Mercuy 2.5L broken Crankshaft

[A164]

Hi,
Sad sad,,, day today.
Took my merc 2.5L 260HP apart because I thought that top crank bearing was gone. It turned out to my shock that my crankshaft was broken at cylinder 3.
Is this a common failure on theese motors, or have my luck just ran out?

Below link to youtube show the failure.

https://youtu.be/OaDEZl7onVw

//// Thomas

[LakeFever]

Plastic cage bearings... yikes sorry to see this, its not fun to break a motor. Not to many people post about broken crank here, first ive seen since joining but there are many complaints of the plasticcage bearings failing. I wonder if this is what happened first which led to crank breaking?

[25two.stroke]

Dammit

[mach351]

I wouldn’t say it’s common....cranks are usually pretty tough.

These things happen though.....

dont forget, that crank is 20-25 years old

[CI STV]

I broke the crank in my old 260, way back when, but that was due to a piston sticking in the hole. Turns out the guys I bought it from didn’t bother to tell me it had one steel sleeve in the No 2 hole, and I was making a pass when the piston in that bore stuck at about 9200 or so, snapped the rod off, windowed the block and broke the crank all in one go. When I pulled the cowl off, the flywheel was all wobbly. Took out the stator too. That was some carnage.

[us1]

Its not very common. Get a new crank and get her going again.

[Smalltownbassin]

Lost mine about 2 months ago. Broke crank at #6.

[A164]

Just thinking, completly new crank costs more than i can buy a deasent 225hp optimax. hmmm. I dont know the complete history of this crank as I replased it during my initial restore of this motor 8-ish years ago. But it was in very good condition then, and the bearing surfases looks also very good now. And it is not a plastic cage brake down that is the issue, they look fine.
Sp now the situation is eighter to find an secondhand replacement or another engine.
Saad thoug because i like the intimidating sound of it, which just makes other to back down just for the sound.
thanks for all the replys so far,,,,.

[us1]

If the balance is off it can break but that is rare.

[LakeFever]

All the 2.0, 2.4, and 2.5's share the same crank aside from the two types of bearing end do they not? Cant be all that hard to dig one up

[Smalltownbassin]

I've been looking since I broke mine. Had a few that got my hopes up but never panned out. I used to see them all the time until I actually needed one.

[A164]

I still have my original crank, but it was replased because the engine had been submerged. And becaues previously owner did not diamantle the engine, it suffered under salt water corosion.
Picture her shows my original abowe, and the replacement below.

[nitro_rat]

All the 2.0, 2.4, and 2.5's share the same crank aside from the two types of bearing end do they not? Cant be all that hard to dig one up

No, there are two types of center mains, shouldered or not. 2.0 and 2.5 use the shoulders, 2.4 don't. 2.4 crank only works in 2.4. 2.0 and 2.5 will swap as long as center mains stay with block and top cap stays with crank. 260 "small bearing" cranks use the same crank end as 2.0 so top caps will swap between those, 260 cap has a retainer plate for the bearing, 2.0 does not.

There are 7 and 9 ring non-oiler cranks, 9 ring from old fishin' 2.0's, 7 ring from 260's.

Early cranks have shoulders on the rod journals for bottom guide rods, late don't. bottom guide rods can be used on early cranks, non-shouldered rod journal cranks have to be top guided.

There is a lot of interchangeability but you can get in trouble if you don't know what you're doing...

[CVX20SPRINT]

Good used cranks get snapped up pretty quick.I looked for one for a 2.0 for quite a while.Actually looked at a couple that seller said were good that ended up not being.I finally parted it out.

[kellytheaker]

Thanks for the education on the cranks -
isn't the best to just buy a promax if their reasonable vs the crank right now -
?