YM240 smokes heavily, lacks power

[284 International]

Resolution! When I last parked the tractor, I shut it down normally with the fuel cutoff position on the throttle. When I restarted it, I got the same symptoms as I had earlier! Knowing what to do, I pulled the valve cover, and discovered that this time, the number one cylinder's rocker arm had come off its shaft:

I set it all back together, and decided to move around all of the other paraphernalia that came along with the tractor. There was a disk harrow,
and then a 3 point mount that looked to be adaptable to a cultivator, or small planters, or weight bars.

In a grocery bag wrapped around the offset disk, I found the retainers for the rocker arms! There were some clips and pins too, along with what I suspect is the radiator brace. I hadn't thought there might be engine parts in there too; they had been out in the rain for awhile. I cleaned up the retainers with a wire brush and some naval jelly, wiped them down with WD40 and paper towels, and got set to put them on:

Note that this is NOT where they are supposed to go! They go underneath those nuts. What are the torque specifications for those nuts fastening down the retainers? I'm at a standstill until I fasten them down completely. I hope to get this all back together correctly so it can last another 30 years, so want to do it right the first time.


All I need now is to run some return lines from the injectors to the tank (the return lines don't discharge any fuel, is that normal?), change the oil and filters, and the motor will be ready to go. The chassis, however, may be another matter. Find my new thread about fixing major safety hazards here: YM240 spindle and steering repair - TractorByNet.com

Thanks to all who assisted me with diagnosing and fixing this problem, I really appreciate it.

 

[bowinelk]

Torque spec. on the rocker arm assembly nut is 58-72 ft lbs. Just a note when you torque them back on. I used a large cresent wrench to hold the retainer clips from twisting with the nut as I torqued. They wanted to twist and bend if not held in place.

It looks as though your radiator shroud is missing. which helps funnel the air through the core. As far as the mounting of the radiator. There are only 3 pts of contact to hold it place other than the hoses themselves. 2 studs in the bottom, which it sets on 2 rubber mounts, and the bracket you mounted onto the head.
I suggest if you do pull the radiator again. Take it in and have it flow tested. If you have some restricted areas this could be contributing to your over heating. If the core is good they maybe able to rod it out for less than buying a new one.

As far as the return lines on the top of the injectors. I don't think much fuel if any goes through there. But i too am curious how that works.


My partner is tired of working on the tractor too. But he stays with me any way.

 

[284 International]

Thanks for the numbers, bowinelk. I have a really big crescent that I'll use exactly as you say. I started to see that coming as I tightened the nuts, so decided to check on correct specs and procedures.

The bottom of the radiator is fastened in ok, and everything is alright there. The battery in the front tray is oversized, though, and the electric fan on the front of the radiator sticks out and puts pressure on the radiator to tip backward when it bounces. I don't have a shroud in my parts box. I'm conflicted about what to do. I'm sure the electric fan will keep it cool enough, assuming the radiator is good. A new, correct sized battery or a revision of the mounting tray will let the battery sit and not bump into the electric fan. A hold down bracket will be a lot better than the bungee cord it now has.

The previous owner said he could work an hour or two before the overflow tank started to bubble, and that was with a blown head gasket. I used good quality anti freeze with distilled water and some Water-Wetter to make about a 35% coolant to 65% water mixture, which should offer me sufficient freezing protection and much better heat transfer. I don't anticipate any cooling issues now; I'll see what happens come summer time.

If it ever gets hot, I'll get the radiator rodded out and order or make a shroud. A new fan blade may be in order, too. Thanks again for the help.

I really like your boxer, that's a good looking dog! He looks content on his bed, that's for sure. It's nice to have a buddy like that around.

 

[winston1]

The little thermostart bottle is designed to be kept full by the leakage by the injector stems. My 2002d does exactly that, however, I have read of many that didn't feel they were getting anything out of there either. I seldom use mine so use very little out of it. Not enough that passes through it that you can see it drip back into the fuel tank. I would suggest hand filling it the first time and then just keep an eye on it.

 

[careyo63]

It was in the low 30's last week so I was able to check my TS setup out. Works great and Cheap!!! Parts from the Junk Box.
Winston on my Alt. Belt I was able to get a better look and found the Logo. MITSUBA. Google came up Thailand.

Carey

 

[normde2001]

Why not keep the large battery, fix the heating problem, and get rid of the electric fan.

 

[Gary Sweat]

My TS bottle finally filled up after a couple of days of running the engine around 1800 to 2000 rpm. Appears it will produce some fuel in the return line at higher rpms and then only a little. Now the bottle stays full all the time.

I would get that fan replaced as soon as you can or remove it. If a piece breaks off it could cut a gouge in the radiator.

 

[284 International]

Winston, thanks for the feedback on the Thermostart. I've never needed or used it. It's not currently wired, so I need to make sure the heating element works. I didn't know how much fuel was supposed to come out of the return, and didn't want to have them unattached if/when they started spraying fuel as I tinker. I'll get them connected and investigate the Thermostart.


Norm, I think the overheating troubles will be fixed by the head gasket repair. I like the larger battery, but it's too big to sit in the tray, and it has to tilt one way or the other. I think a slightly smaller battery would fit correctly or at least close enough to not give me interference trouble. It would also save me from having to hack off the battery tray and build a new one. The tractor will be out of commission while I repair the front end components, so if I can't find a shroud to order I'll have to keep the electric fan.

Gary, I need to replace the fan. It would probably be fine, the plastic isn't brittle, but the expense of a new radiator versus a fan blade doesn't make the risk reasonable.

Thanks for the help.

 

[bowinelk]

On my 240 the injector over flow goes straight to the fuel tank. My thermostart has a small reservoir, that I have to manually fill.

 

[winston1]

On my 240 the injector over flow goes straight to the fuel tank. My thermostart has a small reservoir, that I have to manually fill.

Two options, acturally three counting Carey's bulb, here's a couple. If you click on "this tank" you see the second. Yanmar Tractor Parts: THERMOSTART TANK_