Tractor Engine Quits After A Couple of Hours

[rlk]

I have a gas MF 35 that I have had for about 15 years. I bought it used, and have used it extensively since buying it. The engine has developed a problem that has me stumped.

A week ago, after running it for about 3 hours raking the area around the pond with a landscape rake, the engine quit. Sounded like it was out of fuel. I messed with it for a few minutes, then tried to start it again. Started fine and ran for about 5 minutes then sputtered again like there was trash in the fuel line, or like it was giving out of fuel. This time I pulled the choke out a little, and it recovered for a few minutes, then sputtered again. Pulled the choke out again for a second or too, but this time it did no good - the engine quit.

Removed the gas cap to make sure there was fuel in the tank. Apparently the tank was pressurized because there was quite a sound as either air escaped the tank, or rushed in. Saw there was plenty of fuel in the tank, so removed the sediment (spelling) bowl. When I did this, the fuel gurgled a few times, then fuel ran out. Put the bowl back on, and the engine started fine. Made it to the shop and let it sit over night.

Next morning it started up fine and ran for a couple of hours before doing the same thing again. Engine sputtered some, I pulled the choke a few times, it recovered for a short time, then quit. Gas tank was pressureized. Removed the sediment bowl, gurgled again, then fuel ran out. Engine started up, but would only run for 20 seconds or so before cutting off again.

I decided I had trash in the fuel, and/or something was wrong with the sediment bowl assembly.

Found a replacement sediment bowl assembly. Took the old one off, drained the tank, then installed the new one. Also installed a new gas line to the carburetor. Engine started and ran fine for the rest of the day. I thought the problem was solved.

Next day, after a couple hours of raking, same thing happens again.

Talked to a Massey Furgeson parts person, and he suggested rebuilding the carburetor. Yesterday, I picked up a kit and rebuilt the carburetor. Today, after about 3 hours, the same scenario takes place again.

Finally make it back to the shop and let it sit outside while I talked to my neighbor. After about an hour, it started and ran long enough for me to get it into the shop. It might have run longer, but it was the end of the day, and I was tired of messing with it.

Originally I thought the problem was fuel related because pulling the choke out some when it sputtered would help it run a little longer. Now I'm not too sure.

Could it be the condenser or coil is getting hot and failing? These are not very expensive items, and are fairly easy to replace.

Could it also be vapor lock? Not sure how to fix a vapor lock problem on a tractor, but I used to have a Volkswagen that would not start when it was hot. Everyone said it was vapor lock - ended up trading it without ever fixing it.

Before doing anything else, I wanted to see if any of you had an idea what the problem may be.

 

[MossRoad]

On my IH2500B I have an electric solenoid that shuts off the fuel when the key is turned off. The thing gets flakey and has to be replaced every few years. It gave similar simptoms. Do you have a solenoid like that? Just a thought.

 

[chim]

Just a thought. From what you said - "air escaped the tank, or rushed in" are you sure tha tank was pressurized, or is it possible it was under a vacuum? If the tank can't breathe, mebbe the engine can't draw fuel. That would kinda explain why the choke made a differnece for a short run. This could be ruled out as a problem by removing the fuel cap when it dies the next time. If it still won't run, forget this and look for something else......................chim

 

[Casimir]

rlk--

It does sound like a fuel problem, rather than an electrical problem. You say that when you remove the sediment bowl, it gurgles, then gas runs out and it will start and run again. Sounds to me like you may have something floating in the gas tank that gets sucked up against the intake, creating a vacuum in the line. When you allow air in the other end of the line, it may be back flushing whatever is clogging the intake inside the tank.

But you also mentioned that the tank seems pressurized or air rushes into the tank when you remove the cap. Is the cap vented? If it is, and is supposed to be, something may be clogging the vent in the cap. As long as there is plenty of air in the tank, the fuel could flow to the engine until enough vacuum built up in the tank to keep the fuel pump from pulling the gas from the tank.

I would check to see if the cap is vented or the tank is otherwise vented, with something clogging the vent. A new fuel cap may be cheaper and faster to change than a coil. Next would be to check for debris in the tank that may be clogging the fuel line intake. This might require removing and draining the tank to get any loose debris out of the bottom of the tank.

