What to Do After Running with No Oil

[CTsalt12]

Hi All,

I had an issue last fall when I ran the boat with no oil during one trip for a short period of time.  The alarm gave out unfortunately.  The boat would not get up on plane, and the engine would peter out and shut down.  It would run at idle but sounded like crap.  I tried to get it on plane maybe 2-3 times, then realized the issue and refilled the oil as well as putting oil direct in the fuel tank.  It sounded better almost immediately.   No issues running it since then, probably 4 trips since that issue.  It does sound different at idle, to me it sounds like a knock or a rattle.  No noticeable loss of power.   Did all annual maintenence like thermostats, LU oil, impeller. 

I'm not mechanically inclined enough to work on the big issues myself.  What am I looking at here?  Is it even worth bringing it in for a diagnosis? It's a 97 engine, no hour meter, but I estimate it's seen 300 hours in the three years I've owned it.  I also put it though some abuse with water in fuel issues.  Carbs cleaned since then of course. 

Bottom line, what kind of repairs can I expect?  And is the engine worth these repairs?

[fitz73222]

Not a good thing CT,
There is no doubt the engine received damage from this, the question is how much and the only way of knowing is a complete teardown. My opinion is that it has some bearing damage in the main journals, rod bearings or wrist pin bearings from overheating from lack of oil. Being a '97 model the engine isn't worth much especially with this kind of damage. You could easily drop $2000+ into it to have it professionally rebuilt, the parts are very expensive and you have to buy new bearings or you're waisting money. I would start looking for a another engine.

[CTsalt12]

Thanks fitz.  Sort of what I figured.  I've mentally prepared myself for the prospect of having to buy a new engine. 

Short of a complete teardown and dropping a few thousand, is there anything that can be done? 

Otherwise my plan is to run it until it dies, maybe I get lucky and get another season out of it. 

[GoneFission]

 

[fitz73222]

Too bad you don't live in Florida, I need one of those for a parts motor! Anyway, nothing in a can is going to bring her back from what happened to it. You can run it till it grenades, just hope you're not in a spot where that would be extremely inconvenient!!

[Aswaff400]

i'd run it till it blows, you may get 3 hours or 3 more years out of it. keep your tow boat us/ sea tow up to day

[CTsalt12]

i'd run it till it blows, you may get 3 hours or 3 more years out of it. keep your tow boat us/ sea tow up to day

First thing I make sure to renew every year, before insurance even. 

[RickK]

The newer engines have protection built into them that forces the engine down to idle when the oil reserve gets low. My '91 Yammy has it and it uses it all the time.  This helps prevent damaging the engine.

It does sound different at idle, to me it sounds like a knock or a rattle.

That may not be a good thing though, as Fitz said, but agree that you should "run her til she drops".

[czizza]

You have been out 4 times without issue ... This is a two stroke motor so the bearings are different then the ones you find on a 4 stroke. The bearings on a two stroke have rollers in them so they are less friction prone then the sliding bearing used in 4stroke engines. In a 4stroke there is a thin gap for oil where in a 2stroke the crank runs on the rollers no gap and the rollers need oil to lube the shafts they run on.

That being said I think you are okay because the oil system would not allow you to over rev so you might be good. Just monitor it for performance issues if it lasts and you don't let the oil run low again I think you should be fine.

 

[fitz73222]

That engine has no protection mode if oil is not there. It was trying to lock up. That is why it now has a knock or rattle. It has a damaged bearing. If you were to tear it down now you would see the journals have turned blue from overheating and probably some galling on the surfaces. The surfaces cannot be ground and replaced with oversized needles, they don't exist. It will blow up, just a matter of when.

[czizza]

My bad. You are correct I did not see the sentence about the knock at idle. If you have noise then get a 5~20hp gas motor from Craig's list you can find them for about 500-800 as a backup engine and drive the old one until it dies.

Use the little motor to get her home.