125 Lower Unit Removal

[RetrActv]

I've never removed the LU on my '98 Merc 125 (Owned it 1 year). I want to change the impeller.

How hard is this to do? I'm going to get a book from the library tomorrow, but is there anything special to look for that the book might not cover? Is it just 5 bolts and drop? How does one remove the shifter rod, and then reinsert? That's the part I'm worried about.

 

[emckelvy]

Re: 125 Lower Unit Removal

Not hard, all the bolts are obvious and there's no bolts hidden by the trim tab, as on the older Inlines.

Regarding the shift shaft, the upper shift rod and the shift shaft in the lower unit have splines, so they just slide in/out of each other. Be sure not to put any grease on the top of either the shift shaft or driveshaft when you reassemble; just on the splines themselves.

Most folks find it easier to leave the remote control in "Neutral" for this job; take care not to inadvertently move the shift shaft on the lower unit while you're working on it.

Reassembly is reverse of teardown, have someone turn the flywheel in the clockwise direction while you're inserting the lower unit, in order to engage driveshaft with crankshaft.

One last word of caution, pull all the spark plug wires off to avoid loss of body parts!

BTW if you search this forum you'll find tons more info about doing an impeller job. Get your parts from this site or check out my favorite, www.boatfix.com

You can also look up parts at the factory site, www.mercurypartsexpress.com

Cheers.........ed

 

[Texasmark]

Re: 125 Lower Unit Removal

And insure that the tube from the top of the water pump makes it into the hole in the bottom of the power head and if you have a speedometer tube or anything else on there that they get hooked back up too.

The water pump is eccentric so when you try to push the impeller in it is hard on one side and easy on the other. Another set of hands and some soapy water on the rubber help tremendously. The crankshaft turns cw lookind down from the top when you are pushing the blades in.