Slight OT... Diesel tractortroubleshooting question

Mike C. · Sep 14, 2014

Looking at an older (70s) JD tractor with 3 cyl diesel to buy for around the house and for bush hogging. Engine runs a little rough. Starts instantly and no white or light gray smoke at all, even cold, so I think compression is good. Put a hand over the exhaust and it's not sucking back, so I don't think it's a burnt or bent exhaust valve. No heavy black smoke, so I don't think it's a sticking intake. Thing seems to run great, just doesn't sound right.

My thoughts are maybe valve adjustment? Guy selling it says may be a bad injector or maybe a pump. Any other suggestions? Can get it reasonable enough to rebuild the engine and still come out OK, but I'd rather not.

JohnEvans · Sep 14, 2014

A 3 holer that doesn't run smooth ? Seriously how old is the fuel ,any inprovement at operating temp? Fresh fuel ,change the fuel filters and give it a dose of something like a qt of ATF in 3-4 gallons of fuel. ATF works real good for cleaning pumps and injectors.

abarnsley · Sep 14, 2014

Fuel Filter clean???

Injector partially gummed up?

Heavey Metal · Sep 14, 2014

3 cyl has a funny sound to it when right.

Check the heat at each exhaust port

Ir gun , hand , drop of water etc.

Those things are famous for the weight retainer spring failing (in the injector pump)

Mike C. · Sep 14, 2014

Heavey, I read up on the weight retainer, already. Thinking that may well be the root problem. Good news is that nobody has screamed "RUN AWAY!!!" yet, which is what I was checking for, lol. Guy at work used to rebuild injector pumps, so as long as it is not a totally ruined pump, that would be a cheap fix ($50 for a kit and a hamburger).

Fuel didn't smell rotten, but no idea how long it sat before this guy got it. Said it was a spare tractor a guy just used pulling a hay rake. Guy bought another big tractor from him and traded this one, as it would have then been the spare spare tractor. It probably sat except four or five days every four to six months. It's got a new Baldwin fuel filter on the side, so I figure he tried the easy stuff already.

Didn't even think to check exhaust port temps... duh. Should have known that from my old four cyl motorcycle days.

kenh · Sep 14, 2014

Sounds if the problem is minor,. If it took much cranking with gobs of smoke then a cause for concern.
Maybe a good work out would make it well.
I have a 3 cyl. Mitsubishi, some interesting sound effects, it smooths out around 2K RPM

If the price is right as you say I would jump on it.

BridgeportinD2 · Sep 14, 2014

Mike, I'd say your thinking of setting the overhead is a very good idea. That gets overlooked so often by so many. It's so easy to do, and helps with power and fuel economy. I'd be doing it regardless of whether it sounded right or not.

If it seems to be running fine, no smoke out of the norm, then I'd say you can eliminate a fuel inlet restriction, filter, transfer pump. I would tend to turn my attention to pump timing (static) and the advance mechanism.

That Deere would have a Series 300 Dubuque engine in it, which would have used Roosa Master 9mm pencil nozzles, which are cheap to replace. You may want to pull them and have them pop tested (leak down as well). If they don't pop at very nearly the same pressure, that will cause some uneven firing.

It's been long enough now since I worked on those tractors I can't remember which pump they'd have, but I'm thinking it's the Lucas CAV, not the Roosa Master/Stanadyne.

If you don't find the problem in the smaller things, and before you decide to pull the pump, let me know and I'll dig in some of my service manuals and find some easy things to check on the pump.

Sauerkraut · Sep 14, 2014

Put 2 qts. of power service or howes fuel conditioner in it with 5 gal. fresh fuel hook it up to a plow
and run it pulling hard for a couple hours.. That will clean it out.. It should run like a Swiss Watch after that!!

Good Luck

tdmidget · Sep 14, 2014

JohnEvans said:
A 3 holer that doesn't run smooth ? Seriously how old is the fuel ,any inprovement at operating temp? Fresh fuel ,change the fuel filters and give it a dose of something like a qt of ATF in 3-4 gallons of fuel. ATF works real good for cleaning pumps and injectors.

Yeah, hydraulic oil with red dye in it is a magical substance :nutter:

Limy Sami · Sep 14, 2014

Mike - Like the man said 3 cyls have an off beat note.

This one ain't the sweetest but it might help John Deere 830 3 cylinder tractor complete running diesel engine - YouTube

From a former life, JD pencil injectors are great until they're not, with it running, try slacking each injection pipe off in turn - if they all make the same difference, it's probably not them

Mike C. · Sep 14, 2014

Thanks guys! I guess I am going to pull the trigger on the deal this week. It is definitely rougher than the one in the youtube vid, but that did help. I just didn't want to spend money on something that was going to instantly require $3000 worth of work (although I would still probably be able to about break even if I cleaned it up turned around and sold it). Needless to say, it's not real pretty, and I'll have some things to fix up on it, but that's just how it goes with anything used.

