L225 started knocking on hillside

[08k8]

It is and has been pretty cold here for the past several weeks and I've been getting into my hilly woods to haul our firewood. I had a nice Oak that fell and I wanted to get it out. The slope is pretty steep and I backed the tractor down the hill to drag out logs. I made 6 successful pulls without any issues. Chaining up the 7th section of log, the engine started knocking as it idled. I shut it off right away.

Figuring that I didn't want the tractor stuck down in the woods, I unhooked the log and drove the tractor back to the shed.

My initial fear / thought is that I maybe starved the engine of oil and threw a rod... I've seen a few posts on this site suggesting that it might be air in the fuel?

What is the order of attack here?
Bleed Fuel system
Check injector spray pattern

Pull oil pan and look at crank end of rod.

IF the crank isn't damaged, just change rod bearings?

 

[kuboman]

A stuck injector will hammer like a a loose con rod. Does it still knock on the level and after it has sat?
You can check injectors by loosening each injector line one at a time to see if they all cause a rpm drop.

 

[D2Cat]

Install a temporary mechanical oil pressure gauge (where the sending unit is on the side of the engine) to determine oil pressure.

 

[rbargeron]

What is the fuel level in the tank? In my experience as the level gets low, water droplets in the bottom of the tank move toward the pickup and may get into an injector. Water can cause a Kubota engine to develop a very ominous knock. I'd suggest draining the tank, and filling with clean fuel (check your fuel can for water contamination). My L48 did it once, sounded very bad. Clean tank and new fuel cured it Good luck, Dick B

 

[08k8]

So- I haven't started it up yet- mainly wanting to get feedback before doing so.

The fuel is fresh and about 1/4 to 1/3 full. I have a sight tube on the tank and I haven't seen any air in it yet. Before starting work, I put 2 fresh gallons in. I do heed your warnings though about water in fuel and will check. Best advice is to drain and replace with fresh, I assume.

I will grab some fresh fuel after work tomorrow and report back.

 

[08k8]

So, been out in the shed all night....

Before starting, I pulled the oil filter and cut it open with a pair of snips. I was happy not to find any nasty metal or proof of eating a rod bearing.

I fired the tractor up and it didn't knock for the first 3-5 seconds then, the knock was back. I had the block heater running for ~2h before starting and it's about 35F out right now. I went ahead and bled all 3 injectors. It sounds a heck of a lot better.

The front injector - nearest the radiator seems to have the biggest effect on the normal diesel rattle sound. That is- when I deactivate this cylinder, the engine is pretty quiet and almost doesn't sound like a normal diesel. The other 2 cylinders don't have nearly the same effect on diesel clanking. I'm not nearly as worried as when I started this thread - but I'm curious now why that front cylinder causes more noise than others.

I'm going to grade my road tomorrow to put a few hours on and see how things go.

 

[D2Cat]

Just as kuboman suggested, bad injector. If you're going to work the engine I'd put some injector cleaner in the fuel and maybe a miracle will happen. When it doesn't happen replace all the injectors with Kubota, not aftermarket, injectors. Might even be able to have them rebuilt.

 

[08k8]

Just as kuboman suggested, bad injector. If you're going to work the engine I'd put some injector cleaner in the fuel and maybe a miracle will happen. When it doesn't happen replace all the injectors with Kubota, not aftermarket, injectors. Might even be able to have them rebuilt.

I was looking at the aftermarket injectors, probably as you wrote this. Are they all junk? Looks like $45 - $60 on ebay

Looking @ the kubota parts diagram for the L225, it is a little unclear what is the PN for a complete injector

I attached the image from the parts company.
1.1 INJECTOR, FUEL A replaces #15221-53000 70000-65208 $69.44
1.1 INJECTR replaces #15221-53020 70000-65209 $67.50
2.1 INJECTR replaces #15221-53030 70000-65209 $67.50

 

[08k8]

Ran the tractor for 2.5 hours last night blading my rode. I loaded it up a fair bit and it seems to be running fine.

Thoughts on still replacing the injectors?

It has 1600h on it.

 

[rbargeron]

So on a scale of 1 to 10 how severe was the knock at the beginning, after purging the injectors, and now after working 2.5 hours?

 

[kuboman]

Get yourself a bottle of a real good fuel conditioner and dose your engine 3 time normal rate. I think you had a stuck injector which can be caused by a multitude of things. Dose the fuel and work it hard for as long as you can. I wouldn't be spending money on injectors yet.

 

[coachgeo]

after you dose the injectors good... maybe early in summer before she really gets put to work..... get three pie tins. Get some Carb cleaner. Not the spray stuff.... but the stuff that comes in half gallon or gallon can designed to be pumped thru a carb cleaner/part cleaner basket.

Remove injectors..... place in pie tin clearly marking which injector went where. Dissasemble the injector as much as you can. Pour the cleaner into the pie tin and let them soak for up to a week. Shake the pie tins at times......

Some say do this in as CLEAN area as you can.. especially before reassembly so you keep even super tiny junk out of them. Example some shops that do this professionally actually have a cleanroom....

While doing the injector soak; also soak all cylinders and sump in engine cleaner... some just use diesel and ATF. 50/50? Some Say Marvel Mystery Oil is best?? Same idea as injectors... let it sit. Hand turn over engine some.....at least three times. allowing a new cyclinder to be further down full of cleaner..... you want the stuff to sit on cylinder tops.

Then flush the heck out of it...... refill sump with cheap oil..... even cylinder tops..... let it all drain thru...

Then make sure cylinders are completely free of any liquid reasonably as you can...even crank her over to spit all stuff out injector and glow plug holes.

Then still using cheap oil fill in sump to normal levels...... reinsert injectors and Glow Plugs ...... bleed system and start her up with a good glow and good battery. (would be good time to replace glow plugs) she will smoke enough to kill all the summer mosquitoes..... when finally running sorta normal.... change oil again.. repeat few times.... maybe in these running's use some Seafoam.......

After final clean..... take out cheap oil and put in the good stuff.

Whala.. new engine........ for few years at least. Not like off show room floor and won't stay clean as long as a fresh engine rebuild would..... but will be much better off than she was before.

 

[08k8]

At the beginning, on the hill, it was a 10.0

After bleeding the injectors 2x, I'd say that I'd give it a 2.0

Running the old girl for a couple of hours, honestly it sounds pretty normal.

I guess what I'm after here is- should I just buck up and replace the injectors because of their age and wear? I don't log too many hours per year - but I depend on this tractor and would like to keep it for a long time to come.

 

[85Hokie]

I guess what I'm after here is- should I just buck up and replace the injectors because of their age and wear? I don't log too many hours per year - but I depend on this tractor and would like to keep it for a long time to come.

I would follow the advice of D2Cat and Koboman - flush the lines with good stuff first, IF YOU find that it still is not behaving as it should - follow Coach's advice - this way you will learn a lot about how the injector works and how meticulous these little injectors can be! AND IF somehow a injector is not "perfect" enough to place back in the tractor - you will order new injectors! Nothing lost here but time and energy.