MF135 gas, I'm starting to hate it!

Ncnative

Member
Yesterday I mowed pasture for about two hours and it ran great. This morning it did not want to start, got it running but its like it would run just until the fuel in the carb ran out then it would shut down. I pulled the sediment bowl off to check for fuel flow, the flow looked fine. I could not get the bowl to reseal so I went to the dealer and got a new rubber seal. I noticed when putting the sediment bowl back on if gas was running into the bowl as I was tightening the bowl nut (to seal the bowl) as the bowl sealed the gas would completely stop flowing??? If I loosened the bowl fuel would start to flow again...is this normal? almost what I would call a vacuum lock. I could let the tractor sit for a couple minutes and it would start right up and run for 2-3 minutes then shut off until i let it sit for another couple minutes then I could repeat the process over and over
Thanks in advance for any assistance
 
Take the fuel line loose at the carb and see what kind of fuel flow you have there if good flow there for a couple of minutes, then the problem is in the carb.
Richard in NW SC
 
That's normal for gas to stop flowing when tightening bowl.I always let bowl fill
before tightening. Take plug out of bottom of carburetor and see if you have good flow.
Also you may have some water. If you have flow then it's electrical. Have you replaced
points and condenser? Also check gap on points this could be reason it didn't want to
start. Set at 23.
 
Pull the fitting out of the carb, some have a screen on the end that goes into the carb, your restriction may be their.
 
Here is why the sediment bowl will not fill with gas when you tighten up the bale. Two elements or things can not be in the same place at the same time. The bowl is full of air so the gas can not be there due to the float in the carb closing off the flow.

As for your problem pull the carb drain plug and make sure you have a good steady flow of gas out of the bottom of the carb that will fill a pint jar in less then 3 minutes. If flow is slow work your way back to where it is clogged up. If by chance you have an in line filter in the system throw it as far from the tractor as you can and your problem will go with the filter
 

As miner09 said, pull that plug in the bottom of the carb bowl. The gas flow should fill a pint jar in less than two minutes. If it doe not, do as Jo Bird said and pull the fuel line fitting out of the carb. It has a screen that is probably plugged up. I had the same thing happen to me. Below is a pic of that fitting. It's available at TSC if you have one near you. This screen does it's job and keeps the crap out of your carb.

U9Q5MAQ.jpg
 
(quoted from post at 11:22:59 05/26/18)
As miner09 said, pull that plug in the bottom of the carb bowl. The gas flow should fill a pint jar in less than two minutes. If it doe not, do as Jo Bird said and pull the fuel line fitting out of the carb. It has a screen that is probably plugged up. I had the same thing happen to me. Below is a pic of that fitting. It's available at TSC if you have one near you. This screen does it's job and keeps the crap out of your carb.

U9Q5MAQ.jpg
Thanks for the responses. I will start at the carb drain tomorrow to see how much flow I have thru the carb then work backwards as suggested. And I do believe there is an inline filter, not 100% sure but will check that also. Thanks again
 
Thanks for all the replies. I will check the fuel flow thru the carb tomorrow. I fairly sure it’s a fuel issue.
 
Update:
The problem still exists. Fuel flow out of the carb bowl drain filled a pint jar in exactly 1.5 minutes. Fuel flow out of the fuel line ahead of the filter filled the pint jar in 45 seconds.
The tractor starts and runs for between 2 and 5 minutes then just shuts off, will not start back right away. I have shut off the fuel as soon as it starts to shut down then checked for fuel in the carb bowl, it's always full? when it would not start I checked the spark from the coil and from the #1 spark plug both had very strong spark? It that some kind of fuel shut off on the bottom of the carb with a single wire going to it? I checked and it has 12v when the ignition is on, I assume that's what I should see? Seems weird is that if it were a carb issue why does it start and run so good for the 2 -5 minutes?
 
Sounds like it has one of those solenoid to open main jet shut offs and those can be nothing but trouble. When I can find the parts I remove them and replace them with adjustable main jet set ups so as not to be a problem. If it does not work like it should it can do just as it is doing
 
Looks like it is an electrical issue after all. This morning first thing it would not start, I pulled the coil wire off and no spark, as I'm putting the wire back on the coil and the engine is still rotating I feel it bite me. I move the coil wire end back close to a ground and turn the engine over and voila spark! Stick the wire back in the coil and it fires right up, runs a minute or so then dies, check for spark again an there is none, thirty seconds later the spark is back. I ran a wire directly from the battery to the coil and it runs without shutting off. Now it's just a matter of figuring out if it's the ignition switch or somewhere between the switch and coil.
 
(quoted from post at 11:30:30 05/29/18) Looks like it is an electrical issue after all. This morning first thing it would not start, I pulled the coil wire off and no spark, as I'm putting the wire back on the coil and the engine is still rotating I feel it bite me. I move the coil wire end back close to a ground and turn the engine over and voila spark! Stick the wire back in the coil and it fires right up, runs a minute or so then dies, check for spark again an there is none, thirty seconds later the spark is back. I ran a wire directly from the battery to the coil and it runs without shutting off. Now it's just a matter of figuring out if it's the ignition switch or somewhere between the switch and coil.

Glad yer gettin somewhere.
 
