MH 44 Won't keep running.

[Bar-Ranch]

I could use some help/ideas. I have a MH 44. It is a 44 GR, 4-cylinder, gas, S# 12653 with a Zenith carb and Continental engine. It starts fine and runs for about 5 minutes and dies. Minutes later it can be restarted, and runs for about 30 seconds and dies. There after it will start and maybe run for 10 seconds and die The choke can be pulled and pushed and it will sputter on for a few more seconds and then die. The carb was just rebuilt. The carb was just recleaned. The fuel line filter is brand new, the glass fuel filter bowel has been removed because the bowel screen was tore. The gas tank outlet is not clogged. The gas tank has been drained. It has new gas. Fuel flows freely and evenly through the fuel line to the carb. The carb inlet elbow is not clogged. The electrical coil has been replaced. Electronic distributor parts have been installed to replaced the points & condenser. The timing has been set and is good while running. The governor moves freely. The carb jet settings have been adjusted/altered with no change in the dyeing situation. Air suction at the air inlet of carb would take a glove off my hand. . I noticed ice crystals appear on the manifold, where it is connected to the top of the carb, and the crystals go up about 3 inches on the manifold. . Another note, when I recleaned the newly rebuilt carb, and was blowing out the carb orifices, it appears a "leg" of the new venturi, where it is pressed into the carb body was placed so it was somewhat blocking (not totally) a port/orifice that would feed into the venturi. Didn't look normal, but don't know. Any suggestions to try would be greatly appreciated.

 

[Stan Coryell]

I could use some help/ideas. I have a MH 44. It is a 44 GR, 4-cylinder, gas, S# 12653 with a Zenith carb and Continental engine. It starts fine and runs for about 5 minutes and dies. Minutes later it can be restarted, and runs for about 30 seconds and dies. There after it will start and maybe run for 10 seconds and die The choke can be pulled and pushed and it will sputter on for a few more seconds and then die. The carb was just rebuilt. The carb was just recleaned. The fuel line filter is brand new, the glass fuel filter bowel has been removed because the bowel screen was tore. The gas tank outlet is not clogged. The gas tank has been drained. It has new gas. Fuel flows freely and evenly through the fuel line to the carb. The carb inlet elbow is not clogged. The electrical coil has been replaced. Electronic distributor parts have been installed to replaced the points & condenser. The timing has been set and is good while running. The governor moves freely. The carb jet settings have been adjusted/altered with no change in the dyeing situation. Air suction at the air inlet of carb would take a glove off my hand. . I noticed ice crystals appear on the manifold, where it is connected to the top of the carb, and the crystals go up about 3 inches on the manifold. . Another note, when I recleaned the newly rebuilt carb, and was blowing out the carb orifices, it appears a "leg" of the new venturi, where it is pressed into the carb body was placed so it was somewhat blocking (not totally) a port/orifice that would feed into the venturi. Didn't look normal, but don't know. Any suggestions to try would be greatly appreciated.

You need fuel, air, and spark.

Spark is the easiest to rule out. It either has spark or it doesn't.

If I have something sputtering, I pull the air cleaner and get it running. When it starts to dye, spray some 2 + 2/ gum out in the carb. If that keeps it running, likely a fuel problem.

Stop changing parts and do some troubleshooting. The parts cannon usually adds to the problem. Wires get crossed, New condenser doesn't work, etc.

 

[Bar-Ranch]

Stan, thanks. I have the three you mention, (fuel, air & spark). Related to the parts, since the "ole girl" is 70 plus years old, those are the parts that have been checked, needed repair, or replacement not specific to trying to correct the dyeing problem. The distributor parts are relatively new (18 months) but I'll try changing them. I'll also call the company that rebuilt the carb and ask about the venturi location.

 

[Jim.ME]

Stan, thanks. I have the three you mention, (fuel, air & spark). Related to the parts, since the "ole girl" is 70 plus years old, those are the parts that have been checked, needed repair, or replacement not specific to trying to correct the dyeing problem. The distributor parts are relatively new (18 months) but I'll try changing them. I'll also call the company that rebuilt the carb and ask about the venturi location.

