YM240 smokes heavily, lacks power

[winston1]

.006" on the valves, 127 -133 is foot lbs. 14-15 ft lbs on the injector hold down bolts. I like Gary's idea about the fuel filter. Won't it be lovely if it can be that simple?

 

[6thgpSF]

you might try checking that 0 ring on the fuel filter while your looking at it. good luck russ

 

[284 International]

Another mission accomplished! After draining and exchanging the fuel again, resetting the fuel filter and bowl twice and the subsequent bleeding, I decided to check out the top end of the motor. When I pulled the valve cover, the trouble was immediately obvious. An intake valve rocker had come off the rocker shaft, and the pushrod had fallen into the block.

Naturally, the inoperable valve kept the cylinder from burning the fuel until it was expelled into the air. After truing the slightly bent pushrod and reassembling the pushrod and rocker, I checked the valve clearances, re-torqued everything and it fired right up! Minimal smoke at startup, and it runs normally. It seems to be a bit down on power, and doesn't really want to lug the way I would expect a 2 cylinder diesel to do, but it isn't running poorly, and it doesn't have the smudge pot effect going on anymore.

Thank you to all who have helped me with this issue. I'm going to run it awhile and get it nice and hot working around the yard, then re-check all the valves and torque specs. The assistance is really appreciated. I've noticed that the turf tires have extremely poor traction trying to pull the disk. I'm going to have to work on correcting that with different tires.

 

[Gary Sweat]

Another mission accomplished! After draining and exchanging the fuel again, resetting the fuel filter and bowl twice and the subsequent bleeding, I decided to check out the top end of the motor. When I pulled the valve cover, the trouble was immediately obvious. An intake valve rocker had come off the rocker shaft, and the pushrod had fallen into the block.

Naturally, the inoperable valve kept the cylinder from burning the fuel until it was expelled into the air. After truing the slightly bent pushrod and reassembling the pushrod and rocker, I checked the valve clearances, re-torqued everything and it fired right up! Minimal smoke at startup, and it runs normally. It seems to be a bit down on power, and doesn't really want to lug the way I would expect a 2 cylinder diesel to do, but it isn't running poorly, and it doesn't have the smudge pot effect going on anymore.

Thank you to all who have helped me with this issue. I'm going to run it awhile and get it nice and hot working around the yard, then re-check all the valves and torque specs. The assistance is really appreciated. I've noticed that the turf tires have extremely poor traction trying to pull the disk. I'm going to have to work on correcting that with different tires.

Glad to hear you found the problem. It will probably clean up after running for a while and start pulling like it should.

 

[winston1]

Another success story. :thumbsup: I notice from your profile you are a teacher. Thank you 284. Both my kids started out as teachers, my son has since got out but I have a high regard for you folks that are in that profession.

 

[clemsonfor]

NOt having been in my yanmar that deep or any deisel for that matter, im not totally familiar with this. But did the valve not hammer and dent away at the top of that piston from all that running it before. Also if the valve is not striaght wont any valve stem seals not seal it tight to keep oil , etc from entering the cyl?

 

[284 International]

Thank you, Winston1. I really enjoy teaching, though in my sector the pay is on the low side of things. That's my decision, though, and it isn't a complaint, merely an observation. It also comes with rewards unlike other fields, too.

I'm excited and grateful about putting this lime green, clattering machine to work. I had my little 1401D over at fellow church-goer's house today, they had about 4 1/2 feet of mud come through their yard and INTO the house late Saturday night. Inside the home there is mud and water up to the doorknobs. It made my frustrations over not getting the tractor running seem insignificant. After checking things out on it again today I'm going to drive it over and drop it off for them to use while working on getting their home clear of muck.

Thanks to all here who have assisted me, I hadn't planned or known it was going to be put to work for such an important or worthy cause, but it has really been a blessing. I'm worried about the turf tires complete lack of traction in mud, so I'm going to check the bolt pattern and backspacing on the ag tires from my 284 and see if I can swap them over. Thanks again to all, it ended up being advice that will change people's lives.

 

[284 International]

Clemson, on my engine the rocker arm is mounted on a shaft holding an intake rocker and an exhaust rocker, very similar to how small block Chryslers are set up. When the pushrod fell out of its socket on the rocker, the valve could not move, so there can't be any damage to the piston or the valve by contacting each other, since the valve wasn't being actuated.

If the valve had been bent, the seals might be a problem. In this case, the pushrod was slightly bent, not the valve. There are no pushrod guides on my engine, the pushrod sits captive between the lifter and a pocket on the rocker arm. I suspect it got slightly off-kilter when it came loose, and got tweaked a little.

I straightened it until there is no visual runout on my motorcycle wheel balancer, as well as spin testing it like you would an arrow and rolling on a flat piece of mirror. It's not the correct way to do things, but for now, and until a new pushrod arrives, it will work.

California, I hope my last comment isn't foreshadowingly ironic, given my recent gripe about people doing field expedient fixes and never properly doing the service and repairs equipment requires!

 

[careyo63]

After finding valve train damage like that a compression check was due. I would have preformed it as soon as you was able to reasembled the valve. It also may have damaged the Tappet . Then if you are still having problems you can rule out 1 of the 4 must haves on a diesel eng. Fuel, air, compression and Exhaust. The other are useally easy problems to take care of fuel, air and Exhaust. Courious which Rod Was bent Exh. or Int?

Carey

 

[clemsonfor]

Ok when i read it i somehow, I read that the rocker arm came loose and thuse somehow your valve was loose and dropped into the cyl!! I was wondering how you got it out and how all that was done was bend the shaft?