TO-35 Air Flow (Choke) Ideas to Keep Running?

[Farmer Shawn]

Hi! New to the forum and a new owner of a 1955 Ferguson TO-35. Front loader and backhoe configuration. Tractor uses a 12V battery but the coil is 6v and I've gone through the electrical system top to bottom and everything checks out great.

Also just went through a minor tune up to get the tractor running and am having an issue. Cleaned the fuel lines, strainer, fuel bowl and the air filter bowl and replaced with fresh oil.

The tractor turns over fine and will start. However, I have to cover the air inlet with my hand to choke the air flow down to keep it running. The tractor choke, though attached and unrestricted in movement, has no apparent effect. I'm about to pull the Marvel-Schebler carb and rebuild it. I'm thinking the choke butterfly is not moving at all based on the engine response, even though the actuator on the carb moves.

To keep the tractor running at low or high idle, I estimate that I am restricting probably 85-90% of the airflow to the intake. If I remove my hand the tractor dies. It just seems like a mighty large restriction in air flow to keep it running and I'm wondering if this is normal or not? I would think that once its warmed up I should be able to open the choke all the way and the engine will leverage full air flow. I can keep the engine running for up to 15-20 minutes using this method, but it's not practical for actual operation.

Any suggestions out there beyond the carb rebuild?

 

[Inno]

Nope, not normal. It's not getting enough fuel.
Definitely do a carb rebuild and make sure you clean out ALL the tiny passages very well. Also make sure you have good flow of fuel from the tank to the carb. There is a screen in the float bowl that you can take out and clean as well as a screen on the float bowl inside the tank, you'd have to drain the tank and unthread the float bowl to get at that one. You can remove the fuel line from the carb and open up the valve to check the fuel flow before going that far. It should be a steady stream, not just a trickle.
If you are using a 12V battery, switch to a 12V coil. You will quickly burn up that coil, that could also be causing some problems. When upgrading from 6 to 12V EVERYTHING must be 12V.

 

[Farmer Shawn]

Thanks Inno!

I did clean the fuel screen in the glass separator bowl, but didn't hit the one in the tank. I'll rebuild the carb and confirm fuel flow. Thanks!

 

[oldmisterbill]

When you do the carb rebuild - don't forget to find and clean the small passage that runs to the idle mixture valve,or it won't idle smooth.

 

[2tractors]

If you screw the small air adj. all the way in and it stills runs then you have an air leak either on the carb. or on the intake but it's like Inno said, starving for fuel.Take off the drain screw on bottom of carb, drain bowl and then turn on the gas.

 

[Z-man]

I agree it sounds like it may have something in the carb probably dirt that is blocking the fuel from getting were it needs to go. u may even be able to just clean the carb as is a it will run but there is nothing like new parts to use

 

[Farmer Shawn]

Thanks for the ideas and things to look out for. I have a carb kit on the way and will clean everything this weekend, make the suggested adjustments and see where we land!

 

[Inno]

It might be a good idea, while you are waiting for the carb kit, to take it all apart and get it soaking in some carb cleaner or simlar. I have heard that toilet bowl cleaner does a really good job and it's not too expensive compared to a carb dunk, I haven't tried it myself but I plan to on my next rebuild.

 

[Jason S.]

(quoted from post at 16:37:53 10/23/13) It might be a good idea, while you are waiting for the carb kit, to take it all apart and get it soaking in some carb cleaner or simlar. I have heard that toilet bowl cleaner does a really good job and it's not too expensive compared to a carb dunk, I haven't tried it myself but I plan to on my next rebuild.

I've used toilet bowl cleaner for several years now on cleaning old cast iron carbs. Just make sure there is no aluminum because it will cause a bad chemical reaction and cook the aluminum, but it works really good on cast iron,brass,bronze,steel,etc...

Before hand

After 15 mins in toilet bowl cleaner

 

[Bob (Aust)]

Aside from partial fuel starvation, you may have an air leak? Could be between the carby and manifold or manifold and head? Spray a little Aero Start around possible leaks and see if the engine picks up.

Get rid of that 6 volt coil and install the correct 12 volt coil.

 

[Farmer Shawn]

Jason- Wow that did a great job of cleaning up the carb!