Tractor won't run when it's under load

[Greg Baisch]

I have a problem that has exceeded my
troubleshooting capabilities. This is the history
of what i have done so far this year:

- New 12V kit installed including a new 12V coil.
- Rebuilt the carb.
- Sent the fuel tank in to get boiled to clean
out some old rust.
- Installed a new hard fuel line from the bowl to
the carb
- Flushed and cleaned the valve on the fuel tank.
- Cleaned all 3 of the fuel filters.

The tractor starts beautifully and runs great for
about 3 minutes. The problem starts when i put a
load on the motor and start working it. All i am
doing is pulling a harrow in our arena (4' wide
section with some weight) and when the tractor
warms up it starts bucking and eventually
(quickly) dies. After i let it sit for a few
minutes, it will start and run for another minute
and does the same thing.

I need some help on where to start looking next.
My first thought was that something was going
wrong with the governor, but after spending a few
hundred bucks chasing down a spark and fuel issue
i am not sure.

Thanks,

 

[souNdguy]

classic fuel starvation and leaning out.

the fac that it starts and runs fine for a few minutes, and restarts means your timing, compression, and spark are FINE.

only thing lefts IS fuel. the 'setting' is more fuel trickling back into carb bowl.

as she starts to die, i bet a bit of choke helps her.. that's a good test you can do.. or just jump in and test fuel flow thru bowl ( float valve )

soundguy

 

[Dell (WA)]

Greg........you complain......
The tractor starts beautifully and runs great for
about 3 minutes. The problem starts when i put a
load on the motor and start working it"........3-mins is usually a BAD condenser. Condensers can be BAD right outta the box.

2nd cause of 3-min runtime is fuel delivery. Wanna guess what happens when yer carb starts to run outta fuel???

3rd secret cause of weak sparkies is yer weaksister ignition switch. ($10, cheap) .......Dell, yer self-appointed sparkie-meister

 

[carolina don]

Remove your fuel cap and see if it will continue to run.If it runs with cap off.....probably gas tank vent clogged up.Drill a small hole in gas cap for vent. don b

 

[Greg Baisch]

Soundguy is right. When it starts to die i can throttle back the motor and apply a little choke and keep it running for a short time.

So i take it my carb is out of adjustment or needs another rebuild? Right now i have the mixture screw set at 1-1/2 turns and the other screw set at 1-1/4 turns. (i live at 2600 ft above sea level).

When will someone dream up a fuel injection system for these old tractors....ha ha.

 

[souNdguy]

make sure fuel flow to carb is good.. then make sure carb is clean.. especially elbow screen, inlet needle / float, and all jets. sometimes the float gets logged and heavy.. or hangs

bang on side of carb with wooden hammer handle or screwdriver handle when she goes lean and see if she goes ok.. also check for tank vacume.. though that usually takes a while to build..