Engine Coupler

[Leedanger]

Hey boys....
Can a seized up engine coupler restrict an engine from rotating? Working on a Merc 260 with an alpha one #5424302 and I can't turn the engine by hand at all. I got the cylinders soaking, but I was wondering meanwhile if the coupler could be the culprit.

[stonyloam]

The coupler is simply a means of connecting the engine flywheel to the outdrive input shaft. As such it can not "seize". However the outdrive itself can, and prevent the engine from turning over. You need to pull the outdrive to check it. The outdrive always turns when the engine turns, whether in gear or not, the only way to disengage it is to remove it.

[TilliamWe]

Yep, exactly what stony says. remove the drive, try turning the engine over. It it turns, your drive is seized. If the motor still won't turn, it's seized good!

[Bond-o]

Ayuh,.... as stated above,... If ya don't have the drive off yet,...

Yer 6 or 8 nuts away from knowing whether ya got a junk motor, or junk drive.....

[UncleWillie]

If it absolutely, positively will not move even a hair, it is more likely the engine.

If it will move even the slightest bit then it could be either.

The coupler,u-joints, and the rest all have a little play in them and would likely give a little wiggle room.

[Leedanger]

wah...wah...wah....Motor toast. Thanks for playin'

[TilliamWe]

wah...wah...wah....Motor toast. Thanks for playin'

Sorry to hear that.

[HT32BSX115]

Now is the time of year for all the new threads on frozen engines and cracked blocks!

Poor (or NO) "winterization" will result in cracked blocks, and leaking risers and riser gaskets will result in water sitting in cylinders (with open exhaust valves)

It''s just simple high school "Physics".


Cheers, Y'all!


Rick