Clean or replace injectors?

[California]

After a year running near 100% biodiesel I think I have carboned up the injectors. Cranking speed is ok (and I've cleaned all the battery cables etc) but the first start of the morning just pushes raw fuel vapor out the exhaust, running (barely) on both cylinders, but not strong enough to exceed the starter's speed. I thought it was a cold weather issue and used the thermostart, and even a hair dryer, to give it warm air and get it running, but the problem remains now the weather is warm.

The local diesel shop said he sees a lot of crudded up injectors due to biodiesel. It seems to correspond to biodiesel ageing faster than petro diesel. He said he now asks about the fuel and when it was biodiesel, especially in an engine that gets intermittent use, he finds that he has to soak injectors in carb cleaner for a long time to free them up before working on them.

What is the normal useful life of injectors before they need cleaning? I know nothing has been done on this engine in the 6+ years I've owned it and I think it was parked for years in the second decade of its life. The Operation manual just says 'see your dealer'. What does the dealer do? Is it possible to disassemble and clean injectors myself?

I wonder if it would be better to simply put in new injectors, compared to rebuilding units that have probably been in use 30 years, since new isn't much more expensive than professionally rebuilt.

Has anyone had to do this?

 

[ninefinger]

I remember when you started this experiment with bio. I thought your weather would not be a factor. We use bio at work and it seems there is more maintainance on the fuel systems than before. I was buying from a chain here that used to have the real stuff and then they switched to bio and I did not notice until the powerstroke would not crank in cool weather without plugging up the block heater. The 2210BD does not like bio either. Price is no longer an issue, I buy petro diesel only for both units. the tractor is happier and the glow plugs on the truck seems to be getting better. I would try to clean the injectors and then go back to straight petro diesel and give it 2 or 3 tanks and then make a decision. I traveled to California some years ago and they were real proud of their fuel so I can feel your pain.

 

[jerrybob]

I am far from an injector expert......so you're on your own there. As for the biodiesel.........that grease and stuff they put in there isn't good for your arterties.....why is anyone surprised it gums up your engine parts? In my part of the country.....biodiesel also costs a lot more........I never use the stuff unless I am making french fries......would never put it in my diesel. :confused2:

 

[normde2001]

After a year running near 100% biodiesel I think I have carboned up the injectors. Cranking speed is ok (and I've cleaned all the battery cables etc) but the first start of the morning just pushes raw fuel vapor out the exhaust, running (barely) on both cylinders, but not strong enough to exceed the starter's speed. I thought it was a cold weather issue and used the thermostart, and even a hair dryer, to give it warm air and get it running, but the problem remains now the weather is warm.

The local diesel shop said he sees a lot of crudded up injectors due to biodiesel. It seems to correspond to biodiesel ageing faster than petro diesel. He said he now asks about the fuel and when it was biodiesel, especially in an engine that gets intermittent use, he finds that he has to soak injectors in carb cleaner for a long time to free them up before working on them.

What is the normal useful life of injectors before they need cleaning? I know nothing has been done on this engine in the 6+ years I've owned it and I think it was parked for years in the second decade of its life. The Operation manual just says 'see your dealer'. What does the dealer do? Is it possible to disassemble and clean injectors myself?

I wonder if it would be better to simply put in new injectors, compared to rebuilding units that have probably been in use 30 years, since new isn't much more expensive than professionally rebuilt.

Has anyone had to do this?

Got any of that POWER SERVICE left over from 2004? Actually "blowing raw diesel fumes out the exhaust" sounds more like unburned fuel than an injector problem; however, I would at least try an injector cleaner before going too far. Then you might try firing up with exhaust manifold off and see if one, (or which), cylinder is not firing.

 

[runningbird]

I'll agree with normde2001 on this one. quite a few times when I got tractors from Japan and got them out of the container they would run bad. a little bit of a good fuel conditioner and 20 minutes at about 1800 rpm and they would be running like new...it is sure worth a try!

 

[California]

Got any of that POWER SERVICE left over... you might try firing up with exhaust manifold off and see if one, (or which), cylinder is not firing.

Power Service works great. I've used it since I bought the tractor in 2003. It runs noticeably smoother, reducing the deafening 'clank' these twins are famous for. I think what is happening is Japan has higher-Cetane diesel than the US and adding PS brings the Cetane level up to what the engine was designed for.

It's firing on both cylinders. I can hear the second cylinder catch, a couple of revolutions after the first one, and the cranking rpm increases, but not enough to run away from the starter motor's speed. A cold start needs several Thermostart/crank cycles before it will run away from the starter. (I verified the Thermostart works properly.)

