MF acceleration problem

krep

Member
I just got my friends MF 150 running again. I first worked on it back in the 80s, and it had run fine for years afterwards. He pulled the starter 2-3 years ago and it has sat out unDer a tree in Michigan weather for a while. Of course he had also pulled the carburetor and linkage and fuel line among other things to get access. So I went over yesterday and put the new starter on, and hooked everything going up and put new fuel in it and it started. Anyway, after a while it idled well enough, but if you increased throttle, it spit and popped and gradually popped on one or two cylinders until it finally sped up and ran on all 4 again. It ran like it was really really lean. I am confused as to why it is doing this. Could it be a problem with the distributor, like the points are shot from moisture? It also has some kind of electronic thing on the bottom of the zeneth carb. Could that be shutting down the fuel? The fuel line to the carb is not restricted. Any ideas? Thanks
 
It could be the points are corroded or need adjusting. The centrifugal advance could be stuck or slow responding. Also check the shaft bushing for wear, needs to have very little side play, or the points can not be set.

Not sure what the electronic part on the carb would be, possibly an anti-dieseling device to cut the fuel when the ignition is off. If that is what it is, and it were bad, it would not run at all. If you suspect it's too lean, try a partial choke, see if that improves the performance. If it does, try adjusting the main jet richer. When properly adjusted, you should be able to set the engine to full speed, close the throttle down to idle, release it and the engine will spin up to governed speed without hesitating, a puff of black smoke is normal.

And it could have some sticky valves from sitting. How does the oil look? Any signs of moisture in the engine? An oil change would be a good idea. Also want to check the transmission for water. Sitting out it probably has some water in it. It gets in around the shifter boots and the older models had a rubber boot around the upper link under the seat, I suspect that one does too.
 
I didn't have much time today, but passed by and started the tractor. I tried the partial choke suggestion and it didn't seem to make a difference so I will work on the distributor next time I pass by. Oil change you say. He said he has never done one. I almost kicked him. He's had it about 30 years and no oil change. Good God, how do I get in the middle of these things.
 
30 years and no oil change OMG.Betcha he didn't clean the air filter either (hint,hint) Like to see the inside of that engine!
 

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