Stingray mercruiser 3.0 engine problem

Ash stingray

Recruit
Joined
May 21, 2022
Messages
4
Hello and thanks to anyone that can give me an idea of what this might be.. so out running today ran great. All systems ok oil, not over heating nothing wrong at all. And I heard what sounded to me like something being spun out or a brake loose kinda sound. Then nothing all dead in water no restart. No milk in oil. Plenty of batteries power no visible broken belts of leaks nothing ???? Any idea " maybe timing chain ?
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Hello @Ash stingray and welcome aboard.

MerCruiser have been pumping out the 3 litre engine since the late 60s. Can you give us an idea of the year? Or better yet, an engine serial number?

Chris...
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
6,914
Hello and thanks to anyone that can give me an idea of what this might be.. so out running today ran great. All systems ok oil, not over heating nothing wrong at all. And I heard what sounded to me like something being spun out or a brake loose kinda sound. Then nothing all dead in water no restart. No milk in oil. Plenty of batteries power no visible broken belts of leaks nothing ???? Any idea " maybe timing chain ?
In additon to the info chris wanted some more on what happened? Just stopped running? Does it turn over via the starter and not run or dies it not turn over at all?
 

Ash stingray

Recruit
Joined
May 21, 2022
Messages
4
Dead as in key on, no beep, no gauges or have beep/gauges but no crank/turn over or engine turns over but does not start/run?
Dead as in will not start. Will crank but haven't tried since I heard the sound checked everything this morning. Kinda scared to keep trying to turn over. Sounded like something internal came undone like a belt or chain or so mething being striped out
 

Dubed

Petty Officer 1st Class
Joined
Sep 3, 2021
Messages
373
I had something similar happen on my 3.7. Just died no explanation, turned over but sounded and felt odd. I took the distributer cap off to check the points and distributer wasn't turning when turning over the motor. Turned out the key on the crank sheared so timing gears weren't turning. It was weird occurrence and a lot of work to replace an 80 cent part
 

dubs283

Vice Admiral
Joined
Jul 27, 2005
Messages
5,338
Dead as in will not start. Will crank but haven't tried since I heard the sound checked everything this morning. Kinda scared to keep trying to turn over. Sounded like something internal came undone like a belt or chain or so mething being striped out
At this point you need to check all electrical connections and components. There is some great troubleshooting guides in the stickies at the top of the thread page.

It's quite possible something mechanical has broken, however don't fret. You will need to try to start the engine in order to solve the issue and you can't break what is already broken
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
First thing we need to do is see if the problem is engine or drive. Remove the drive (10 minute job, video on how in the stickies) and give it a try.

Chris...
 

Ash stingray

Recruit
Joined
May 21, 2022
Messages
4
Hello @Ash stingray and welcome aboard.

MerCruiser have been pumping out the 3 litre engine since the late 60s. Can you give us an idea of the year? Or better yet, an engine serial number?

Chris...
1998. Alfa 1 3.o inboard
First thing we need to do is see if the problem is engine or drive. Remove the drive (10 minute job, video on how in the stickies) and give it a try.

Chris...
Lower unit oil looks great. Had it almost turn over after few tries. Going to pull plugs and have a look
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,587
So the end of the stingray ;!!! Bent push rods and totally fobar cylinders !!! Need a new 3.0 any ideas where to find one
Michigan motorz is a good source for new and reman. however you could just rebuild yours for about half the cost. Contact your local engine building machine shop.
 

kenny nunez

Captain
Joined
Jun 20, 2017
Messages
3,352
I checked with Michigan Motors who sell rebuilt engines, however they are out of stock at this time. Marine Power has new ones but @ $4500.00 plus freight is a lot of $. Your engine probably can rebuilt locally by a good rebuilder. From your description the timing gears or the crankshaft key may be the cause of what happened.
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,348
I think what’s happened is that the engine has stopped (due to an electrical issue or pulled safety lanyard) and the noise you heard would be the prop still turning as you slowed down. Makes a hell of a clatter when it does this. That’s where my money is. Hope I’m right.
 
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