1992 Merc 3.0L high oil consumption, need advice

[griffin800]

Re: 1992 Merc 3.0L high oil consumption, need advice

well... I have bad news...

The engine has blown a hole in it... in the rear by Cylinder 4, right under the manifold.

It's quite large... golf ball sized...

I assume it was a thrown rod?

To be honest... I had half a mind to not post about it on here because... I don't want two things...

1. to assign blame on anyone for telling me to run it, because that's not how i feel at all... or...

2. to have anyone else scold ME for running it, even though i knew it had issues

"It is... what it is..." or so they say

As the story goes... I took it out in the evening to nights ago... oil level was fine before going out... warmed it up and trolled across the no wake zone bay... got into the main lake... oil pressure was fine... idling fine... no smoke.. no rattling or knocking... no high water temps...

...got it on a plane before 4000 rpm... backed off to 3100 on the tach... and while cruising along... heard a loud "pop"... not so much an explosion sound or a boom, but a pop and then the boat slowed down immediately...

i think it may have been still running on 3 cylinders for a moment, but i'm not 100% sure... I turned the key off as quickly as i could but if it was still spinning with loose parts inside i think it may have caused other damage...

...somehow, the starter housing was blown off the engine, and into the bilge....

I didn't realize this at first... but after I got emergency towed back to the marina... I was marvelling at all the oil that the engine had leaked into the bilge and checking to make sure i wasn't taking on water, and going to be pumping the oil into the lake... and i noticed the starter just sitting there... no wires attached to it... just sitting there...

so in a nutshell...

catastrophic engine failure.

My guess is that running low on oil that one time smoked some bearings? weakened things up?

For it to be so sudden and violent seems odd to me... but...

in any case...

i'm not sure if i'll be fixing it this year or putting it away for a while.

anyone have an engine for sale ?

i was thinking long block reman for $1700 and swap what's left of mine over to it...

i'll take pictures of the carnage and put them on flickr.... it'll be... educational...

-Gavin

 

[alorio1]

Re: 1992 Merc 3.0L high oil consumption, need advice

Sorry to hear bad news about your engine, but if you are considering swapping it in as a core on a rebuilt long block, I don't think it qualifies with a hole in block. If you are going to do the work your self, you will have all winter to take it apart and research for a good price on long block or even a complete engine for sale. I scored a complete outdrive from a boat that had damage from a wreck, while being towed, and paid 400 bucks. I bought it but did not need it at the time, so it's just my spare.

 

[Silvertip]

Re: 1992 Merc 3.0L high oil consumption, need advice

If bearing damage had happened during the low oil run then the oil pressure gauge should have shown that. Bad bearings are the main reason for low oil pressure. A broken piston skirt, a broken rod, a broken piston in the wrist pin area or swallowing a valve all can cause catastrophic damage. But look at it this way, many people have died walking out of a clinic after having just received "good to go" from their doctor after a complete physical. Sometimes "stuff just happens".

 

[griffin800]

Re: 1992 Merc 3.0L high oil consumption, need advice

If bearing damage had happened during the low oil run then the oil pressure gauge should have shown that. Bad bearings are the main reason for low oil pressure. A broken piston skirt, a broken rod, a broken piston in the wrist pin area or swallowing a valve all can cause catastrophic damage. But look at it this way, many people have died walking out of a clinic after having just received "good to go" from their doctor after a complete physical. Sometimes "stuff just happens".

With my luck I'll probably be that guy

I have a doctor's appointment next Tuesday as well... guess I'm glad i got my boating in before then

Thanks for the explanation, I'm going to take it all apart for fun to learn about it... and i've found quite a lot of used merc 3.0 engines for sale locally...

 

[Silvertip]

Re: 1992 Merc 3.0L high oil consumption, need advice

If you are pulling the engine out of the boat and doing a complete teardown, then be certain to mark the main and rod bearing caps and also their orientation so they go back on the same journals and in the same orientation they were removed from. In the event the block and rotating assembly rebuildable you will want this stuff put back correctly.

 

[griffin800]

Re: 1992 Merc 3.0L high oil consumption, need advice

Question...

I've been doing a lot of reading... about the sterndrive gear ratios...

and one thing i noticed about my lower half of my stern drive is that its a replacement of some sort... clearly different than the upper half.

The upper says 1.98:1 on it, but.... if someone used a lower half from a 2.0:1 drive, and thought they were the same... according to this thread... that would make it a 2.4:1 ratio drive...

would this have "lugged" the engine if this was the case? Since i've got nothing but time on my hands I'll split the upper and lower again and look for marks but there were none, no serial or part number, nothing.

i was thinking it may be a "sport engineering" drive...

Assuming my tachometer read 100% accurately... would a 2.4:1 ratio drive on my engine with a 19 pitch prop be "lugging" it all the time.... making it have a pretty horrible hole shot when even slightly weighed down... and keeping the top speed to only about 31 on open smooth water... with the max RPM at 4100...

just tryin to think of another reason for such strain on the motor when everything else seemed ok.

-gavin

http://forums.iboats.com/mercruiser-i-o-inboard-engines-outdrives/alpha-gen2-2-0-lower-unit-differences-471939.html