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05 Merc 125 help please

CHECK16

CHECK16

Well-known member
Hey guys I am having some issues with my little 4cyl.
I was going across the lake at wot and all of a sudden the motor just shut down and will not turn over.
My first thought is its done but I noticed the shift lever will go into forward position but will not go in reverse position.
I have drained the LU and no metal shavings at all.
Any advice is welcome. I am just looking for a starting point. Lower unit or power head?
Thanks in advance .
Tony
 
I can rotate the engine backwards for a bit but when rotating forward it hits a point and stops. I am just wondering if something broke in the LU that is causing this.
Anyone ever had this happen?
 
Maybe drop the lower unit and the motor will spin free and you are only looking at a lower unit repair/replace?
 
Well the Lower seems to be welded to the mid section. I know this should be easy but it will not budge. I've taken a wood block and a hammer to tap on it but no luck.
I don't want to beat the crap out of my lower trying to remove it.
Any tips from the pros?
 
Uh oh. I had hopes of a seized lower unit. Sorry to see this. It looks mighty dry in there?
 
I was hoping for a lower unit problem myself but no luck.
Yes it does look dry jim. It was always full of oil and I checked the oil output a couple months ago.
The engine never made any showing of something wrong. It was running perfect the moment it blew. The cylinder is trashed. I just don't think I want to spend the money on this motor.
So it looks like the V6 search is on.
Here's the exhaust side.

20150519_145614_zpsfruvgo9j.jpg
 
Sorry to see that! Typically bullet proof motors. Curious: what oil were you running and what rpm did you spin that motor when at WOT?
 
Always ran Pennzoil and with the 26p Laser II I ran it would spin about 5100 rpm at WOT. It had to be that something happened to the carb on that cylinder. The other 3 cylinders look brand new still. I still see the crosshatching on them.
 
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Good oil and the right size prop for that engine, terrible this had to happen to you. Had to have been some failure you couldn't avoid. Luck (bad) of the draw :(
A 2.0/2.4/2.5 motor will be fun, if you can find a mint one used. Just gotta pick up some 125 stickers :surf:
 
Does the wrist pin in that cylinder look funny and/or is the reed valve still in one piece?
 
I finally got it tore down and here is what I found. The wrist pin is in good shape no signs of abnormal wear.
The reed valve on that cylinder shows damage but I'm sure that was from the piston coming apart.
It sucks that this engine doesn't have a removable head. The cylinder could be cleaned up but the combustion chamber is trashed.
20150524_125129_zpsycksp98y.jpg
20150524_125328_zpsojog66si.jpg
20150524_162139_zps62ujlchg.jpg
 
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