Good luck. These things can really be frustrating. /w3tcompact/icons/hmm.gif /w3tcompact/icons/sad.gif

 

[Hydraman]

Try loosening the gas cap just a bit-- sounds like a POSSIBILITY that your tank is going on a vacuum-- saw this happen w/ one other outfit one time. My father had a '55 plymouth that did this when we were all on vacation. He found a good man that pointed him to the problem!! The rushing air sound and the gurgleing sound are what make me suspicious. Good luck!

 

[rlk]

MossRoad

Thanks for the suggestion. No solenoid that I'm aware of that controls fuel. The gas line is a straight shot from the sediment bowl to the carburetor.

 

[rlk]

Chim, Casimir, Hydraman

Thanks for your replies. Sounds like the consensus is the tank is getting somehow going on vacuum, or perhaps trash in the tank. I drained the tank when I replaced the sediment bowl, but did not flush it. If it is trash in the tank, I don't see how that could cause a vacuum, but you never know.

I have never changed the gas cap. Looking at it previously, I thought it looked a little wierd in that there are no holes in it. Not sure how air is supposed to enter the tank to replace the fuel being burned. I have not found anything else connected to the tank that looks like a vent.

The air I hear must be air rushing in to relieve the vacuum. Tomorrow I'll try running with the gas cap loose to see if that helps.

Again, thanks for all your help. It is really good to have a place to discuss problems like this.

Muhammad, thanks for providing such a great site!

 

[karmakanic]

a few thoughts Bob,

Chim is right on about the tank venting. See if it makes a difference if the cap is removed.

Does the tractor use a fuel pump, or is it gravity feed to the carb? Fuel pump could defnitely cause the problem.

Some ignition system problems could also cause the symptoms you describe. Pulling the choke out richens the mixture which reduces the load on the secondary part of the ignition. A marginal coil for instance might be influenced by this. I've never seen a condensor cause it, but I'm old enough to not discount anything when it comes to engines. But condensor would usually cause arcing of the points,,,might look for a "mountain" on one side of points, and valley on other for evidence of weak condensor.

If removing the fuel tank cap doesn't have any effect, I'd go to the auto parts store and buy one of those inexpensive "spark testers". You put these in the circuit between distributor and spark plug. See if you're loosing ignition or fuel when the problem occurs, and go from there.

BTW, a quick note about rust in the tank. Most radiator/gas tank shops offer a process to seal the insides of the tank with a plastic sealer. Any older farm vehicle needs this done, especially those with gas engines, or you'll be fighting continual rust in the fuel system problems.

HTH,
Dave

 

[bgott]

If the tank is like the one on an 8N it'll have a vent built into the top of the tank, not a vented cap. They did this to keep gas from sloshing out when the tank is full. A vented cap is not designed to have gas sloshing on it. Think about what happened on those old cars when you over filled them. The vent on the 8N is a hole in the top of the tank with a steel bowl welded over it. The steel bowl has a hole at the opposite end from the hole in the tank. That way any gas that sloshes out of the hole in the tank can drain back without running down the outside of the tank. Stick a vented cap on it, or drill a little hole in your old cap and see if the problem goes away. Make sure the tank is only half full, most people run the vented cap and ignore the drips but it could possibly drip down on your exhaust pipe and form the subject of a whole 'nother thread.

 

[TBone]

My guess would definitely be a venting problem on your gas tank. I grew up with an 8N ford that did that very thing. Cleaned the vent out and it was OK.

This website <A target="_blank" HREF=http://hometown.aol.com/bigdean62/index.html>http://hometown.aol.com/bigdean62/index.html</A> will connect you with a guy that was a Massey mechanic for 27 years and knows his stuff about the older tractors.

Good Luck!

TBone

 

[Rubintropfen]

I have some experience with a few older tractors. The problem could be due to several things. I suggest you take a spark plug wrench with you the next time you run the tractor and when it dies immediately pull a plug, ground it to the block, and check for spark while trying to restart. If you are not getting a strong, bright spark then concentrate on the ignition system first. Another silly thing to try is running the tractor in the dark and looking at the spark plug wires for "stray" sparks. Replace all the spark plug wires if you got that issue (don't forget the coil to distributor wire, too). Make sure you set the timing correctly after monkeying with the points/condensor.

Another source of fuel system problems that you didn't discuss is the tank itself, and the screen in the tank. Rust in the tank could be clogging the screen, or even getting into the fuel line. You might just be able to drain the tank, remove the screen, and clean it, but if it is all rusted up you might need to seal the tank. I think the tank should either have vents, or a vented cap (not sure which on an MF35). If the vents are plugged then open 'em.

