Slipping motor what to do

[boaterntexas]

My 1976 115 hp merc has been having so drive problems. We ran aground and ran the motor through some really thick mud, the motor seemed to of slipped a couple of time but nothing serious, since then I have changed out the impeller. the first trip in the water with after the runaground/impeller change, the motor started bogging down, which then turned into slipping, no force on the prop at all, it appreas to be turn some, but not enuff to move the boat, the motor sound like it is reved up all the way. Any Ideas on what the problem could be, diagnostics, and estimates of cost to fix the problem. Oh yeah, the after the impeller change the motor ran fine out of water. also when I changed the impeller it was really ill fitting when I was putting the housing back on. there is alot of water comming out of the top two "exhuast" slots. I had lots of trouble getting the L/U back on and the shaft lined up properly, could there be a bad connection there. also the copper pipe that was there, could it be not connected to somethign up top that it is suppose to be connect to. ONe more thing, there was a screw that went through the impeller housing that seemed to never get tight, it was the one closes to the prop, the one that was not a bolt it went directly into the Gearcase, is this normall<br /><br /> so this post is so long winded and rudundent form other post, but I just want to provide as much info as possible. <br /> thanks alot guys.. <br /><br /> Thomas

 

[Yepblaze]

Re: Slipping motor what to do

Your propeller has "spun a hub" it can be repaired by a qualified propeller shop or replaced.

 

[dmessy]

Re: Slipping motor what to do

You spun the hub in your prop. Pull the prop and take it to your favorite local prop repair shop. it'll cost around $100 to repair. The water coming from the exhaust slots is normal, make sure your telltale(pee)stream is strong. This will tell you if the water is pumping. Another "seat of the pants check" is to run your motor and feel all along the head. Should be no more than around 140 degrees. Too hot to touch and you got water flow problems. Finally , sounds like the screw to your water pump is stripped out, helicoil to repair...good luck.

 

[ob]

Re: Slipping motor what to do

Boaterntexas,Sounds like one of the bolt holes on your waterpump housing was probably stripped out not allowing bolt to get tight.Now to the problem of slippage.Sounds like a classic case of a spun prop hub.Visually inspect the hub insert of the propeller.You can get it rehubbed at a prop shop or dealer service center.

 

[boaterntexas]

Re: Slipping motor what to do

thanks alot for you help guys but I just remembered one more thing. when the motor finally quite spinning the prop, water quit comming out of the peehole.. any connection here?

 

[JB]

Re: Slipping motor what to do

Howdy, BoaternTexas.<br /><br />Both the gearcase (prop) and the waterpump are driven by the driveshaft.<br /><br />Pull the prop. Turn the flywheel by hand and see if the propshaft turns, turn the propshaft and see if the flywheel tries to turn.<br /><br />The two symptoms may be related and they may not.<br /><br />Inspect the inner part of the prop for broken or slipping rubber hub.<br /><br />Good luck.

 

[ob]

Re: Slipping motor what to do

Worst case scenario,The driveshaft splines are stripped which may show propshaft movement when in gear rotating by hand yet will break loose under load.

 

[boaterntexas]

Re: Slipping motor what to do

there is rubber on the prop, appears like it is being squeezed out.

 

[boaterntexas]

Re: Slipping motor what to do

there is rubber on the prop, appears like it is being squeezed out. now when I changed the impeller, I did stugle with getting the chaft back in place, if this is damaged, what kind of money am I looking at to get it replace.. See I'm asking this becuase I'm thinking of restoring the boat if it's within reason.

 

[ob]

Re: Slipping motor what to do

Driveshafts are big bucks.$400 + for new one.If just the prop hub is spun it should have no effect on the waterpump unless the pump key is coincedently failing.Try blocking prop blade with a piece of wood while engine is down in gear and try rotating the flywheel and see if slippage occurs either at the prop hub or driveshaft.