[toller]

I was having starting issues with my 322 with the 18hp 3 cylinder Yanmar. Accidentally left the key turned to on, came back and cranked it while the cylinders were apparently full of gas. When I finally corrected my starting problem, when I reved the engine or under load there was a loud banging. I figured I threw a rod. I shut it down.

The motor has approx 2800 hours. It was a well-maintained commercially used machine before I bought it 15 years ago.

Question: What is my most likely damage and the best way to proceed?

Additional info; I just moved from a home with 1+ acres of zoysia to a house with a total land area of 8,000 sq ft so my plan is to sell or swap the tractor for a motorcycle.

I'm in St. Charles, Missouri.

Thank you in advance for all for the help and deserved ridicule.

 

[KellyfromVA]

More than likely, you accidentally fuel-hydrolocked one or more cylinders and bent a connecting rod. The bent rod may be hitting the bottom edge of the cylinder lining, probably breaking chunks off in the process. If so, then the engine is probably toast.

 

[ajcan]

If you cranked the engine and it ran,then revved it up it is not hydro locked.Maybe I am misunderstanding what you are are saying.
Like Kelly said if that did happen it is most likely toast.
You will not know until you tear into it though.
If it is locked up try and turn the crankshaft.If it turn then it is not locked up.
Way too many variables to assume anything.
Can you turn it over by hand or by spinning the starter?
Give some more info as to what it is doing now after the big bang.

AJ

 

[KennedyDiesel]

You should not be able to deliver fuel to the cylinders without the engine turning and the injection pump producing enough pressure to "pop" the injectors.

 

[phillijp]

You should not be able to deliver fuel to the cylinders without the engine turning and the injection pump producing enough pressure to "pop" the injectors.

322 is a gasser.

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[UrbanTractor]

322 is a gasser.

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And carburated!

 

[KennedyDiesel]

Yanmar 3 cylinder gas?

I figured it was a early diesel. I wondered what he meant saying gas...

 

[Diesel332]

The carb shouldn't have allowed too much gas in the cylinder area to hydro lock it. The starter would have a pretty hard time turning the engine over. The exhaust would also be a little misty and rich if it did have a puddle of gas sitting on the cylinder.

 

[coalminer16]

So do we know for sure if the fuel pump would have filled the cylinders? The float shutoff would also have to be bad as well correct? And I would guess that if you have a sticking needle on the float then it would fill the cylinder in short time? I would say this would be one of the first to do this sort of a thing as I haven't heard of the perfect storm of the key being left on, float sticking, filling the cylinder and then starting/running with a lot of fuel in it. If there was enough fuel to do damage then it likely wouldn't even start (12 cylinder diesel filled with water once at the mine, and a bobcat dumped into a lake are my past experiences from fixing others mistakes).

Was there a bunch of fuel that spit out after you started?

I think you also need to tear into it if you think you did damage. You might get by with just a bent rod. But a bent crank, and cracked head/cylinder's can also happen with too much pressure and no where to go. You would take the head off and measure the piston protrusion. That is how it is done with a VW diesel breaks it's timing belt to see how badly a piston contacted the head when a belt breaks.

 

[Seal]

That seems like a lot of hours for a gas engine. Time for a new one regardless!

 

[mrbeef]

Sorry to hear, I will be interested in the official diagnosis.

That seems like a lot of hours for a gas engine. Time for a new one regardless!

Not all that terrible for a liquid cooled gas engine.

 

[Alldiesel_1]

^ The little yanmar's will go alot of hours from what I'v read.

Have you checked the oil level or smelled the oil to see if it smells like fuel? If the cyl's had fuel running into them, I'd think alot of gas would've made its way past the rings. Especially with that many hours.

 

[toller]

I best tell the whole order of things. I was having difficulty starting it. I accidentaly left the key on, came back later and then cranked it. It didn't want to crank at first, and then it did, but it didn't start. I took it to Erb Equipment and they worked on it so it would start. Brought it home, started it and started cutting the grass. When it got under load in the zoysia, it started banging, but stopped when I throttled back. I was in the midst of selling my house and didn't have time to go near it again until after the move. That has been several months ago. Now I have this ailing 322 to deal with and not sure where to start or if I should just try to sell it as is along with the plow and mowing deck.