Have you held a jar under the carb bowl drain plug, removed the drain plug and check flow through the carb by timing how long it takes to get a pint in the jar?

 

[flying belgian]

I could use some help/ideas. I have a MH 44. It is a 44 GR, 4-cylinder, gas, S# 12653 with a Zenith carb and Continental engine. It starts fine and runs for about 5 minutes and dies. Minutes later it can be restarted, and runs for about 30 seconds and dies. There after it will start and maybe run for 10 seconds and die The choke can be pulled and pushed and it will sputter on for a few more seconds and then die. The carb was just rebuilt. The carb was just recleaned. The fuel line filter is brand new, the glass fuel filter bowel has been removed because the bowel screen was tore. The gas tank outlet is not clogged. The gas tank has been drained. It has new gas. Fuel flows freely and evenly through the fuel line to the carb. The carb inlet elbow is not clogged. The electrical coil has been replaced. Electronic distributor parts have been installed to replaced the points & condenser. The timing has been set and is good while running. The governor moves freely. The carb jet settings have been adjusted/altered with no change in the dyeing situation. Air suction at the air inlet of carb would take a glove off my hand. . I noticed ice crystals appear on the manifold, where it is connected to the top of the carb, and the crystals go up about 3 inches on the manifold. . Another note, when I recleaned the newly rebuilt carb, and was blowing out the carb orifices, it appears a "leg" of the new venturi, where it is pressed into the carb body was placed so it was somewhat blocking (not totally) a port/orifice that would feed into the venturi. Didn't look normal, but don't know. Any suggestions to try would be greatly appreciated.

Try taking the fuel tank cap off. I know that sounds to simple but thats what it was on my 49 chevy truck. The cap vent was plugged. Another thing I had happen was bug in the fuel tank of the 706 gas. When running it would suck down over tank outlet. Shut it off and it would float up and start again.

 

[Bar-Ranch]

Have you held a jar under the carb bowl drain plug, removed the drain plug and check flow through the carb by timing how long it takes to get a pint in the jar?

Hello JimME. I have not checked how long it takes to fill a pint jar, but the plug has been removed and there is a steady even flow coming out of the plug port. How long should it take to fil a pint jar? Thanks for your input.

 

[Jim.ME]

Hello JimME. I have not checked how long it takes to fill a pint jar, but the plug has been removed and there is a steady even flow coming out of the plug port. How long should it take to fil a pint jar? Thanks for your input.

no more than a couple minutes often

 

[Bar-Ranch]

Try taking the fuel tank cap off. I know that sounds to simple but thats what it was on my 49 chevy truck. The cap vent was plugged. Another thing I had happen was bug in the fuel tank of the 706 gas. When running it would suck down over tank outlet. Shut it off and it would float up and start again.

Hi Flying, OOH what a bother about the bug. That must have taken a while to figure out. i have the gas tank cap loose. I still have to check the vents on the cap to make sure they are not plugged. I am highly certain there is no bug, or any another darn thing plugging the fuel tank outlet. I used to have paint flakes plugging it, but got them cleaned out of the tank. Thanks for you thoughts.

 

[Bar-Ranch]

no more than a couple minutes often

I certain it will fill a pint in a few mintues.

 

[stevieb49829]

One other thing that snags some folks going through this same thing. Did you let the carb drain out, and the gas continued to pour out, or figured it was running gas out and all was well. It takes a bit of draining to get past the gas that is sitting in the carb bowl, to check the actual flow from the tank. It could also be an ignition issue, so next time it stops, pull the coil wire immediately and crank it over. If no spark, you probably have a component in that system that is failing when it warms up. But it really does sound like a stubborn fuel problem. Steve

 

[Bar-Ranch]

One other thing that snags some folks going through this same thing. Did you let the carb drain out, and the gas continued to pour out, or figured it was running gas out and all was well. It takes a bit of draining to get past the gas that is sitting in the carb bowl, to check the actual flow from the tank. It could also be an ignition issue, so next time it stops, pull the coil wire immediately and crank it over. If no spark, you probably have a component in that system that is failing when it warms up. But it really does sound like a stubborn fuel problem. Steve