There is always the possibility of a "strange" problem, too. I once had a distributor with a centrifugal spark advance that was frozen; this caused severe overheating at high RPMs. A loose or cracked manifold can cause strange problems, especially if the intake and exhaust are leaking through to each other (some older tractors have a one-piece intake/exhaut manifold).

 

[rlk]

Thanks to everyone for your replies.

The latest is this:

Before running it Friday, I installed a clear plastic filter on the gas line. I wanted to be able to see if fuel was flowing to the carburetor when it cut off.

Ran the tractor for 3+ hours Friday. Had the gas cap just resting on the tank, not tight at all. After about 2.5 hours, it sputtered a few times, but did not cut off. After another half hour, it sputtered and did cut off. Since the gas cap was just sitting on the tank, there was no pressure or vacuum.

When it cut off, there was barely any fuel in the filter at all. Prior to this, the filter had been about half full.

This tells me that there is something in the gas tank that is blocking the flow. It only seems to do it after several hours of running, so I'm guessing when the fuel gets low, something in the tank blocks the connection to the gas line.

Usually I pour 5 gallons of gas in prior to running the tractor. 5 gallons brings it to about half full. I might try filling the tank all the way up to see if runs longer before cutting off. If it does, that definitely tells me something is in the tank blocking the flow of fuel when the fuel level gets low.

Following this test, guess I'll have to pull the tank to clean it and get it lined. I hate to do this, because the bolts holding the tank are not that easy to get to, plus you have to take the hood off, take the sediment bowl off, drain the tank, etc. As slow as I am, this will probably take a whole day.

Anyway, thanks to all of you, I'm slowly making progress determining what the problem is.

 

[Rubintropfen]

Take this with a grain of salt. None of it means you're not right.

I've heard that the clear plastic fuel filters might require more pressure than is present in a gravity feed system. Once the fuel in the tank gets low the pressure drops even further. It also bugs me that the amount of air in the fuel line would increase after the sediment bowl filled with gas (a good carburetor shouldn't leak air back into the fuel line, although maybe bets are off once it is starving for gas).

Could you try disconnecting the fuel line at the sediment bowl when it stalls out and prove that the fuel flow is restricted before that point?

You can probably check the screen in the bottom of the tank without removing the tank. Try draining the tank and removing the screen (and valve?) assembly. It works on an old Ford, but could be different on your MF. If the screen isn't really gunked up then I wouldn't worry about the tank. I would definitely try this before taking off the hood and removing the tank.

 

[Hydraman]

I had a clear plastic filter in my '79 low rider for years- strictly gravity feed- no problems. Also had them in garden tractors- gravity feed- no problems.

 

[djradz]

Before you pull the tank try this. Run it until it quits, then pull the hose coming from the tank to the filter and see it you get much flow from the tank. It could be that there's a filter in the tank that gets cleaned when you add fuel or the tractor sits, but over the period of an hour or two of running, junk, sludge, etc, collects around it. We had a boat fuel tank that did this. We would take the tank, throw some nuts and washers in it to act as scrubbers, and then shake the tank vigorously and work the nuts/washers especially around on the sides and bottom. Then pour them out and rinse the tank a couple of times with clean fuel.

 

[Rubintropfen]

Apparently the MF35 had a fuel shutoff valve with two inlets, similar to the Ford N-series. Opening the valve part way would only draw from the upper inlet, leaving some gas for transport in case you ran out. Opening the valve all the way would allow the lower inlet to operate.

If your valve is not open all the way, or if the lower inlet was plugged, then this would explain why you run out of gas with fuel visible in the tank.

<A target="_blank" HREF=http://www.ytmag.com/ferg/messages/12863.html>MF35 Fuel Tank Discussion on YTMAG</A>

 

[rlk]

Thanks to all who keep giving me more ideas.

I drained the tank again, this time letting it drain through the sediment bowl and the new filter I installed. The sediment bowl collected quite a bit of rust particles, some about as large as the head on a medium size nail.

Next I removed the sediment bowl and flushed the tank with gasoline. Collected a few more rust particles. Kept doing this until I did not get any more rust.

Reassembled everything and ran it for about an hour without it stopping. Would have continued running it but it got dark. It is misting rain today (thank goodness), so won't be able to give it a good test until later this week.

I've got my fingers, toes, and legs crossed hoping this resolves the problem.

Again, many thanks to all who have given suggestions.

Bob