started out with a bad prop & now i"ve been directed to this section for the next question about the current problem. If this is the wrong forum i apologize, but the prop section said to post here. Anyways i have acquired a new prop for my merc 115 6 cyl. it was suggested i change the impeller & i bought the impeller. I take the lower end off and change the impeller & re install the lower end the drive shaft won't engage so i turn the prop and the shaft won't turn i take the unit back out & put it on the bench if i turn the prop or the drive shaft the oppossing shaft will turn, but the application of the lightest amount of resistance ( me putting my hand on the opposite shaft) will stop the rotation. I can feel it wanting to turn but there is no real force to it. previously the prop was replace as it was determined my had spun the hub and was damaged on one of the flukes/fins (not sure what the tech. term is for them ) the boat would take off & attempt to plane but would act like a car with a slipping clutch. I did take the boat to a local boat dealer/repair shop & the manager came out & looked it over & performed some inspection of the lower end with it in nuetral,forward & reverse he applied pressure to the prop. He sais my lower end looked good get a another prop. My question is did i disengage the shaft or do i have a problem im my lower unit the motor is missing the plate with the serial # but appears to be from the early 70's. I would appreciate any help as i am mechanically inclined the vast majority iof my experience is with cars kinda new to outboard repairs thank you
