Farmall M Intake Preheater: Carb Icing

[Dakota Farmall]

I am having tons of carb icing issues on my 1950 Farmall M. I cleaned the carb since the tractor had mostly sat for several years. It has been an exceptionally wet and warm Fall/Winter so far this year. Temps have been generally between +20F to +45F. I understand that this is the perfect scenario for carb icing. It thaws out fairly quickly after the internal icing kills the engine and will start right up again after a few minutes.

I am wondering if I am running it too rich? I turned the main screw on the carb three turns open.

I built a hodgepodge intake preheater (ie a 10" tin can with an 8" piece of flashing riveted to the can and sealed with duct tape) and that did not seem to help. The tin can and flashing extension are open at the bottom. I have a hole cut in the side and a piece of tubing going straight into the intake. Should I enclose the bottom of the "can" surrounding the muffler? I am not sure there would be enough air flow to the engine through the tin can with the bottom more sealed up than open?

If anyone has pictures of their air intake preheater setups, that function well, I would love to see them!

I will try to get a picture of mine posted here. It is fairly crude and made with stuff I had laying around.

Thanks!

Also, to save some well intentioned person the time of a post explaining carb icing, I am familiar...I learned all about carb icing +20 years ago flying little single engine airplanes.

 

[rustred]

I am having tons of carb icing issues on my 1950 Farmall M. I cleaned the carb since the tractor had mostly sat for several years. It has been an exceptionally wet and warm Fall/Winter so far this year. Temps have been generally between +20F to +45F. I understand that this is the perfect scenario for carb icing. It thaws out fairly quickly after the internal icing kills the engine and will start right up again after a few minutes.

I am wondering if I am running it too rich? I turned the main screw on the carb three turns open.

I built a hodgepodge intake preheater (ie a 10" tin can with an 8" piece of flashing riveted to the can and sealed with duct tape) and that did not seem to help. The tin can and flashing extension are open at the bottom. I have a hole cut in the side and a piece of tubing going straight into the intake. Should I enclose the bottom of the "can" surrounding the muffler? I am not sure there would be enough air flow to the engine through the tin can with the bottom more sealed up than open?

If anyone has pictures of their air intake preheater setups, that function well, I would love to see them!

I will try to get a picture of mine posted here. It is fairly crude and made with stuff I had laying around.

Thanks!

Also, to save some well intentioned person the time of a post explaining carb icing, I am familiar...I learned all about carb icing +20 years ago flying little single engine airplanes.

all i can say it to let the engine warm up at 1/2 throttle for about 15 minutes before using it. i have all kinds of experience with these tractors and there is piles of them running in cold temperatures with the carb being white from frost due to the ventury effect , but i have not had any stall due to that. and 3 turns out on the main needle is quite sufficient at 5 turns out the needle is out of the jet so thats as far as person needs to have it out on a heavy pull. myself instead of building a prewarmer i would enclose the whole side of the engine just like the old heat houser's did. at them temperatures thats not very cold anyhow comparing to to minus 10 -25 f. when i used to run them. see how the spark plugs are burning also. maybe need a hotter plug. not a whole lot a person can do other than just let it warm up on its own.

 

[Janicholson]

I would roughly enclose the heater you have made. There is very nice spiral flex tubing to make a good connection to the heater.

 

[Janicholson]

hoseOne source of hose

 

[Dakota Farmall]

all i can say it to let the engine warm up at 1/2 throttle for about 15 minutes before using it. i have all kinds of experience with these tractors and there is piles of them running in cold temperatures with the carb being white from frost due to the ventury effect , but i have not had any stall due to that. and 3 turns out on the main needle is quite sufficient at 5 turns out the needle is out of the jet so thats as far as person needs to have it out on a heavy pull. myself instead of building a prewarmer i would enclose the whole side of the engine just like the old heat houser's did. at them temperatures thats not very cold anyhow comparing to to minus 10 -25 f. when i used to run them. see how the spark plugs are burning also. maybe need a hotter plug. not a whole lot a person can do other than just let it warm up on its own.

I have a guy near me who can make an enclosure. I was just hoping this would be a cheaper setup that would eliminate that need.

The last time this happened, I let it warm to 140F on the temp gauge before I used it. I was out in the open in 45 mph winds which likely didn't help.

We must be in the same neck of the woods in terms of winter temps. The issue right now is the warmer than normal temps. If it would drop to subzero like normal, this would be much less of a factor. This was the 2nd warmest December on record for us! Not complaining as I hate doing chores at -35F actual temps and usually combined with some other ungodly windchill factor on top of that...

Thanks!!!

