tractor wont start when hot

[bowman316]

I have a 1951 farmall cub tractor, and it wont start when its hot. if you never turn it off, it will usually not stall out. but god help you if you stall it out when its hot. sometimes its easier to start than other times. maybe humidy plays a factor. sound like the magnetio? I also have a 40 hp evinrude that does the same thing, funs fine till it gets hot, then nothing.

 

[midcarolina]

When you say it won't start when hot do you mean the starter engages and spins the motor or the starter will not turn the motor?

Probably need some more info on both.......... but I would post the evinrude in it's proper forum to get the most hits...........

By the way when I had a couple compact tractors a few years ago I got some great info at tractorbynet.com

 

[bigdee]

Hard to start when hot is usually a fuel problem. Vapor lock is one possibility, this can be exasperated if you use "winter"gas. A tired engine with weak compression is another possible cause.

 

[2kvert]

I'd guess vapor lock or if they have a ballast resistor like older Chrysler products that will do that as well

 

[bigdee]

No,Farmall used a magneto up until 1953.

 

[bowman316]

No, it will turn over when its hot, it just wont start. how do you check to see if its charging the battery? It has a magneto, that needs part of it filled with oil. it was bone dry in there

 

[bigdee]

No, it will turn over when its hot, it just wont start. how do you check to see if its charging the battery? It has a magneto, that needs part of it filled with oil. it was bone dry in there

It has a generator to charge battery. Check voltage on battery while running,should be >than 6 volts with engine running above idle. 7 to 7.5 volts is ideal. Your tractor does not require a battery to keep it running. Battery is only for lights and starter. You can crank that tractor with the hand crank without a battery!

 

[bowman316]

Oh, I have gotten many blisters hand cranking that thing, after killing the battery. It gets plenty of spark, now I think its a cooling issue. I just idled it for 5 mins, after filling it with coolant. right away coolant stared pouring out the overflow drain. and the coolant cap go really hot. its like the coolant is not circulating.

 

[bowman316]

The tractor ran fine today. I even shut it off hot, and started it back up! I think it runs fine in low humidity, but bad in high humidity

 

[MTboatguy]

Check your filters, I have had difficulty in high humidity on many smaller engines, especially older ones, those old fuel tanks draw moisture, also make sure that rust has not accumulated in the tank, I used to have an old Ford truck, that ran great for 15 miles, then quit, had to wait 45 minutes then it would start up and run fine for a while, finally found out that there was rust in the bottom of the tank and it was picking rust up, plug the filter, when it cooled off, the fuel would draw back into the fuel line and flush the rust out of the filter.

 

[rbh]

I would look at bad wires or cap on the magneto (Possibly bad plugs?)

Fire the tractor up when its dark and get a spray bottle, put it on fine mist and mist all the plug wires, mag ETC and look for blue sparks jumping to ground.

 

[bowman316]

This does have some questionable 1950s wiring on it. I mean most has been replaced. But some of the wires are like wraped in a white fabric. They used crazy looking wires back then

 

[dingbat]

This does have some questionable 1950s wiring on it. I mean most has been replaced. But some of the wires are like wraped in a white fabric. They used crazy looking wires back then

That crazy white fabric is most likely asbestos. Commonly use as heat resistant cable looms

Oh ya, engine problem...typical symptoms of a ignition condenser on the way out. Change the points, condenser and rotor cap. Problem solved.