Expert advice needed-120 Merc - u-joint/coupler prob.? -

[tjaizmopars]

1975 Galaxy 16ft 120 Merc. I/O -, when purchased seller said outboard coupler was bad , put water muffs on and ran for maybe 5 min,fwd & rev seemed to work fine,then prop quit spinning & temp started to rise-shut it off then -does this sound like coupler/u-joint assy.?- unit did not make any loud or unusual noises while running but when prop started to slow smelled a little funny-to change this assy. - pull motor or pull outboard,or any other troubleshooting needed -all expert advice greatly appreciated.<br />Thanks TJ

 

[horndog]

Re: Expert advice needed-120 Merc - u-joint/coupler prob.? -

without seeing it and what it is doing its hard to tell. Sounds like something spun in there and its probably the drive shaft

 

[Trent]

Re: Expert advice needed-120 Merc - u-joint/coupler prob.? -

Very common problem. Pull the engine to replace the coupler. Also pull the outdrive. You need to check engine alignment after you install a new coupler. Check rear engine mounts for sagging. Boat that old will have sagging mounts which is the number one cause of coupler failure.<br /><br /> Coupler

 

[Bondo]

Re: Expert advice needed-120 Merc - u-joint/coupler prob.? -

Classic Symptoms....<br /> seller said outboard coupler was bad <br />A Sure Sign.... <br />then prop quit spinning <br />Makes sence...<br /> temp started to rise <br />Yep, Waterpump isn't turning anymore....<br /> smelled a little funny <br />Burning Rubber ????<br />Like Trent says, Pull'm Both... It's Really not that bad a job....