 

[used red MN]

I have a guy near me who can make an enclosure. I was just hoping this would be a cheaper setup that would eliminate that need.

The last time this happened, I let it warm to 140F on the temp gauge before I used it. I was out in the open in 45 mph winds which likely didn't help.

We must be in the same neck of the woods in terms of winter temps. The issue right now is the warmer than normal temps. If it would drop to subzero like normal, this would be much less of a factor. This was the 2nd warmest December on record for us! Not complaining as I hate doing chores at -35F actual temps and usually combined with some other ungodly windchill factor on top of that...

Thanks!!!

Back in the day on the farm when we ran our Farmalls in the cold, paper feed sacks would get wired to the grill and one wired along side the carb hopefully staying away from the exhaust manifold far enough so it did not catch on fire. We had plenty of bale wire because we used a wire tie baler. All that is LOL!
Not sure if you really need this but to be effective you will either have to draw air into the intake stack from an enclosure around the muffler. Or you will need to have your enclosure use the fan to force air over the exhuast manifold. Then blow it down towards the carb over the upward intake runner above the carburetor. If you are just trying to make an enclosure over then manifold and outer part of the carb you will probably not receive the results expected. The heated air behind the enclosure will just convect up and no heat will get to the needed area. Show us a picture of what you attempted to make. The picture icon at the top to the right of 2 chain links will let you choose the picture file from your folder to post it.

 

[Dakota Farmall]

Back in the day on the farm when we ran our Farmalls in the cold, paper feed sacks would get wired to the grill and one wired along side the carb hopefully staying away from the exhaust manifold far enough so it did not catch on fire. We had plenty of bale wire because we used a wire tie baler. All that is LOL!
Not sure if you really need this but to be effective you will either have to draw air into the intake stack from an enclosure around the muffler. Or you will need to have your enclosure use the fan to force air over the exhuast manifold. Then blow it down towards the carb over the upward intake runner above the carburetor. If you are just trying to make an enclosure over then manifold and outer part of the carb you will probably not receive the results expected. The heated air behind the enclosure will just convect up and no heat will get to the needed area. Show us a picture of what you attempted to make. The picture icon at the top to the right of 2 chain links will let you choose the picture file from your folder to post it.

I will post a picture when I have one. I haven't taken any pictures of my Farmall M shenanigans yet...

 

[Mark EC.IN]

I have a 560 that has a lot of icing problems.

If I put a couple of cans of the HEET gas treatment in the tank it will keeps the tractor running. The carb still ices on the outside, but the fuel flows and the tractor continues running correctly.

 

[wore out]

I am having tons of carb icing issues on my 1950 Farmall M. I cleaned the carb since the tractor had mostly sat for several years. It has been an exceptionally wet and warm Fall/Winter so far this year. Temps have been generally between +20F to +45F. I understand that this is the perfect scenario for carb icing. It thaws out fairly quickly after the internal icing kills the engine and will start right up again after a few minutes.

I am wondering if I am running it too rich? I turned the main screw on the carb three turns open.

I built a hodgepodge intake preheater (ie a 10" tin can with an 8" piece of flashing riveted to the can and sealed with duct tape) and that did not seem to help. The tin can and flashing extension are open at the bottom. I have a hole cut in the side and a piece of tubing going straight into the intake. Should I enclose the bottom of the "can" surrounding the muffler? I am not sure there would be enough air flow to the engine through the tin can with the bottom more sealed up than open?

If anyone has pictures of their air intake preheater setups, that function well, I would love to see them!

I will try to get a picture of mine posted here. It is fairly crude and made with stuff I had laying around.

Thanks!

Also, to save some well intentioned person the time of a post explaining carb icing, I am familiar...I learned all about carb icing +20 years ago flying little single engine airplanes.

IMHE, burning E-10 helps, at least SOME with the INTERNAL carb icing that can stall an engine.

Photo of the carb on ''Ingrid'', my 4020 snowblowing tractor. She was contentedly running despite the bad external icing because of manifold preheat and E-10.

Have you had your tractor iced up to this degree?

 

[Dakota Farmall]

I have a 560 that has a lot of icing problems.

If I put a couple of cans of the HEET gas treatment in the tank it will keeps the tractor running. The carb still ices on the outside, but the fuel flows and the tractor continues running correctly.

The old timer neighbor mentioned that could be an option. You confirmed he wasn't crazy.

 

[Dakota Farmall]

IMHE, burning E-10 helps, at least SOME with the INTERNAL carb icing that can stall an engine.

View attachment 1159

Photo of the carb on ''Ingrid'', my 4020 snowblowing tractor. She was contentedly running despite the bad external icing because of manifold preheat and E-10.