I think I'll start with Limy's check of the injectors to see if it has one or more weak ones, then do valve adjustment, then have a look at the injector pump if it persists. Hopefully won't be any more serious than that.

true temper · Sep 15, 2014

If the weight retainer is bad the tractor will quit running. The plastic from the retainer plugs up the check valve in the top cover of the pump. There is a fitting in the top of the pump that has a glass check ball in it. If it has black plastic rubber stuff in it that's the retainer coming apart. The tractor will not run with the return check valve plugged up. In an emergency you can knock the ball out of the fitting and clean out the trash and finish the job.

3 cylinder motors just don't sound right. You don't have to worry about "running away" on a JD, Deetroyts had that problem.

Mike C. · Sep 15, 2014

Thanks, again. Talked to the guy at work that used to work at a diesel shop building pumps. I told him what kind of tractor and what it was doing. Before I could even start on various suggestions, he said, "retainer ring on the governor in the injector pump is shot." Apparently when it goes, it may or may not plug the check valve, but it starts letting the governor basically chatter, which causes a weird missing effect, but the engine otherwise runs perfectly. he said he'd give it a 99% chance that was the issue. Said it was too deep in there to just pop it apart and replace just that, so it'll mean a pump rebuild or new pump. Have to see if the seller will come off a little.

Mud · Sep 15, 2014

I have a '77 302A we bought new, 3 cyl. In the 80s it had a pump problem, ran real rough and knocked, finally would shut off and not restart until cold again. Dealer said it was a chronic problem with the pumps, there was a bakelite part inside that failed, we rebuilt the pump and it's been fine since. I was told that if it shuts off, you can crack the screws holding the cover plate on the side and let it leak fuel while it's running in order to get it running long enough to move it out of the way.

I remember that last part distinctly because it finally quit halfway out an open garage door during a snowstorm

I don't think mine has an odd sound at all, maybe I'm just used to it.

Mike C. · Sep 15, 2014

Yup, I think it's going to end up being that plastic governor weight retainer. Just have to see if the guy will come off the price a little to help me out.

Rob F. · Sep 15, 2014

Mike C. said:
Guy at work used to rebuild injector pumps, so as long as it is not a totally ruined pump, that would be a cheap fix ($50 for a kit and a hamburger).

Mike C. said:
Yup, I think it's going to end up being that plastic governor weight retainer. Just have to see if the guy will come off the price a little to help me out.

I'm all for getting the price down but don't beat the guy up so much he tells you to get lost. Sounds like a good deal already.
Rob

Mike C. · Sep 16, 2014

Picking it up Sat. He didn't want to come off the price much, so I conceded rather than let it get away. Details when it's here. Thanks much to the knowledge here.

smoking-swarf · Sep 17, 2014

Possibly slap in the timing chain or gears, some of our tractors do that when the load comes off them. Just a thought.

kuraki556 · Sep 18, 2014

I have a Deere with a 3 cylinder Yanmar diesel. Whenever it's running rough, it's because it's gotten air into the fuel lines some how and they need to be bled. On my tractor, there are bleeder screws at the fuel filter/water separator, at the T fitting where fuel enters the injection pump, and then the compression fittings used to attach the fuel lines to the injectors are used to bleed as well. Air can enter when the fuel pickup comes above the level of fuel in the tank (low fuel on an incline) as well as from poor seals in the high pressure system.

I don't know what tractor you're looking at or what engine, but the other thing I've learned is that Deere did not let Yanmar sell service parts, so everything comes from them for my engine, which is generally not cheap.

I love the tractor and am in the market for another one, preferably a 4x4 655/755/855 but they're not all sunshine and roses. I'm currently waiting on a quote from my local engine machine shop on rebuilding my diesel, since it's blown a head gasket and I blew the new replacement one in only 3 hours of service (after having the head checked, resurfaced and rebuilt.)

I would spend some time on JD parts website making sure stuff is available for the model prior to pulling the trigger, myself.

Also, all the 3 cylinders I've seen run rough at low RPM. They really don't seem happy until about 1000-1200 RPM, and when mine is down at 600 you'd think it was going to jump right out of the tractor.

Mike C. · Sep 18, 2014

"I don't know what tractor you're looking at or what engine, but the other thing I've learned is that Deere did not let Yanmar sell service parts, so everything comes from them for my engine, which is generally not cheap."

That's why I wanted an older tractor. It is a 1970s 301A with a genuine Deere 3cyl, not a Yanmar. As I said, more details pics and info to follow Sat.

Slight OT... Diesel tractortroubleshooting question

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