Engine quits

Mon Jun 27, 2005 5:36 am

I have a farmall bn with a c113 engine and a zenith carb.
The tractor ran with no maintainance for about 5 yrs. then it over heated all the time so it set for about a year. Since aquiring it I had the radiator gone through ,flushed the coolant jackets changed the valve and pan gaskets ,adjusted valves ,cleaned as much oil sludge as I could with kerosene. Also had the carb rebuilt. I tell you this to ask the following
The tractor started right up but runs rough and quits after after about 5min. and will not start for about 10 min.
Not sure what the problem is can anyone help.
Thanks PWL

Mon Jun 27, 2005 6:20 am

Phil - it sounds like your coil may have gone south on you. What kind of spark are you getting? Is it a nice bright blue arc?

Mon Jun 27, 2005 6:28 am

seems to have good spark. would this quit after it runs for a while 5min or so?

Mon Jun 27, 2005 6:46 am

Only if the coil was really bad and heating up very quickly. Since you have gone through the carb, I thought I'd provide some alternate ideas. How is the fuel supply to the carb? Even though it was re-built, the carb can still be the issue. How about smoke? Do you see any kind of smoke when it is running? You also said you adjusted the valves. Did any of them appear to be sticky?

Mon Jun 27, 2005 6:53 am

no smoke my mechanic brother helped with the valves and seemed ok
When you say the coil heats up not sure what you mean? I thought i might be a fuel problem so I took the glass off cleaned it good made sure the gas cap was breathing etc. So it may be a mag issue. It would Figure, I have a mag issue on my cub as well.
What should I check? and how would I diagnose and solve this.

Mon Jun 27, 2005 7:12 am

Phil, if by some chance, it is a mag issue, the appearance of the spark will be the clue. Mags typically throw a nice bright blue spark for about 3/8 - 1/2" long when working properly. If the spark is weak and yellow looking there are problems.
Your symptoms really sound like fuel issues rather than spark but sometimes we get so intent and determined that one thing is the problem that we tend not to look at other possible contributing causes.
When I mentioned coil heat, coils that are beginning to fail tend to start generating heat as the dielectric materials in them start to break down and leakage current occurs. Generally, this shows up after running for a period of time that is anywhere from about 30 minutes and up. Hard starting when hot is another classic complaint.
I mentioned earlier that even though the carb has been rebuilt, there may still be issues. The float may be hanging or mis-adjusted or there may be dirt in the fuel tank working it's way to the carb and plugging the jets.
There are many possibilities, the fun part is sorting them out. Keep plugging away and we'll try to help if we can.

Mon Jun 27, 2005 7:49 am

As always thanks. I'll start with the fuel then work to the Mag.
I will let you and others know what the problem was, I'm sure I won't be the only one with this problem.

Mon Jun 27, 2005 8:48 am

Speaking of problems with the fuel I had a problem with my cub doing the same thing. It turned out that a bee had gotten into the gas tank and after awhile it got sucked into the intake. The cub would run for an indermint amount of time (sometimes 5 minutes sometimes longer) until the bee got suked into the intake again and it starved the motor. The way we found it was I had a friend watch the sediment bowl while I ran the cub and he noticed that the bowl would not get filled just before the cub died. By the time I had gotten off the cub the bowl was pretty much full again so that is why I never noticed it before. I kept thinking it was a carb problem :oops: .