need help! ford 601 gas

[TommyB1974]

Father-in-law called and said his ford 601 was barely running and leaking fuel out of the carburetor. I brought it to my shop and it was running very rich when i got it started and fuel running out of the intake of the carburetor. I had a hard time making out the tag on the Marvel Schebler carburetor and ordered the wrong kit the first time, but I figured it would still work. After reassembly there was no change. I finally figured out it is a TSX-765 and I ordered the correct kit and a new float. after assembly I still got fuel leaking out of the carburetor intake. Both adjustment screws were tuned out 1 turn, and the float was set to 1/4" (measured with the gasket on). I added an 1/8 of an inch to the float level and fuel has stopped running out of the carb, and I got the tractor started. However, it's still running very rich and as soon as I try to throttle up, it spits, sputters and dies. Petcock and sediment bowl and fuel line have been replaced but are the factory design.
This is not the first Marvel Schebler I have rebuilt, and I have had this thing apart 10 times today double checking everything I can think of. any help would be appreciated.

 

[DPittman]

Possible air restriction some where. If you test start it with the air filter off we can eliminate that possibility. The only time I ever had a running rich problem has always been the float or the load jet which both were corrected with adjustment.
Head scratcher for me

 

[TerryfromSWIowa]

Have you checked for a plugged air intake?

 

[TommyB1974]

Air filter is off. I also replaced the manifold as the old one was cracked. I have all the tin off because I replaced the petcock in the tank as well.

 

[john in la]

When you put the float needle seat in did you check to make sure the gasket was sealing.
Hold finger over needle hole and blow/suck on the fuel line hole.
Sometimes the threads/gasket will not seal and fuel will leak into the bowl even though the needle is cutting off fuel flow through the seat hole.
If it is leaking take the seat out and apply a small amount of permatex anaerobic gasket maker to the threads and reinstall it.

Once you do this install the needle float and spring. Adjust the float to where it is level on all 4 corners and try the blow/suck again to make sure the needle and seat are sealing.

I assume since you have rebuilt carbs in the past you replaced the idle run adjustment seats and installed the throttle butterfly in the exact same orientation it was when you took it apart to clean it.

 

[Curt Cooke]

Long shot. Be sure the gasket between the top and bottom half of the carb is correct for the application and that the bowl vent holes in the carb halves are not blocked by the gasket. If the bowl can't vent, it won't fill and stop. It will either not allow fuel in OR a siphon will occur and it will leak continuously.
CC

 

[G Smith]

Long shot. Be sure the gasket between the top and bottom half of the carb is correct for the application and that the bowl vent holes in the carb halves are not blocked by the gasket. If the bowl can't vent, it won't fill and stop. It will either not allow fuel in OR a siphon will occur and it will leak continuously.
CC

I had that happen,

 

[TommyB1974]

Thank you guys. Everything was replaced in the carb and I’m getting the same results as I had before. I will verify that the seat threads are sealing. I did take the bowl off the carb and the flow stopped when I very lightly pushed up on the float. I will verify that that is the correct gasket

 

[showcrop]

Thank you guys. Everything was replaced in the carb and I’m getting the same results as I had before. I will verify that the seat threads are sealing. I did take the bowl off the carb and the flow stopped when I very lightly pushed up on the float. I will verify that that is the correct gasket

I saw somewhere that the little gasket under the float valve seat tends to be problematic, so I put a tiny bit of a sealer on mine.

 

[Maineman]

Air filter is off. I also replaced the manifold as the old one was cracked. I have all the tin off because I replaced the petcock in the tank as well.

I would double check for a manifold leak.
Hand over carb intake. Do you feel suction?
Pull spark plugs thumb over hole do you feel suction?
Maybe a compression check is in order.
That's what I'd check.

Joe

 

[TommyB1974]

Here's where we are at. I took the carb apart again. Soaked it in acid, spent 2 hours with pipe cleaners, carb cleaner and compressed air. I had fiddled with the timing so i adjusted it back to 8 degrees btdc. started it, reved it up, played with the idle screw a bit and it seem to be running great. drove it around in my pasture for about 5 min in high range and its got plenty of power, and then..... it started cutting out if you come up off idle. I got it back to the shop and it sounds great at idle and had power to pull the tractor into the shop but as soon as i give it gas it starts spitting and sputtering like it can't catch itself.
I did notice the rotor is loose and can pivot a bit in the distributer. I'm not sure if that could be my problem or not.

 

[Jim.ME]

If the rotor is loose, is the spring clip (#38 in the drawing) on the shaft under the rotor? It keeps the rotor from moving around on the shaft.

 

[TommyB1974]

That helps, that part is not there!!

 

[TommyB1974]

neither are 36/37 washers! Thank you!

 

[Jim.ME]

neither are 36/37 washers! Thank you!

36/37 are general secured in the dust cap, not loose. Check your dust cap carefully, I expect they are there.

