Lower unit 125 HP OB

[Dave Pearson]

Took off the lower unit and found that the housing for the water pump had a portion crack and broke off. May be why it shut off last night at WOT and the overheat alarm came on. While I had the lower unit off, I was was spinning the propeller and checking the shift rod. Is it normal to hear some sound as the gears turn while it is in reverse and forward and vitually no sound when it is in nuetral. I am manually spinning the propeller and shaft. We recently hit something and I want to make sure the lower unit is ok. The drive shaft is still straight and spins ok. This is my first time taking off the lower unit. thanks for any help out there. Also, finally got my hand on another wp housing. any suggestions when replacing it. thanks

 

[eurolarva]

Re: Lower unit 125 HP OB

As long as you have the water pump off you should replace it with a new impeller. Is this a force or a chrysler outboard. Can you post the model number of the motor? This would help to identify the correct parts for your motor.

 

[Dave Pearson]

Re: Lower unit 125 HP OB

Already got a handle on the water pump parts including the impeller. Forgot to add that earlier. How should that impellar fit in its housing. Is is pretty tight? I imagine it should be. do you know about the spinning of the gears? Should there be a little bit of sound, but obviously not grinding. I drained the gear case and the fluid looks good, no water and not shavings. Thanks, Dave

 

[eurolarva]

Re: Lower unit 125 HP OB

The gears are not tight fitting. When the clutch and gear engage there is slop that allows you to turn the prop about an inch or so in either direction. This is normal. When installing the new impeller you should coat the fins with some vasoline and install it on the drive shaft with the impeller key installed. then push the water pump down onto the impeller while slowly turning the drive shaft clockwise (as you are looking down on it) until the water pump is firmly seated. This will allow the fins on the impeller to curve in the right direction inside the water pump. The tight fit is normal. I would put some blue lock tight or liquid gasket on the threads of the water pump bolts sot they dont come loose. Also put some anti sieze compound on the splines of the drive shaft that go up to the power head. There should be a grommet that the water tube fits into in the power head. use a flashlight and look up so you know where it is. If this is a force hopefully the shift shaft works for you when it is installed.

 

[Dave Pearson]

Re: Lower unit 125 HP OB

thanks eurolarva! I'll give it a shot.

 

[Scaaty]

Re: Lower unit 125 HP OB

Originally posted by Hazdog:<br /> Is it normal to hear some sound as the gears turn while it is in reverse and forward and vitually no sound when it is in nuetral.

Its fine.......slap it back together