25 HP Tohatsu Crankshaft

[imported_bowfisher]

I have an older 25 HP Tohatsu I took on a trade. I know very little about them, but it was running great at one time until the owner hit a rock bar. Smoked the prop of course, and now the motor will not idle down. The problem seems to be a timing issue possibly internal. I have been told these motors have two piece crankshafts and it has probably slightly spun or twisted. Is this true, and if so is it a replace the crank scenario or can it be repaired?

THANKS!

 

[Sea Rider]

Re: 25 HP Tohatsu Crankshaft

Remove both plugs and kill cord, rotate flywheel CW with hands or rope, does flywheel rotate freely ? if so, crankshaft is ok, if rotates with difficulties crankshaft has internal issues. Place forward gear, rotate flywheel again, if prop spins with difficulties, tail inside issues due to rock hit. The engine is completely repairable, just determine the trouble area.

Happy Boating

 

[pvanv]

Re: 25 HP Tohatsu Crankshaft

Yes, it is a pressed crank. Usually will only slip out of time if really really over-revved. But could maybe have slipped if the prop hit the bottom. Normally you would wreck the LU gears or twist the driveshaft first, though. Uneconomical to repair.

 

[imported_bowfisher]

Re: 25 HP Tohatsu Crankshaft

Thanks guys, this motor could have been over revved also. Knowing the person that was operating it anything is possible (novice). The prop that was on the motor was a vortex with the plastic hub, not the rubber hub so it did not slip. The prop took a ton of abuse with the impact. I checked the flywheel key for possible partial shearing creating the out of time symptom, its not bent or sheared. The prop shaft is still straight and it goes in and out of gear fine with no noises. It just idles very high I would guess at around 2000 rpms give or take. Everything is pointing toward a slipped crankshaft, just not sure if it can be put back into time properly if this is the case.
The motor was a great running motor and very fast on a 16ft Jon Boat, hate to scrap it.

 

[TOHATSU GURU]

Re: 25 HP Tohatsu Crankshaft

It can be pressed again. I think it's "Ackermans" in South or North Carolina.

 

[Star]

Re: 25 HP Tohatsu Crankshaft

If the crank has sliped checking piston at the top of stroke and top dead center mark on cam to mark on engine block.

 

[pvanv]

Re: 25 HP Tohatsu Crankshaft

2-strokes do not have cam shafts.