MF 36 swather starting issue

Dave H (MI) · Aug 6, 2020

Started fine earlier in the month but would stall after 10 seconds or so. Then would not start at all. So I checked and adjusted the plugs. Has good spark. Replaced the fuel filter. Everything points to the carb so I pulled the air intake off and some gas spilled out. I drained the carb down a bit, sprayed some starter fluid in it and it fired to life. Ran about 10 seconds and stalled and spit gas out the air intake. This engine has a fuel pump, not gravity fed and I have little know how about these. It's a weird carb. Shine a light in the air intake and you can see the butterfly for the throttle. Doesn't look like there is anything in there. Did not pull carb pending responses here. Pics of engine and carb attached. It's a great starter but not sure why it is flooding so bad. Any ideas?

jal-SD · Aug 6, 2020

Looks like it's the industrial version of the Chevy II's 4 cylinder engine. Sounds like it needs a carb cleaning, probably crap in the needle/seat, might be a float gone bad. I think they had a varnished styrofoam float.

Steve@Advance · Aug 6, 2020

Easy check on the fuel pump.

See the rubber hose right below the choke cable? Disconnect it an direct it into a clean glass. You may have to put a longer hose on it.

Hold the hose in the glass while your assistant cranks the engine through. If it starts, fine, if not just crank on it a few seconds.

The pump should give a strong, full stream, shot of fuel every other time the engine turns through. The pump is driven off the cam is why it's every other rotation of the crank.

If there is little or no flow, check the rubber hose between the tank and the pump for rot or collapse. Probably another hose at the tank.

Good chance the pump is bad though.

That's a common pump, fits Chevy II 153, 194, 230 mid 70's.

There should be a number stamped on the edge of the mount flange. Try to get a Delco pump instead of an aftermarket.

Dave H (MI) · Aug 6, 2020

Steve, if the pump is bad would the carb flood like that? Help me to understand, do pumps go bad and send too much fuel to the carb or...?

Steve@Advance · Aug 6, 2020

I saw that you sprayed starting fluid and it started.

A flooding carb will not respond to starting fluid, that will only make it worse.

If you kept spraying the starting fluid, would it keep running?

If so, that is lack of fuel, not flooding. Many times an engine that is starving for fuel will cough back out the carb, and it may spit some gas back, not necessarily meaning it is flooding.

A flooding carb will display black stinky exhaust, run better at wide open throttle, load up and die at idle, overflow and drip gas, poor fuel economy, black foul plugs, will even raise the oil level if ran long enough.

A lean carb will sometimes idle, but not take throttle, cough back, no exhaust smoke.

To answer your question, no a mechanical pump can not make too much pressure.

Princeton Bill · Aug 7, 2020

Dave after looking at that hose I’d replace it before I did anything else. It looks like it might be soft and somewhat collapsed. Of course I know pictures can be deceiving.

MARK ROBKE · Aug 7, 2020

I'm kinda leaning the same way as Jal-sd. If the carb is flooding then probable the float stuck or sank, or needle and seat has dirt in it. Were your plugs wet with gas when you pulled them? Was the gas you drained out of the float bowl dirty? Mark.

MF 36 swather starting issue

Dave H (MI)

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jal-SD

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Steve@Advance

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Dave H (MI)

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Steve@Advance

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Princeton Bill

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MARK ROBKE

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