135 Gasoline model gas problems

[TnAndy]

Trying to help a neighbor of mine with an older MF135 with gas engine. It only ran enough for him to get it over to my shop with the choke pulled all the way out....push it in even a little, and it would die. He bought the tractor from a guy that almost never used it....only 600hrs on the meter, it has spent a lot of time parked in a shed over the decades.

What we've done so far:

Pulled the carb, a Zenith model, took it apart, soaked in a gallon can of carb cleaner over night, blew every passage out I could see to blow out, used a carb kit to rebuild...but it had no new jets...mainly gaskets.

We have also removed the fuel tank (to install new spark plugs), cleaned it out.

Installed a new glass fuel bowl on the tank (the cutoff valve was leaking on the old one), blew out the fuel line from the bowl to the carb, installed a new fuel filter at the carb, have good, clean fuel flow TO the carb.

Checked the solenoid in the float bowl....it retracts as it should when power is applied to it.

New air filters, inner and outer.

Replaced points, plugs, plug wires, condenser, cap (which WAS badly pitted at the 3 contact points), rotor.

Results ?

Can now get it to idle once warmed up with no choke....but at 1500-2000 rpm, still needs about 1/2 choke, or it spits/sputters/dies....but runs fine with the choke half pulled out.....which indicates to me still not getting gas thru the main jet (and I have no idea which of the jets IS the main jet). It's definitely running better than when it limped in my door, but it's certainly not up to par yet.

Carb only has what I think is an air screw (according to one pic I found) on the side next to the inline fuel filter. I set it 1 1/2 -2 turns back out from bottomed all the way in, doesn't seem to affect idle until I back it way out....like 5 turns, then it wants to die at idle. No other external adjustments I can see other than I could adjust the throttle cable connect point....but haven't....seems that would only increase or decrease the idle speed.

Would welcome any help at this point.

Thanks.

Andy

 

[Sawyer Rob]

I think that carb needs a trip through one of those "sonic" cleaners...

SR

 

[jaxs]

From your description (no adjustmenmet screws) you may well have the wrong carb. I haven't worked on many 135s but have done several T0s and MFs. All of those had two adjustment screws and non had filter at carb nor solenoid you described. See if you can cross referance the carb model #. That same Continental engine was used in several applications with various fuel,ignition and governor arrangements that are not interchangeable unless everything is changed togeather. Did you confirm venturi was installed correct side up? If there was no venture in throat you definatly have wrong carb. If ignition is off bad enough it will not run on anything short of a rich mixture. Make sure it's in time,advance weights are not stuck or missing parts and spark is strong. For what it's worth,that is a good model tractor so it's worth investment if new parts are required.

 

[TomSeller]

I once bought a generator with an engine that had no adjustment screws. Ran but not well. I finally bought a new carb which came with normal adjustment screws. I looked closely at the old crab and after wiping grease away I could see where the screws USED TO BE. Runs fine now.

 

[TnAndy]

From your description (no adjustmenmet screws) you may well have the wrong carb.

Thanks for the reply !

Pretty sure it's the carb that came on the tractor.....I see no reason they would have changed it given the low hours. Didn't look to me like it had ever been off the manifold.

There is a 'port' hole on the back side (left side facing tractor operator) where an adjustable jet screw might go, but it is plugged with a metal cap, as are a couple other places on the carb body....doesn't look like one was ever there. Neighbor's book does show an adjustable needle screw on both the front and back side (right and left side). BUT when shopping for a carb rebuild kit, it appears several different carbs were used on them....this one is definitely a Zenith....found that in the carb body when the crud was removed.