I'll agree with normde2001 on this one. quite a few times when I got tractors from Japan and got them out of the container they would run bad. a little bit of a good fuel conditioner and 20 minutes at about 1800 rpm and they would be running like new...it is sure worth a try!

BTDT with this one!

I bought this tractor from a frustrated short-term second owner. He had burned out the Thermostart, burned up and replaced the starter (and battery), hotwired across the clutch safety switch, and replaced all the filters, trying to restore this unit after it apparently had been parked for years. What he didn't do was put fresh fuel in it. The exhaust burned my eyes so bad, and stunk so bad, that I'm pretty sure it was pre 1994 high sulfur diesel. This seller had bought an old near-abandoned farm, and I suspect there was nasty old diesel remaining in the farm's onsite tank so he fueled it with that. Or maybe it really had only used a half tank of fuel since 1994.

After I flushed the tank and doped it with PS (and replaced the flaky ignition and clutch safety switches, and replaced the dead Thermostart) this was suddenly a new tractor. (Well except for the appearance but we won't get into that! ) So I'm hopeful that PS will help.

After reading everybody's replies I decided to wait a little and see if PS will clean it up once again. I'm not hearing anybody say what I expected might be the replies here, that tearing down the injectors is customary maintenance. I looked in the manual and 'check the injectors - see your dealer' is in the 600 hour chart, so I expected to hear that everybody does that. But apparently its seldom needed.

 

[normde2001]

"and the cranking rpm increases, but not enough to run away from the starter motor's speed. A cold start needs several Thermostart/crank cycles before it will run away from the starter. "

What does that mean? Are you saying that, normally, when it starts you have to keep the starter engaged to keep it going? It should start at full throttle, release the key instantly, just like your car, then idle back the throttle.

 

[6thgpSF]

I had a bad injector that was dumping too much fuel and bent a valve,so I had all three rebuilt with no problems so far. russ

 

[California]

It should start at full throttle, release the key instantly, just like your car, then idle back the throttle.

It started easily that way for several years, up until this crudded-injector problem.

Then it started firing weakly after a couple of compression strokes. Eventually, recently, too weakly to out-rev the starter.

I have tried all throttle settings. Normally 7/8 throttle then instantly back down.

It's getting plenty of fuel. One observation: Before this got so bad, pulling it back to to 1/8 throttle while cranking would lean it out to a better air/fuel ratio and it would accelerate easily up to running speed from there, even though it couldn't accelerate with the throttle at 100%. It seemed to be flooded with poorly vaporized or non volatile fuel. The huge fog of exhaust while cranking is consistent with this theory of sufficient but non-volatile fuel.

I'm in for lunch at the moment after running the backhoe a couple of hours. It started easier this morning. This makes me wonder if the fresh diesel plus PS that's in there now after I flushed the fuel system is already dissolving crud. But it still doesn't start easy enough that I feel comfortable parking it overnight away from auxiliary power, just in case. This morning it almost ran in two attempts of Thermostart/crank. It lasted maybe twenty smoky strokes after I let go of the starter but couldn't gain any rpm.

I gave up and jumped it from the 24 a.h. HF jump-start battery. (Highly recommended!) This gave it the slight extra omph it needed, a hardly noticeable increase in cranking rpm but it fired right off properly after a couple of seconds. (Air temperature 55, a couple of hours after a low in the low 40's). After each day's first start it runs fine all day, and starts instantly so long as the block isn't cold to the touch.

Russ, now that's one vote for pulling and testing the injectors. Overfueling? Hmmm.

 

[California]

I put in new, genuine Yanmar, injectors this weekend. That solved the problem. Now it starts easily.

The manual says to service the injectors every 600 hours. These obviously hadn't come out for at least the past 20 of the tractor's 30 years. They are recessed about 1.5 inches into the head in a bore maybe .010" larger than the injector body, and one was rusted in so badly that it was a heavy press fit all the way out. I had applied penetrating oil (PB Blaster) two weeks, one week, then the night before the project so I suppose that helped some.

With the new injectors it not only starts easy, it runs nicer than before. Now the exhaust is distinguishable as a separate sound, and putting a gloved hand over the exhaust leaves more of a purr than before. I might even buy it a new muffler! It also will idle lower, smoothly, down below 500 rpm, with some clanking but not the unbearable 'about to grenade' racket like before, and it seems to resist clanking better now. I probably should have had the injectors gone through when I bought it in 2003.

I took a couple of photos that I'll put in a new thread in a day or so when I have time. Thanks everybody for your encouragement!