(quoted from post at 12:16:32 05/29/18)
(quoted from post at 11:30:30 05/29/18) Looks like it is an electrical issue after all. This morning first thing it would not start, I pulled the coil wire off and no spark, as I'm putting the wire back on the coil and the engine is still rotating I feel it bite me. I move the coil wire end back close to a ground and turn the engine over and voila spark! Stick the wire back in the coil and it fires right up, runs a minute or so then dies, check for spark again an there is none, thirty seconds later the spark is back. I ran a wire directly from the battery to the coil and it runs without shutting off. Now it's just a matter of figuring out if it's the ignition switch or somewhere between the switch and coil.

Glad yer gettin somewhere. A man and his tractor should have a good relationship.
 
One way if you can do so easily is to put the hot wire from the battery to the ignition side of the ignition switch. If it runs that way then bad switch. If it does not run that way wire between switch and coil is bad. Or you could also jump across the switch terminals and it too would tell you if the switch was bad
 
(quoted from post at 12:29:01 05/29/18) One way if you can do so easily is to put the hot wire from the battery to the ignition side of the ignition switch. If it runs that way then bad switch. If it does not run that way wire between switch and coil is bad. Or you could also jump across the switch terminals and it too would tell you if the switch was bad

Thanks Old for your help/advice, especially the simple explanation about why the gas stopped flowing into the sediment bowl, I guess I should have paid mor attention in 7 th grade science????

I ran a wire directly from the battery to the coil and mowed for about 1 hour today. I’m thinking the problem is not in the switch because if the switch were dropping the “run” 12v then the fuel shutoff solenoid would engage and shut off the fuel and the tractor would shut off even with the coil circuit bypassed. I bypassed the original circuit from the switch to coil but I did not bypass the circuit from the switch to the fuel shutoff solenoid and it ran fine for the hour or so when I mowed today. I thinking of just adding a new circuit using a simple relay.
 
(quoted from post at 12:29:01 05/29/18) One way if you can do so easily is to put the hot wire from the battery to the ignition side of the ignition switch. If it runs that way then bad switch. If it does not run that way wire between switch and coil is bad. Or you could also jump across the switch terminals and it too would tell you if the switch was bad

Thanks Old for your help/advice, especially the simple explanation about why the gas stopped flowing into the sediment bowl, I guess I should have paid mor attention in 7 th grade science

I ran a wire directly from the battery to the coil and mowed for about 1 hour today. I’m thinking the problem is not in the switch because if the switch were dropping the “run” 12v then the fuel shutoff solenoid would engage and shut off the fuel and the tractor would shut off even with the coil circuit bypassed. I bypassed the original circuit from the switch to coil but I did not bypass the circuit from the switch to the fuel shutoff solenoid and it ran fine for the hour or so when I mowed today. I thinking of just adding a new circuit using a simple relay.
 
Could still be the switch since it would run some times and not others and the solenoid on the carb may or may not have been opening. When you hot wire it you back feed every thing from the coil back to the switch unless you unhook the ignition wire from the coil. Electric's for me most of the time are child's play but I was a Navy E.T. so did a lot of stuff with electronics. But I will say I am having a hard time with a 12 volt conversion on a Case VAC
 
(quoted from post at 08:26:03 05/30/18) Could still be the switch since it would run some times and not others and the solenoid on the carb may or may not have been opening. When you hot wire it you back feed every thing from the coil back to the switch unless you unhook the ignition wire from the coil. Electric's for me most of the time are child's play but I was a Navy E.T. so did a lot of stuff with electronics. But I will say I am having a hard time with a 12 volt conversion on a Case VAC

Yes I did disconnect the coil wire.
 
Ok so that says the ignition switch is giving power to the carb solenoid. So you have a bad wire between the ignition switch and the coil or if the ignition switch has say one place that the carb solenoid come off of and another for ignition the switch could still be bad.
 
(quoted from post at 11:23:44 05/30/18) Ok so that says the ignition switch is giving power to the carb solenoid. So you have a bad wire between the ignition switch and the coil or if the ignition switch has say one place that the carb solenoid come off of and another for ignition the switch could still be bad.

I think that you are correct about a bad wire between the coil and ignition switch. The switch only has one “run” terminal that feeds power to everything that needs 12v when the tractor is running. I mowed 2+ hours today with no issues using the direct coil-to-battery wire setup.
 
Well if it run hot wired and have no problems move that hot wire from the battery to the hot side of the ignition switch when on and see if it run then. If it does not you have a bad switch but if it run that way then the wire is bad. I've seen switches that acted oddly because of to many amps going threw them and then not working due to amp draw being to high
 
(quoted from post at 09:25:08 05/31/18) Well if it run hot wired and have no problems move that hot wire from the battery to the hot side of the ignition switch when on and see if it run then. If it does not you have a bad switch but if it run that way then the wire is bad. I've seen switches that acted oddly because of to many amps going threw them and then not working due to amp draw being to high

I’ll try that, thanks
 
(quoted from post at 09:25:08 05/31/18) Well if it run hot wired and have no problems move that hot wire from the battery to the hot side of the ignition switch when on and see if it run then. If it does not you have a bad switch but if it run that way then the wire is bad. I've seen switches that acted oddly because of to many amps going threw them and then not working due to amp draw being to high

I’ll try that, thanks
 

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