Steve, thanks, I completely drained the gas tank through the fuel filter and fuel line to the point where the fuel line attaches to the carb. (about 2 gallons worth drained). Took the newly, professionally, (didn't do it myself) rebuilt carb (maybe 4-hours of use since rebuild) off and ran carb cleaner through every orifice and jet. Put 2-3 gallons of fresh gas in the tank. Removed the plug from the bowel of the carb and drained maybe a quart of gas out of the carb plug port. The coil is brand new. It was changed because the wire, and socket of the coil were corroded. 3-years ago a new electronic "ignitor" was put in place of the points and condenser.....maybe that's gone bad???

What I really has me thrown for a loop is; Why is there frost forming on the outside of the manifold, directly above where the carb is bolted to the manifold. The frost goes up the manifold from the carb/manifold gasket a couple of inches. Correction, I think I know the frost is forming from cold caused by the air flowing from the low pressure side of the venturi, which is hitting on the walls of the manifold. What I don't know is why? Has this got something to do with the governor? All I think I know is that the frost on the manifold is not normal, and, is never mentioned as a good thing in any manual I have ever read.

 

[stevieb49829]

Frost forms there when the gas droplets in the airstream actually turn to a gas, which draws heat to do so. If your air mass around the tractor is filled with cool moisture, it will condense on this cold spot on the manifold, and then freeze at lower temps. Same reason they put manifold heaters in airplane engines. If you pull too much of the heat out of the gas/air stream, the mixture becomes non-conducive to proper combustion. If this is when the tractor quits, I'd try a propane torch on the top of the carb and see if warm makes it run better. It's not an abnormal condition. Same thing happens on a propane tank when you lose a lot of propane quickly, like using a weed burner. The tank will frost up on the outside as the liquid turns to a gas inside the tank.

One of the things I've learned from being on this site is don't trust any electrical component, even right out of the box. If it is USA made you have a better chance of success than from some of the other countries. Your new coil could be a brand new rock!!. If you can scrounge up a good brand used coil, try changing it out as a test, even if you have to borrow it off your grandpa's old Chevy truck. steve

 

[Bar-Ranch]

Frost forms there when the gas droplets in the airstream actually turn to a gas, which draws heat to do so. If your air mass around the tractor is filled with cool moisture, it will condense on this cold spot on the manifold, and then freeze at lower temps. Same reason they put manifold heaters in airplane engines. If you pull too much of the heat out of the gas/air stream, the mixture becomes non-conducive to proper combustion. If this is when the tractor quits, I'd try a propane torch on the top of the carb and see if warm makes it run better. It's not an abnormal condition. Same thing happens on a propane tank when you lose a lot of propane quickly, like using a weed burner. The tank will frost up on the outside as the liquid turns to a gas inside the tank.

One of the things I've learned from being on this site is don't trust any electrical component, even right out of the box. If it is USA made you have a better chance of success than from some of the other countries. Your new coil could be a brand new rock!!. If you can scrounge up a good brand used coil, try changing it out as a test, even if you have to borrow it off your grandpa's old Chevy truck. steve

Stevieb; Thanks, for the explanation of the "frosting". Have seen it on everything you mentioned. Just to make sure I understand what your're thinking, as the tractor warms up (which is the common factor to it dyeing), the warmth might be causing some electrical part(s) to fail? I'll try the torch this weekend. What if that works? Do I have to have one of the grandkids walk along-side the tractor with a propane torch to keep it running (ha). If the torch is a "no go":
1) Will try your coil wire test for no spark.
2) If not spark:- replace the coil with one off of grandpa's working truck.
3) If no go: Try a new electronic "ignitor" points & condenser incase that electronic unit has failed. (Present unit is 3-years old)
4) If no go: Drain the fuel line & carb, and put the sediment-fuel bowl back on, along with in-line fuel filter to try to minimize the chance of any water in the fuel getting to the carb. And, check for no fuel flow restriction to carb from fuel line.
5) Double check carb jet settings
6) If no go: Call carb rebuild company about venturi leg and carb port (see below)
7) Govenor?
8) Massey Harris 44 for sale-"Runs Great for 5-minutes".