The venturi is there, and "murphy proof"....only goes one way the base seats to the carb body...you can't get the carb halves back together if not seated right. (Yeah....ahahhaa....ask me how I know)

I did not time the ignition, but I do have an old timing light (wow....haven't used it in 25 years or more). I looked for timing marks on the front crankshaft pulley, as well as some kind of mark, arrow, slot, etc in the front casting....rotated the pulley a full 360 degrees with a real good flashlight on it, and I don't see a thing resembling a timing mark. I did read somewhere about a plug you have to pull out (of the engine case ?) to see the timing marks, so I looked for something like that and see nothing. The book the neighbor had was useless...says "take to a dealer for engine timing".

I thought about getting #1 piston to TDC, and simply make my own mark on the front pulley/case....if nothing else, I could see if the distributor is advancing the timing when rev'ed up.

 

[TnAndy]

I think that carb needs a trip through one of those "sonic" cleaners...

SR

Hmmm....will have to call around and see if I can find someplace that does that. Thanks.

 

[jaxs]

The timeing marks are on flywheel. Cover is mounted in similar position and fashion as starter motor,on other side. Tractor Supply Company stock's "IT Manual".

 

[TnAndy]

Ah...the flywheel end....yeah, wasn't looking there, for sure. Thanks !

 

[BobG_in_VA]

You haven't identified the engine...is it a 3 cyl or a 4 cyl? 3 is a Perkins/4 is a Continental. Continental's came with M/S carb...mo' info needed... BobG in VA

 

[jaxs]

You haven't identified the engine...is it a 3 cyl or a 4 cyl? 3 is a Perkins/4 is a Continental. Continental's came with M/S carb...mo' info needed... BobG in VA

Whoaooo,if it's a Perkins there's the problem,,,,,,,,,,,,,,,,,,,,,,,it didn't have a carburetor from the factory.:tractor: Yes,all gasoline models came with MS,partly why I brought up improper carb. Zenith replacements can be had but how often does one discard the carb on old tractors rather than rebuild? That solenoid and in carb filter coupled with Zenith sound's like carb was designed for a genny or irrigation pump.

 

[TnAndy]

It's 3 cylinder....have no idea as to brand/model of engine in it.

The carb filter is external....mounts vertical, and screws into an adapter screwed into the right side (front of tractor) of the carb.

Pretty sure it's the original carb.....that silver paint on the intake manifold WAS also all over the carb as well, like it was spray painted all at the same time. Paint desolved off in the carb cleaner soaking.

Here are a few pics:

Carb side:

Carb closeup:

Other side of engine:

 

[Jerry/MT]

Thanks for the reply !

Pretty sure it's the carb that came on the tractor.....I see no reason they would have changed it given the low hours. Didn't look to me like it had ever been off the manifold.

There is a 'port' hole on the back side (left side facing tractor operator) where an adjustable jet screw might go, but it is plugged with a metal cap, as are a couple other places on the carb body....doesn't look like one was ever there. Neighbor's book does show an adjustable needle screw on both the front and back side (right and left side). BUT when shopping for a carb rebuild kit, it appears several different carbs were used on them....this one is definitely a Zenith....found that in the carb body when the crud was removed.

The venturi is there, and "murphy proof"....only goes one way the base seats to the carb body...you can't get the carb halves back together if not seated right. (Yeah....ahahhaa....ask me how I know)

I did not time the ignition, but I do have an old timing light (wow....haven't used it in 25 years or more). I looked for timing marks on the front crankshaft pulley, as well as some kind of mark, arrow, slot, etc in the front casting....rotated the pulley a full 360 degrees with a real good flashlight on it, and I don't see a thing resembling a timing mark. I did read somewhere about a plug you have to pull out (of the engine case ?) to see the timing marks, so I looked for something like that and see nothing. The book the neighbor had was useless...says "take to a dealer for engine timing".

I thought about getting #1 piston to TDC, and simply make my own mark on the front pulley/case....if nothing else, I could see if the distributor is advancing the timing when rev'ed up.

Does it have a Continental Engine? The Z series Continental engine had their timing marks on the flywheel. Look under the starter for a hole where you can see the flywheel. Sometimes they have a rubber plug in the hole.

