Tohatsu M9.9B slipping in forward

[squidhunter]

I have a M9.9B Tohatsu 1986. I have it on a 12ft Tinny and recent whilst in the water the motor started revving quiet high in forward gear. When I dropped the throttle back it seemed to move ok whilst moving slowly. but once it got half throttle it seemed to slip again. There is no banging or grinding and the prop is not spun ( no burnt rubber). The motor is in good condition for its age.

 

[pvanv]

Re: Tohatsu M9.9B slipping in forward

The hub in the prop is probably shot. Normally does not show any burning rubber. Make a mark on the prop center (aligned, say, with the cotter hole), go for a run at WOT and see if the mark has moved. Probably has.

 

[squidhunter]

Re: Tohatsu M9.9B slipping in forward

thanks for the advice Paul I will eliminate that later today. - addition info - when I have it in forward (out of the water) the prop turns with little resistance apart from a clicking noise every half turn (no compression) is this symptom in line with a spun hub or could it be something else like the clutch dog ?

 

[pvanv]

Re: Tohatsu M9.9B slipping in forward

The clutch dog ears are tapered on the fwd side, to ease shifting. That ratcheting is normal. Nothing to do with the prop/hub.