Your gas droplet comment makes me wonder about the venturi location in the rebuilt carb. As mentioned, a "leg" of the venturi is partially covering a port of the carb, When I blew out the carb ports last time, this "leg" of the venturi was restricting,, more so deflecting, an even flow of carb cleaner spray through this port. Not certain, but I think this port goes into the air/fuel mixture area of the venturi/carb.

Thanks for your time & consideration, Marsh Bar-Ranch

 

[stevieb49829]

Stevieb; Thanks, for the explanation of the "frosting". Have seen it on everything you mentioned. Just to make sure I understand what your're thinking, as the tractor warms up (which is the common factor to it dyeing), the warmth might be causing some electrical part(s) to fail? I'll try the torch this weekend. What if that works? Do I have to have one of the grandkids walk along-side the tractor with a propane torch to keep it running (ha). If the torch is a "no go":
1) Will try your coil wire test for no spark.
2) If not spark:- replace the coil with one off of grandpa's working truck.
3) If no go: Try a new electronic "ignitor" points & condenser incase that electronic unit has failed. (Present unit is 3-years old)
4) If no go: Drain the fuel line & carb, and put the sediment-fuel bowl back on, along with in-line fuel filter to try to minimize the chance of any water in the fuel getting to the carb. And, check for no fuel flow restriction to carb from fuel line.
5) Double check carb jet settings
6) If no go: Call carb rebuild company about venturi leg and carb port (see below)
7) Govenor?
8) Massey Harris 44 for sale-"Runs Great for 5-minutes".

Your gas droplet comment makes me wonder about the venturi location in the rebuilt carb. As mentioned, a "leg" of the venturi is partially covering a port of the carb, When I blew out the carb ports last time, this "leg" of the venturi was restricting,, more so deflecting, an even flow of carb cleaner spray through this port. Not certain, but I think this port goes into the air/fuel mixture area of the venturi/carb.

Thanks for your time & consideration, Marsh Bar-Ranch

There is a chance the frosting is causing the problem, but I don't know how you would fix that, other than some kind of fabricated shield that would increase the heat around that area from exhaust manifold heat. Then you run the chance of vapor locking the carb once it's warmed up. And if it is frosting up, that means there is gas vapor in the intake manifold. After some more thought about what you have done so far, I think I'd "borrow" a running coil, and try that first. It's an easy thing to do if you have the coil available and may be the answer. Post back with a or and we'll go from there. steve

 

[Bar-Ranch]

Here is what i have tried. Just triple checked the fuel to carb, and through the carb. Didn't run for 5-miutes and quit. Ran for 30-seconds and quit. When dyeing, there was no engine sounds ((sputtering, coughing, backfire, starving for fuel) that would make me think it is fuel related. Pulling or pushing the choke had not effect. Moving the governor arm had no effect. Replaced/repaired some old wires from power to the coil & distributor. The coil was warm, not hot to the touch. No problems with restarting it. One compression stroke and it starts. Did this about 5-times to rule out fuel issues. Even used the hammer/tap method on the carb to make sure the float was not sticking. Could not detect any spark off the coil wire... but pretty hard to be certain doing it solo. Headed out to get another coil to replace the one that is 3-months old.

 

[Bar-Ranch]

regarding the last note, it should have said the noises were not fuel related.

 

[Bar-Ranch]

Steve: Well...talked to the neighbor about using a 12 volt coil if he had one. He said, "Nope, only 6-volt." He used to do small engine repair and was curious about the problem. He said the ethanol fuel is really hard on the rubber type fuel lines. He said the inside the hose lining will sperate from the outside and collapse under any suction from the carb. I told him there was no restrictions anywhere in the fuel system. Obviously, there wasn't based on all the help, advice, and suggested tests tried. He said you might be getting some suction from the carb which is collapsing the inside lining of the hose. I didn't pay much attention to him.

