Force 50 "clunking" intermittantly at full throttle

[go-nucks]

Just bought a boat w/89 Force 50hp outboard. The test drive was fine, as was the first 30 minute ride I took from my place. "no previous problems" according to previous owner. The problem started the next trip. About 20 minutes in, the motor started "klunking/kicking". You can hear/feel the klunk throughout the boat. By the time I got back to shore, it was occuring about every 15 - 30 seconds. At slow speed, it does not seem to klunk. I then drained/refilled the lower unit oil. Old oil was a bit dirty...not bad though...didn't see/feel any solid bits in oil.any thoughts?

[12Footer]

Hmm..Pull the prop, and check the hub and spline. It could be iether. But your approach to this problem has been on the money up till now. That clunking usually indicates severe gear damage.But also check the shift linkage, to make sure it is tight. sometimes a link arm could loosen-up, and allow the gear train to drop out of forward into neutral (above the threaded shaft connector inside the cowling). See id there is any 'slop' in that sahft too.But this is odd allready.

[steelespike]

Could be a worn shift dog.This is a normal wear item in the lower unit gearcase.And the clunck is a classic symptom.On most motors the dog is splined to the prop shaft and slides between the forward and reverse gears to ingage them to the shaft.Each time you shift it wears a little.If you shift to hard or the idle is too high it will wear prematurely.Shift crisply without dragging or jamming it in gear.With a manual it should be a fairly easy repair.

[go-nucks]

Checked the prop...no slippage...time to invest in a manual as I'm pretty new at this.