Have you had your tractor iced up to this degree?

Nah man, mine just gets frosty on the outside and dies if I run the throttle over 3/4 open. That is a heck of a lot of ice building up.

 

[BarnyardEngineering]

Nah man, mine just gets frosty on the outside and dies if I run the throttle over 3/4 open. That is a heck of a lot of ice building up.

I don't think that's all carb icing. Looks more like the tractor sat out in the freezing rain.

For some reason some carbs ice up but most don't seem to. The difference has to be in the tuning but there is only so much you can tune on these carburetors. I wonder if it's manufacturing variations in the venturi since the venturi is what causes the carb icing in the first place.

If it were such a widespread problem you'd think there would be gadgets out there to address it. "M&W Carb De-icer" or something like that.

I've seen lots of "solutions" ranging from scraps of steel roofing wired on, to old feed backs, to tarps, to plywood... anything to contain some heat around the carburetor. A heat houser would probably be the most "civilized" solution.

 

[Dakota Farmall]

Here are some pictures of my current spare parts used:

 

[Janicholson]

I would pull that down near the bottom of the muffler, then make a couple of interlocking pie plate covers for the bottom, forcing the air to come in from the top. loose fits are fine. A wrap of fiberglass around it would not hurt either. Jim

 

[rustred]

that setup is not doing much. better off without that. and i think that is causing more icing than just the original set up. i would cap that top pipe and put a tee in that upright the same size under the hood to suck warm air off the manifold . lots more heat there. then in the summer cap the tee and put your precleaner back on. plus get some 1/4 inch plywood and make it fit nice under the hood up to the grill resting on the frame and have it anchored with a couple screws or small bolts. need to keep that side of the engine warm from the fan sucking the air from the warm rad which should also be covered in the front and experiment with how mush to open the top on warmer days. keep the bottom closed up to 3/4 of the way to the top. there is no getting around carb icing as thats the fact of the matter . you can feel above the carb in july and it will be cool. in winter it is just a colder situation. my idea which is what i would do if i would actually have this give me a problem.

 

[Dakota Farmall]

I would pull that down near the bottom of the muffler, then make a couple of interlocking pie plate covers for the bottom, forcing the air to come in from the top. loose fits are fine. A wrap of fiberglass around it would not hurt either. Jim

Yeah, extending the bottom tube and closing the bottom should help. I might get crafty with the exhaust tape I have have had sitting around for 10+ years.

That intake combined with side covers to retain heat should help this situation.

 

[Dakota Farmall]

that setup is not doing much. better off without that. and i think that is causing more icing than just the original set up. i would cap that top pipe and put a tee in that upright the same size under the hood to suck warm air off the manifold . lots more heat there. then in the summer cap the tee and put your precleaner back on. plus get some 1/4 inch plywood and make it fit nice under the hood up to the grill resting on the frame and have it anchored with a couple screws or small bolts. need to keep that side of the engine warm from the fan sucking the air from the warm rad which should also be covered in the front and experiment with how mush to open the top on warmer days. keep the bottom closed up to 3/4 of the way to the top. there is no getting around carb icing as thats the fact of the matter . you can feel above the carb in july and it will be cool. in winter it is just a colder situation. my idea which is what i would do if i would actually have this give me a problem.

I am merely trying to warm the air to get myself out of the carb ice temp/dew points in the curve below. If the air is warmed it drops the relative humidity due to no moisture being added to the system.

I might work on this to see what it does with temps being in the single digits next week. You can get around the impacts of carb icing, which they have done in piston engine aircraft for decades. I am just trying to find the heat and pipe it to the most use like the aircraft manufacturers do.

Covering the front/radiator should really help keep the heat as well!!

I also liked the idea of adding some Heet to the fuel as well.

The combination of efforts should reduce the impacts enough to get a functional winter machine.

 

[charlieu]

I made a hot air intake for my SMTA years ago and It's amazing how nice it runs in the winter. Here a couple pictures

 

[Dakota Farmall]

I made a hot air intake for my SMTA years ago and It's amazing how nice it runs in the winter. Here a couple pictures

So your bottom end is open? I may need to make some changes to my setup and make it a little more refined. I might try to find some actual metal exhaust pipe to incorporate into this and not plastic tubing...lol

 

[charlieu]

I used a piece of 8 inch stove pipe, an 8 inch round cake pan for the top and the piece of exhaust pipe that I had the muffler shop in town bend to a 90 degree angle. Everything just slips together and does not have to be air tight. I got this idea from the old IH pickup from the early 70's with their hot air intakes.