Merc 175 Lower unit trouble

[jdp8488]

When I bought the motor, and we tested it, it did not have a prop on it and it shifted fine.

I put a prop on it and took the boat out and it would grind shifting into forward only. Reverse is ok.

I could get it in gear everytime, but it would grind a lot, so I would have to give it gas and it would catch.

When I was out I did some full speed runs, and felt the lower unit just to see if it was getting hot or not. It was cool, not warm at all..

I got it home and drained the oil, about 80% water and 20% burnt oil.

I am surprised it didnt burn the gears up. Is this thing toast? Or is there anything I can do to get it to quit grinding? It shifts all the way into forward on the motor, so I dont believe its the controls..

Thanks for any help. .-Justin

 

[Laddies]

Re: Merc 175 Lower unit trouble

Try adjusting the cable to pull it farther into fwd gear, if that don't work or you can not get it into rev. then the clutch dog is bad. Probably why it did not hve a prop on it.

 

[jdp8488]

Re: Merc 175 Lower unit trouble

Already adjusted it to pull it all the way into forward. Is the clutch dog much trouble to replace?

 

[Chris1956]

Re: Merc 175 Lower unit trouble

You will need to rebuild the gearcase with the correct clutch dog, shims, gears and bearings, as is necessary upon inspection. Special tools are required as is special knowledge. You might pick up a used LU and install it. it will likely be a bunch of $$ cheaper.

 

[Laddies]

Re: Merc 175 Lower unit trouble

To replace a clutch dog in your engine you will need a spanner to remove the carrier nut, a puller to remove the carrier and a manual so that you have a clue to it's replacement. The bit about shimming is someone talking that apparently has never had one apart, a lower unit may be repaired and not shimmed as long as you replace all shim backs to the original position in the case or that the case is not replaced.

 

[jdp8488]

Re: Merc 175 Lower unit trouble

I found a tool on ebay, and will get the puller. I will only replace whatever is worn. Hopfully just the clutch dog and forward gear. It goes into reverse just fine. And a whole rebuild kit is about $600. Is there anywhere I can buy seperate parts for what I need instead of a whole gear assembly kit? Thanks for the help. If its going to cost more than $250, I will just get a lower end off craigslist..they typically sell pretty cheap. Thanks for the help.

 

[Laddies]

Re: Merc 175 Lower unit trouble

Here's a site with parts and prices and also merc part numbers if you buy locally. http://www.mercruiserparts.com/SelectModelType3.asp?class_id=2

 

[jdp8488]

Re: Merc 175 Lower unit trouble

The parts are pretty pricey. Since it was pretty much all water in the gearcase, could simply flushing it out and putting new oil in take care of the grinding problem?

 

[Laddies]

Re: Merc 175 Lower unit trouble

No.

 

[jdp8488]

Re: Merc 175 Lower unit trouble

hm. well i guess ill be gettin a manual and some parts. thanks for the help.

 

[Faztbullet]

Re: Merc 175 Lower unit trouble

What year engine do yor have? If its the older pin shift like a inline(1980?) gears and dog are NLA.

 

[jdp8488]

Re: Merc 175 Lower unit trouble

Its an 86. I believe I have already located some parts for it. There was oil in the water pump housing, the impeller was in terrible condition, yet it still pumped well. The o-ring on the piece right under the water pump and all the gaskets was busted, so thats how I believe all the water got in, and of course how the oil got into the housing... I have to get the tool to take off the nut near the prop shaft and will let you guys know how the gears look. I am wondering if I should tear down the top part of the unit where the drive shaft connects to check all the bearing, that would require another tool. Ive heard of people cutting these nuts off around the prop shaft. I dont see a way to cut it with out messing up the bearing housing...

 

[Laddies]

Re: Merc 175 Lower unit trouble

while the driveshaft end is apart replace all the seals and gaskets and o rings on the shaft as well as the impeller. If you have have problems with the carrier nut we can tell you how to drill and break it also if the carrier is stuck we can give you a east way to break it loose while your doing the clutch dog replace the prop shaft seals and the o ring on the carrier.

 

[jdp8488]

Re: Merc 175 Lower unit trouble

quick question.. when messing around the motor, i noticed a round black thing with a black and white wire comming out of it on the trim unit. it is has a round casing and it is right where the center tilt punp meets the transom bracket.. is this for a trim guage? its not hooked up to anything and was just curious about it.