Forum for air cooled diesel engines and clones

[jakemaxwell806]

Ah, OK - I think if you look at the last video I posted, you can see the "throttle / governor" bouncing, and hear the engine smooth out a bit if I hold it ~1/2 throttle. This would be the same motion I believe, right?

I watched the video try turning that screw in some until it smooths out like you was holding it that screw is your rpm limiter it could possibly be turning a few more rpms then it should be getting valve float the valve springs are weak in these engines 4000 is all I can turn my engine with out it starting to do that flutter with pulling I let it get under load then open on up some more to deliver note fuel

 

[xp190]

Looks and sounds like the issue I am having, flames shooting out of the exhaust causing everything to cook, as well as the rough running.
From what I found on mine, and what 90 said, it sounds like an electrical issue brought on by something else.
Either the oil filter is plugging up causing the low oil shutoff to kick on and off, or as I suspect in my case, the wiring to the fuel pump solenoid came loose resulting in a bad bouncy connection when the engine vibrates having the same effect. At least I hope that's all it is, once I put mine back together I will know for sure now that I know internally everything is fine.

90 question for you, you said to soak the piston in purple power to get the carbon off, I have an Canadian equivalent of purple power here called Zep Purple, it says it's bad for aluminum, I'm using Zep 550 formula instead which is supposed to be safe for aluminum, I will see how well it works in a few days.

xp

 

[OldRedTractors]

OldRedTractors


I read your previous posts and you mentioned you hadn't pulled the filter yet, that should be next step to determine if anything is going on inside.
My first silent generator looked exactly like yours but with a different name.
I was letting a friend use it during a huge ice storm several years ago when it failed at 40 hours or so. It kept shutting down due to low oil pressure and was skipping & popping like yours.
The problem was a failed cam bearing which plugged the filter causing the shut down.
I also repaired a Yanmar L70 mil surplus that had the same symptoms and that issue was corrosion on the injector lobe that caused the hardened cam surface to flake off which changed the injection event at full speed. The cause of this was wet stacking then prolonged sitting allowing moisture to corrode the cam.
Your symptoms are similar but you say the injector lobe is perfect. Did you rotate the engine to look at the entire cam?
If the cam is good and the filter is good I would look at the injection pump, possibly a restriction in the inlet of the pump.
The pump can be disassembled quite easily for inspection.
Prepare a clean area and remove the spring retainer and carefully remove plunger.
The fit is extremely precise so care in removing and reinstalling it must be exercised as it can get stuck, do not force!! Use Finesse!
There should be no surface defects.
Care in handling is essential as moisture on your hands can cause corrosion so handle carefully and use diesel to clean & lube during reassembly.
One other thing to look at are the valves, check valve clearance if ok turn engine over to TDC so valve won't fall into engine and and remove the valve springs to so you can check for a worn guide, very unlikely!
That's all I can think of for now.
90cummins

Thanks 90cummins! Here is what I've done today:

- pulled the oil filter, and it's fine. A few very tiny flakes visible after cleaning it, perhaps 5 to 10, but nothing I wouldn't expect from an engine with only 60 hours on it and one oil change after initial break-in, perhaps 50+ hours ago. Certainly not plugged nor anything alarming

- Yes, I looked at the fuel pump cam, turned the engine over, and it looked fine all the way around best I could see.

- I pulled the pump and disassembled - easy once I came up with a way to compress the spring Nothing to see there as far as I could tell. Everything looked brand-new, smooth, no wear marks or scoring, everything clean, and no obstructions in the feed to the plunger. The pump plunger can be reinstalled 180 off, which would make it not function, so thankfully I paid attention to that in reassembling it. Clever and simple mechanism actually... but nothing obviously wrong.

Next step is to pull the valve cover and see what's going on with the valves. Hard to believe anything seriously wrong, given how easy it starts, but I'll look to see if the clearances are too tight or something.

I can't see the fuel cut-off being the cause of this, but I could try running 12v directly to the solenoid valve to be sure.

I'm tempted to just junk the whole thing and bite the bullet and buy a Kubota, but now it's personal!

 

[OldRedTractors]

I watched the video try turning that screw in some until it smooths out like you was holding it that screw is your rpm limiter it could possibly be turning a few more rpms then it should be getting valve float the valve springs are weak in these engines 4000 is all I can turn my engine with out it starting to do that flutter with pulling I let it get under load then open on up some more to deliver note fuel

Well, perhaps, but I didn't change that, and it previously was running the right speed for the generator output (3600), so I'm hesitant to mess with it. Also, it's not running up against the governor stop, but oscillating back and forth at less than full throttle.

 

[xp190]

Hey OldRed, if you have a chance, try the 12V straight to the fuel cut-off and let me know if it makes any difference, because if it doesn't, I gotta keep looking, I got a replacement genset already, but with this one it is personal for me as well. There has to be a real cause for the flamethrower effect.

xp

 

[90cummins]

ORT said; I can't see the fuel cut-off being the cause of this, but I could try running 12v directly to the solenoid valve to be sure.