Not sure what it is worth if it were running great or what I might get as is.

There you have it, the sad tale of my beautiful tractor. :00000060:

 

[ajcan]

Seal

Not sure how much experience you have with Gas Yanmars,they go every bit as long as diesels.Aside from this find me more than 1 or 2 other gas Yanmar failures.

Toller

It makes more sense now.It may indeed have given up the ghost.If you are mechanically inclined I would do a little more troubleshooting before throwing in the towel.It would be worth more parting it out rather than selling with possible bad engine.Still reason to question if it will spin over right now or not to determine if it is locked up or not?If it does spin over is it banging around while spinning over?
If it is locked up then maybe best to let it go,if rod is bent I would look into why it bent then replace that rod and get a few more years out of her.

AJ

 

[UrbanTractor]

...I was having difficulty starting it. I accidentaly left the key on, came back later and then cranked it. It didn't want to crank at first, and then it did, but it didn't start. I took it to Erb Equipment and they worked on it so it would start. Brought it home, started it and started cutting the grass. When it got under load in the zoysia, it started banging, but stopped when I throttled back. ...

Hmmm.

As I read this, you had trouble starting and while messing with it left the key on for some time. After that, it wouldn't turn over at first, but eventually did. That to me sounds like a low battery or starter issue.

After the key incident, a repair shop got it running again.

As of the last time you used it, the engine runs, the tractor drives, but makes a strange sound under load while mowing.

To me, this does not sound like catastrophic failure.

Will the engine start and run now? Will it rev to high rpm when not under load without making the strange sound? Before tearing into it, I would want to find out more by doing some testing.

 

[KennedyDiesel]

To add to the hydrolock debate, having never seen one, is the carburetor mounted high like if it overflowed gas would run into the intake and then the cylinder? If not then you could probably rule this out.

 

[coalminer16]

Kennedy-I was thinking this but a carb basically has only two places to flow-the intake or the air filter and The air filter is mounted up on the top of the engine so it wouldn't flow out there.

Remember though that these were diesel engines fitted to run gas so the parts are stronger. Not that it can hand compressing straight fluid but the risk is a little smaller since it was built to handle diesel compression to start with.

 

[toller]

Seal

Not sure how much experience you have with Gas Yanmars,they go every bit as long as diesels.Aside from this find me more than 1 or 2 other gas Yanmar failures.

Toller

It makes more sense now.It may indeed have given up the ghost.If you are mechanically inclined I would do a little more troubleshooting before throwing in the towel.It would be worth more parting it out rather than selling with possible bad engine.Still reason to question if it will spin over right now or not to determine if it is locked up or not?If it does spin over is it banging around while spinning over?
If it is locked up then maybe best to let it go,if rod is bent I would look into why it bent then replace that rod and get a few more years out of her.

AJ

It does turn over and start, doesn't start banging unless revved up, but I'm not doing that. Maybe I will dig into it a bit. thank you

 

[toller]

Hmmm.

As I read this, you had trouble starting and while messing with it left the key on for some time. After that, it wouldn't turn over at first, but eventually did. That to me sounds like a low battery or starter issue.

After the key incident, a repair shop got it running again.

As of the last time you used it, the engine runs, the tractor drives, but makes a strange sound under load while mowing.

To me, this does not sound like catastrophic failure.

Will the engine start and run now? Will it rev to high rpm when not under load without making the strange sound? Before tearing into it, I would want to find out more by doing some testing.

I think I'll change the oil to see if I have any metal fragments. If okay, I'll get out the compression tester and see what I have, then take it from there.

Thank you for the help.

 

[coalminer16]

You can take an oil sample to send it in which costs typically around $25. Otherwise cut the oil filter open, cut some filter media off, press in a vise with a rag around it to get the oil out and then pull it apart to see any shinny parts in there. I commonly do this and it was common practice at the coal mine as well.