Piked up a new 12-volt distributor coil as suggested at the parts store. On a whim, from what the neighbor said, also go 3 feet of new fuel line. Put on the new coil and it ran excellent for the usually 30 seconds and died. Was ready to go back to the store to get new points and condenser, but paused and thought, what can it hurt, maybe the ole-timer was right. So.., put on the new piece of fuel line. The old fuel line ply's must have been separated inside the hose. The old hose was just a little over a year old. There was no visible collapse of the exterior of the old hose while the tractor was running for its 30-or-so-seconds. Prior to the new hose, I had even shortened the old fuel line to the point of it being taunt between the gas tank and the carb to rule out air locks.

Have not put the tractor through it's paces yet, but ran it for 5-minutes without trouble. It is the mud season in Wisconsin, so it will be a few weeks before any work can start.

Oh to ponder...when it ran for about 5-minutes a few weeks ago it was freezing weather here. The fuel hose was likely rigid from the cold. As the engine warmed, the fuel line warmed and it must have became more pliable and the linear would separate and collapse, and not run for more than 30-seconds there after. Just guessing.

Thanks for all the advice and feedback.

Marsh
Bar-Ranch

 

[stevieb49829]

Steve: Well...talked to the neighbor about using a 12 volt coil if he had one. He said, "Nope, only 6-volt." He used to do small engine repair and was curious about the problem. He said the ethanol fuel is really hard on the rubber type fuel lines. He said the inside the hose lining will sperate from the outside and collapse under any suction from the carb. I told him there was no restrictions anywhere in the fuel system. Obviously, there wasn't based on all the help, advice, and suggested tests tried. He said you might be getting some suction from the carb which is collapsing the inside lining of the hose. I didn't pay much attention to him.

Piked up a new 12-volt distributor coil as suggested at the parts store. On a whim, from what the neighbor said, also go 3 feet of new fuel line. Put on the new coil and it ran excellent for the usually 30 seconds and died. Was ready to go back to the store to get new points and condenser, but paused and thought, what can it hurt, maybe the ole-timer was right. So.., put on the new piece of fuel line. The old fuel line ply's must have been separated inside the hose. The old hose was just a little over a year old. There was no visible collapse of the exterior of the old hose while the tractor was running for its 30-or-so-seconds. Prior to the new hose, I had even shortened the old fuel line to the point of it being taunt between the gas tank and the carb to rule out air locks.

Have not put the tractor through it's paces yet, but ran it for 5-minutes without trouble. It is the mud season in Wisconsin, so it will be a few weeks before any work can start.

Oh to ponder...when it ran for about 5-minutes a few weeks ago it was freezing weather here. The fuel hose was likely rigid from the cold. As the engine warmed, the fuel line warmed and it must have became more pliable and the linear would separate and collapse, and not run for more than 30-seconds there after. Just guessing.

Thanks for all the advice and feedback.

Marsh
Bar-Ranch

I've seen that happen with "old school" hoses and ethanol fuel. It's also really hard on the rubber tips that are sometimes on the inlet float needle. I run non-ethanol premium fuel in all my small engines for that reason. Sounds like you got it. Let us know how it works, when the Wisconsin mud will let you at it. steve

 

[Bar-Ranch]

Steve, a question, before I had the carb rebuilt, there was gas pooling in the carb, at the air inlet.. Was that likely from the rubber tip of the float seat being bad due to ethanol? Started running premium in all small engines as well. Prior to that, I just planned on putting on new fuel lines ever spring.

 

[stevieb49829]

Steve, a question, before I had the carb rebuilt, there was gas pooling in the carb, at the air inlet.. Was that likely from the rubber tip of the float seat being bad due to ethanol? Started running premium in all small engines as well. Prior to that, I just planned on putting on new fuel lines ever spring.

It could be the needle not seating totally when the float pushes it to the top of its travel. That could be the needle, the seat, or the float height setting or the float hanging up, or debris between the needle and seat from a dirty tank or fuel line. All updraft carbs tend to settle gas out of the airstream, which ends up at the lowest place in the throat. Most of these old cast carbs have a sintered insert in the very bottom of the throat to allow this gas to slowly seep out of the carb.