Ford 850 Rough Under Load

[spkepler]

I have a 1956 Ford 850. It starts like a champ and runs well for the most part. I use with a finish mower for cutting my lawn. After mowing for about a hour, the tractor will suddenly start running very rough. If I push in the clutch, it runs a bit smoother. Then after 20 seconds or so, starts to run well again. I can continue mowing, but the problem randomly reappears. If I shut down the tractor when it is running rough and wait 5 minutes, it starts right up and runs well ... for a while until the problem starts a gain.

It has new gas and a 12 v electronic ignition.

 

[old]

A little dirt in the carb will cause such problems and some times if you choke it a couple times when it starts doing that it will suck the dirt out and run good for a while.

 

[Ken-Pa]

Definitely dirt is stirred around after some time of use . Try dropping the drain plug of carb & catching the gas in a clean jar for a few seconds , then reinstall the plug . If you don't get a steady stream of gas by then , you may wanta retry this method until you do . You may also have a dirty tank . HTH ! God bless, Ken

 

[NoNewParts]

dirt or water in the gas
put a petcock on the bowl drain, so you can check
flow immediately when it starts to stumble.
(and get the water out)
check too for a plugged gas cap/tank vent

also, 800 series tractors have an issue with the gas line
being too close to the exhaust manifold.
under hard work, the gas in the line can get hot enough
to boil.
boiling gas goes up, blocking flow down.
all 800's I've had took some gas line re-engineering
or insulation.

 

[6t6cuda]

that sounds like what mine did...

Do check the gas, but that did not do anything for me.

What fixed it for me was converting to a pertronix ign. I bought a new condenser and points, but from what I understand they are crap anymore and the good ones are like $25, rather than buy expensive points I just went electronic and it cleared right up for me...

This was after a complete rebuild (carb, engine, etc..)

 

[souNdguy]

you mention ei and 12v.. for the heck of it.. check spark.

now.. after that.. check fuel flow.. look for excess water or sediment.

at moment of stall recheck spark and fuel thru carb bowl drain.

I suspect fuel issues in this set of circumstances.

soundguy

 

[souNdguy]

he mentioned he already has ei...

 

[cheif]

Had a similar problem on mine. After trying all the logical tactics the problem turned out to be a crack in the intake manifold.