That statement jogged my memory!!
On the silent diesel generator I repaired it had several problems.
One of the problems was skipping like yours (after) I installed new rings and cut new valve seats in it.
I found that the power to the injection pump was erratic. I traced to problem to the remote start black box which was sensitive to vibration and position.
That part was not available so I had to make one.
Took me quite some time to build a circuit using relays that allowed me to retain the low oil pressure shutdown system.
As I recall I had to install a momentary push switch that would allow it to start & run until oil pressure activated the run solenoid.
Running power directly to the solenoid would be my next move!!
90cummins

 

[xp190]

I have that black box for remote starting, I guess I will be trying this as well.

xp

 

[OldRedTractors]

ORT said; I can't see the fuel cut-off being the cause of this, but I could try running 12v directly to the solenoid valve to be sure.

That statement jogged my memory!!
On the silent diesel generator I repaired it had several problems.
One of the problems was skipping like yours (after) I installed new rings and cut new valve seats in it.
I found that the power to the injection pump was erratic. I traced to problem to the remote start black box which was sensitive to vibration and position.
That part was not available so I had to make one.
Took me quite some time to build a circuit using relays that allowed me to retain the low oil pressure shutdown system.
As I recall I had to install a momentary push switch that would allow it to start & run until oil pressure activated the run solenoid.
Running power directly to the solenoid would be my next move!!
90cummins

Thanks - I'll give that a try. Didn't have time today, and unfortunately it's now going to be a week or so before I can get to re-installing the pump and giving it a go with the jumper wire.

 

[xp190]

I think I fond the issue with my 186f.

I finished taking everything apart, I got the cylinder done, new rings, everything checked for specs, no real issues found, until I started putting everything back together and took out the oil pump.
The outer ring was all broken up into pieces, which, when I thought about it explained what was going on.
I have not tested this, but here is my theory, please let me know if it makes any sense.
The outer oil ring pump broke up into pieces, but not in every spot, it broke up into three pieces leaving one of the pump chambers intact and all the others leaking the oil out, this resulted in an uneven pressure build up. For every chamber that was hit which was cracked, the oil would escape, but for the one that stayed intact, the oil moved as expected. So what we have is a very inefficient oil pump.
What this resulted in, is the oil sending unit fluctuation on and off as the oil pressure fell and raised back up once per every revolution of the oil pump. The oil sending unit caused the fuel solenoid to kick out just as often, which then resulted in the engine initiating a shutdown, and then restarting at a fairly high frequency, this is why the engine was missing.
In order to bring up the rpm after one such initiated shutdown, the fuel pump would dump more fuel into the cylinder, so a very rich mixture, but since on the next revolution it was probably shutting down again, a lot of the unburnt fuel would make it into the exhaust where it would burn up later causing the flame thrower effect.

Pretty simple reason for the failure, I've never seen one of these oil pumps fail, but that is the only thing I found wrong with the whole thing.
I'm curious to see what you guys think.
I will post a picture of the broken up oil pump soon so you all get a better idea of what I'm talking about.
New oil pump is on order.

xp

 

[OldRedTractors]

xp,

Interesting find! I'd suspect that would impact the oil pressure overall for sure, but I don't know if it would cause it to pulse. Given the speed the pump turns, it's hard to imagine the pressure fluctuating or dropping low enough quickly enough to cause the switch to detect it - I just wouldn't think a mechanical switch would be that sensitive. I would think it would be lower overall, but relatively constant on average. And I'm not sure what would cause oil pressure to to drop with increased RPMs with a failed pump like that.

I suppose that if the pump was cavitating or sucking air at higher speed, that could cause a pressure drop for sure. When I get back I'll bypass the fuel cut-off on mine and see if it changes anything. Your explanation of the behavior does make sense, but perhaps it's more electrical than oil pressure related.

Feels like a Sherlock and Holmes case!

 

[Kyle_in_Tex]

Good possibility. I will stay tuned to see if it fixes it.

Question, Can you buy OEM Yanmar parts to fix the bad parts in the Chinese engines?

I still have a Yanmar L100 hooked to a 28 volt DC genset I would like to sell. Perfect for off grid battery backup. I believe you would use it in a 24 volt system.

 

[90cummins]

Good possibility. I will stay tuned to see if it fixes it.

Question, Can you buy OEM Yanmar parts to fix the bad parts in the Chinese engines?
I still have a Yanmar L100 hooked to a 28 volt DC genset I would like to sell. Perfect for off grid battery backup. I believe you would use it in a 24 volt system.

What generator are you running with you L100??
I built a 24 volt unit for off-grid using a Niehoff N1603 450amp Mil surplus alternator.
I can pull 200 amps with the alternator turning 1600 rpm.

The chinese replacement parts are described as fitting real Yanmars so I would think that Yanmar parts would fit the china clones.
Can't say for sure but they would be a good upgrade.
90cummins

 

[Kyle_in_Tex]

Good possibility. I will stay tuned to see if it fixes it.

Question, Can you buy OEM Yanmar parts to fix the bad parts in the Chinese engines?
I still have a Yanmar L100 hooked to a 28 volt DC genset I would like to sell. Perfect for off grid battery backup. I believe you would use it in a 24 volt system.

