until it responds quickly, a single puff of black smoke is desirable..

For the Zenith carb., initial adjustments are Idle Screw one turn open. CCW will further lean the mixture. The Main Jet requires two turns open and CCW wil richen the mixture.

Kadbow · Mar 1, 2018

Thanks for all the help guys. I got frustrated with the carb work and went to work on the electrical side. Replaced the condenser and it runs with no choke. Woohoo! I will give it a better test this weekend under a little load. Thanks again.

TO 30 Will not run unless choke is pulled

Kadbow

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