 

[mjsnodgrass]

Father-in-law called and said his ford 601 was barely running and leaking fuel out of the carburetor. I brought it to my shop and it was running very rich when i got it started and fuel running out of the intake of the carburetor. I had a hard time making out the tag on the Marvel Schebler carburetor and ordered the wrong kit the first time, but I figured it would still work. After reassembly there was no change. I finally figured out it is a TSX-765 and I ordered the correct kit and a new float. after assembly I still got fuel leaking out of the carburetor intake. Both adjustment screws were tuned out 1 turn, and the float was set to 1/4" (measured with the gasket on). I added an 1/8 of an inch to the float level and fuel has stopped running out of the carb, and I got the tractor started. However, it's still running very rich and as soon as I try to throttle up, it spits, sputters and dies. Petcock and sediment bowl and fuel line have been replaced but are the factory design.
This is not the first Marvel Schebler I have rebuilt, and I have had this thing apart 10 times today double checking everything I can think of. any help would be appreciated.

i had the same issue once. discovered somehow the float got tweaked a little, and when carb was assembled one float was rubbing on the inside of carb. i saw the marks on the float thankfully or i'd still be messing with it. good luck

 

[used red MN]

neither are 36/37 washers! Thank you!

I would guess Jim doesn’t mind if I divulge his sources. That is from the manufacturer’s online parts catalog for your tractor, here is a link. CNHI Ford 601 parts catalog Even if that seal and retainer are not there it will have no effect on whether your engine runs properly or not. It is just a “good thing” designed into a distributor that may operate in dirty conditions. The majority of all road vehicles with points ignitions were not equipped with points dust covers. It would be good for you book mark (Favorite) that link. That link will let you view all the parts diagrams for that tractor if you view it on a PC it will be evident on a phone clicking “Table of Contents” will open the main index of the “Functional Groups” I guess it isn’t your tractor, but probably a good reference if you’re working on it.
I have some info for you on your carb. May not reveal the problem but rather it is some things that you probably don’t realize are going on in that updraft tractor carb. I will have to see if I can find a link to a previous post on here so I don’t have to retype it all. Hopefully I’ll be back a bit later with that.

 

[used red MN]

I have some info for you on your carb.

Hopefully I’ll be back a bit later with that.

Here goes,
I always wondered how most tractor carbs got away without an accelerator pump and avoided the “tip in” bog associated with an automobile carb when the accelerator pump quit working. It wasn’t until late last year that it came to light in a Marvel-Schebler tractor carb manual. Tractor carbs have an “acceleration well” that takes the place of the accelerator pump. (continuing my newly acquired knowledge is in part from the manual I am linking)
I am going to link that manual and the main just of what I am going to say can be referenced in it mainly on page 7 in the Power Fuel Feed System section.
Most simple updraft tractor carburetors have a 2 inch or so long main power nozzle tube. One end sticks out into the air stream passing through the venturi area of the carb air way. The other end of the nozzle tube is cross drilled with a series of holes and the end opposite of the venturi end is open. Fuel feeding from the bottom of the carb bowl through a jet whether fixed or adjustable flows into and around the lower portion of the nozzle, whether by gravity of the level of gas in the bowl or by the pressure drop in the venturi. The fuel floods into the passage or cavity that the tube passes through. Part of this space is the “acceleration well” refer to 16 on the diagram in the manual. This small reserve of fuel is there ready to be taken up to the air stream when the throttle plate is opened to drop the pressure in the venturi. Once that “reserve” of fuel is used up only what can meter through the main jet is available to provide a constant mixture as needed. Now secondly there is something else that is very important going on in that nozzle tube. The series of cross drilled air bleeds (#15) are also utilized at this point. Due to the low pressure in the venturi the fuel flows out fast enough that it wants to be displaced and the displacement element is air coming through the nozzle air vent #21. It was about a year or so ago when someone posted a cut-away of a carb to show the choke system that I figured out on my own the purpose of the series of air bleeds on the tube. They mix air with the gas giving an “emulsified” mix to move up tube to dump into the air stream. If this system isn’t functioning right the engine will run and respond poorly. Making sure that air can get in there for this function is very important and rarely discussed when there is a problem with a carb running/operating poorly. This is mainly because people don’t understand it or know that it is happening. Prior to this revelation I thought there was only fuel/gas traveling through that tube. I am sure with this realization if I went back and reread the Rochester carb book I would find this same operation is going on in the circuits of those carbs. (The automotive carb book was referenced in the original writing this was copied from which was a private message to a member)
M/S updraft carb manual
Another item I came across had to do with habitual flooders. A carb builder on here posted about. The needle seats that screw in the carb are mass produced by the thousands and as most old tractor parts this takes place overseas. So the actual quality control of the precise finish that the float needle seat seals against is lacking. His fix is to “coin” the seat. He sells an actual tool for this but setting a 3/16” steel ball in the seat and giving it a good smack with a drift punch and a 16oz hammer does the same thing. Make sure after the love tap that you check the seat is still tighten snuggly.
Hope this helps.

 

[TommyB1974]

Tractor is fixed! Thank you all. Here is what the problem was. I found 1 hole in the bowl gasket that was a little off. I used a paper punch to correct it and the carburetor stopped leaking. However, it was still running rich, black smoke and it acted like it couldn't catch up with itself. The rotor was loose and it was missing a clip that when replaced, tightened everything up, but no improvement in how it was running. I ended up shutting then lights off in the shop and turned the motor over with the distributer cap off. There was a ton of arching at the points. I cleaned the points, replaced the condenser with one I had in my toolbox, and walla, its running like a top. Thank you all for your help! This just did not seem like an ignition problem, but it was.

 

[used red MN]

I ended up shutting then lights off in the shop and turned the motor over with the distributer cap off. There was a ton of arching at the points.

Interesting diagnosis method, never heard of watching the points in the dark. Sounds like you picked on the right problem, glad you got it running good.