What generator are you running with you L100??
I built a 24 volt unit for off-grid using a Niehoff N1603 450amp Mil surplus alternator.
I can pull 200 amps with the alternator turning 1600 rpm.

The chinese replacement parts are described as fitting real Yanmars so I would think that Yanmar parts would fit the china clones.
Can't say for sure but they would be a good upgrade.
90cummins

I can't tell what generator is attached, it is under an olive green protective shield. I would guess that it puts out about whatever 9 or 10 horsepower is capable of.

 

[California]

Question, Can you buy OEM Yanmar parts to fix the bad parts in the Chinese engines?
I still have a Yanmar L100 hooked to a 28 volt DC genset ...

Its worth a try but may not work.

When I bought my 1980 US-version YM240 in 2003 I found the local Deere dealer had sold them new, and still had an 'Authorized Yanmar Parts' listing in the phone book. Fine, I went to see him. The parts guy went nuts on me. He had had too many bad experiences ordering factory Yanmar parts for gray-market imported Japan-market Yanmars. Customers then returned many parts because seemingly identical tractors could be at different revision levels or something. The guy was just plain unpleasant. I've never gone back. Hoyetractor sells NAPA-quality replica parts mailorder and that's all I've ever needed. Also, I've been told nothing will be sold without providing the tractor's serial number. Maybe to identify revision level, or maybe to shut out the gray-market versions.

After some reading it seems Japanese marketing adheres to a strict model of dealers licensed to to sell only in their own exclusive region and parts only for models they are authorized to sell - just a cultural difference but I think that is binding on Yanmar Marine dealers worldwide and possibly tractors, and small engines.

Hopefully you will find the small-engine OEM market is friendlier than this.

 

[thepumpguysc]

Hoye Tractor.. is good.
another choice would be to search the marine side..
The marine version is the same as the non-marine version, except for the exhaust manifolds..
MOST of them are in sailboats.. & "sailboat people" are a different breed..

 

[90cummins]

Honda engines were one of the first engines that I'm aware of that the Chinese started cloning. My local small engine shop (good friend) uses Chinese parts quite often with good results for repairs not only with Honda engines but chain saws as well. He ordered a real Honda V-twin engine for a customer and found it a small tag (made in China) customer was not happy.
Seeing that the Yanmar diesels are another favorite that the Chinese like to clone I would put a little money on the table and say the OEM Yanmar parts would fit the clones.
As I mentioned earlier it would be a good upgrade.
90cummins

 

[90cummins]

My newest Yanmar project.

I acquired a Landa pressure washer a couple years ago from a friend who was moving to Virginia and needed to part with some equipment.
The first thing I did was remove the Cast Iron 10hp Briggs and install my 9hp L90 Yanmar diesel that I had previously rebuilt with a new piston & rings. The original piston was broken from I assume the use of starting fluid.
Once the engine was installed I fired it up for a test and couldn't get any pressure.
It's a Giant brand zero trapped pressure type with a slow pressure rise when the trigger is pulled and it refused too build pressure so I moved on to plan B.
I had an old adjustable regulator laying around on an electric drive Cat Pump so I decided it was time to swap it out and finally have a high capacity pressure washer.
The pump is a General T1011 best I can tell. This pump shares many common parts with the T1011 2000psi, TS1021 3000psi and TS2021 3500psi but not knowing which pump I have I've set it for 2500psi..
The pump belt driven and under load is currently turning 1300 rpm and the engine is at 2800 rpm.
The pump is rated at 5.6gpm at 1450rpm & 4.5gpm at 1125rpm.
I installed a 5000psi gauge in the line and ran it up too 2600psi with no effort.
The Yanmar has electric start and a charging coil so I made a mount for the battery and necessary wiring to save my shoulders.
These Yanmars are amazing little engines needing only 1 good pull to start but you can't beat electric.
My current nozzles are rated at 3 gpm so new 5.5gpm nozzles are needed to fully utilize the power.
I ordered new #7 nozzles to utilize the full capacity of the pump.
The only thing I have left to do is fabricate a belt guard.
This is my 3rd Yanmar powered project and perhaps the one that will get the most use.
This machine came with over 100 ft of hose, wand and an adjustable nozzle.
This engine has a crankshaft for driving a generator so a tapered bushed bore pulley was used.
The end is taped to prevent corrosion.

90cummins

 

[Industrial Toys]

Nice job. Just curious. Does Yanmar have different versions of engines for direct drive versus belt drive? I had a catastrophe fifteen or so years in with my low hour Diesel Mule. The crank shaft broke. Long story, short, apparently, the original motor was never speced for having a belt pulling on the crank. The replacement was a beefier crank that they used in the turbo version of motor.

 

[90cummins]

Don’t know the answer to that.
Yanmar’s installation manual for the L series is very specific as to the angle the belt can pull on the crankshaft.
They prohibit drives that are above the engine.
Only fore, aft and below are permitted.
90cummins

 

[Industrial Toys]

So that obviously has more to do with the construction of the block, than the stresses put on the crank itself.