Initial timing 6 °BTDC IIRC. To static time ,pull the plugs (makes it easy to turn) rotate the engine until #1 cylinder is on compression stroke and look in the hole below the starter to find the timing mark. Set the timing mark in the notch. Loosen the distributor so you can rotate it. the rotor should be point very near to the # 1 plug wire terminal. Put a paper clip in the #1 spark plug boot and hold that near a good ground and turn on the ignition. Rotate the distributor back and forth until you hear the spark snap. At that point you are statically timed. You may have to do this several times and when you feel you have it right, tighten down the distributor, put the plugs back in and start it up.

 

[Smokepole62]

Yes, that is a Perkins 3 cyl gas engine. Continental engine has the exhaust on the right side. It sounds like you have a jet still plugged somewhere, either the high speed main or the
idle low speed jet. If it sat a long time, the carb probably gunked up good in the passages. You may have to take it apart again. Another possibility is a vacuum leak between the carb and the intake manifold. Rubber boots and intake gaskets do dry out over time, especially with intermittent use.

 

[Sawyer Rob]

IF it was a timing problem, then it wouldn't have run "better" with the last carb cleaning...

Find a sonic cleaner and finish the job... Even buying a carb "rebuild" kit for that carb wouldn't be too bad of an idea...

SR

 

[deanocraft]

I would probably put some Sea Foam in the tank and run it for a good while. Since it will run, the additive may clean out the jets for you!

Dean

 

[Birdhunter1]

Your problem describes is likely to be there is an air leak between the intake manifold and the head. It will run fine when cold, when it starts to warm up you need to pull the choke out until eventually you have the choke all the way out.
To find it; get the engine warm to where it starts sputtering, and use carb cleaner to spray around the intake. If it runs fine for a few seconds after you spray it you have found your leak. Keep spraying in areas to isolate the leak.

 

[TnAndy]

I would probably put some Sea Foam in the tank and run it for a good while. Since it will run, the additive may clean out the jets for you!

Dean

That is the current plan.....he took it over and bushhogged his place for several hours yesterday, I haven't talked to him since he left here yesterday, but did see he managed to get the whole place mowed. We dumped a can of Sea Foam and some Marvel Mystery Oil in with a tank of gas.

 

[TnAndy]

Your problem describes is likely to be there is an air leak between the intake manifold and the head. It will run fine when cold, when it starts to warm up you need to pull the choke out until eventually you have the choke all the way out.
To find it; get the engine warm to where it starts sputtering, and use carb cleaner to spray around the intake. If it runs fine for a few seconds after you spray it you have found your leak. Keep spraying in areas to isolate the leak.

Actually, the symptoms are just the opposite....runs better with less choke as it warms up good. But we'll sure try your suggestion and spray some cleaner around the intake manifold. I feel fairly sure it's still a carb blockage problem

Thanks.

 

[TnAndy]

I tend to agree.

We DID get a carb kit for it before I soaked it in the can of cleaner, but about all you get in one are the gaskets....no new jets except the one external needle jet, which I did install in place of the old one.

 

[PatrickS2222]

Actually, the symptoms are just the opposite....runs better with less choke as it warms up good. But we'll sure try your suggestion and spray some cleaner around the intake manifold. I feel fairly sure it's still a carb blockage problem

Thanks.

I've never had one of those carbs apart - all 135s I've ever worked on are diesel. But looking at you great close-up pics of the carb, that brass hex-headed plug screwed into the bottom at an angle could either hold the main jet or provide access to it. I'd remove it and look to find the jet - a full-blooded shot of compressed air through it or up into the hole it screws into may work wonders. There's not much to this type of carb - an air-blaster held against the opening of the passage should dislodge it - especially since it has had a good soaking and then fuel in it for some time.
Please keep us informed so others can know you've fixed it, and also benefit from your hard work.
Cheers, Pat.