Lower Unit / Water Pump

I replaced my impeller last spring but I have doubts about its condition. I was going to change it out again just on account but do not feel like removing the entire out drive. Is it possible to just remove the lower unit and replace it in there or do I have to pull the whole thing? Thanks - Logan

*Alpha 1 type R mated to a 350 Merc*

Re: Lower Unit / Water Pump

You can pull just the lower, but it's kind of a pain to get everything lined back up.

Re: Lower Unit / Water Pump

You can pull just the lower, but it's kind of a pain to get everything lined back up.

Click to expand...

Ayuh,......

If you Don't pull the Outdrive,....
It makes it kinda Tough to Grease the U-joints,+ Whatnot Too.....

Re: Lower Unit / Water Pump

So idealy it is just best to remove the whole thing and not try'n cheat. Less varying circumstances, impellers are usually good for 2 years or so right?

Re: Lower Unit / Water Pump

impellers are usually good for 2 years or so right?

Click to expand...

Ayuh,.....

Or Sooner if you're boating in Sand or other Gritty stuff.....

Re: Lower Unit / Water Pump

The drive needs to be pulled once a year to check alignment, grease the ujoints, and gimbal bearing. (and clean up the excess grease), and in general look things over. This is usually done during winterization, and should include a gear lube change. Now, since you have the drive OFF, the gear oil drained, why not change the impeller every other year? Saves going thru the whole process in the spring for nothing.

Re: Lower Unit / Water Pump

Thanks for the insight Don. I guess I'll pull er and do it right the first time. As long as I got ya on the topic though, you mentioned that the engine alignement needs to be checked.. Now this may seem dumb but I have the alignment tool but am not sure how to use it or adjust the alignment. Could you borrow me your knowledge as to this procedure. Thanks again - Logan

Re: Lower Unit / Water Pump

The alignment bar should slide all the way into the engine coupler and back out with only finger pressure. If it hasn't been checked for a while there may be dirt built up and the coupler dry (Not Good) but you can put some spline grease on the AB (alignment bar) and push it in and twist a few times to get things lubed up. Once that is done, if it's still hard to pull out, then time to adjust the front motor mounts up or down to align things.
I also like to bump the bar sideways and up and down by tapping (not beating the ell out of it) with a rubber mallet to make sure the gimbal bearing is also centered.

Here is what you are trying to align.

Re: Lower Unit / Water Pump

Bond-o said:

Ayuh,......

If you Don't pull the Outdrive,....
It makes it kinda Tough to Grease the U-joints,+ Whatnot Too.....

Click to expand...

Hey! I take exception to that statement.....

Re: Lower Unit / Water Pump

So I just got in from pulling the drive, good thing I took your advice, the impeller was in shreds (probably from picking up sand and stuff). Also the plastic pick up tube was melted over where it meets the drive. Good catch.

Onto another point that don brought up (thank you by the way). Alignment.. checked mine and the tool does not seem to go in all the way hangs up around the splined coupler you can see looking through the gimball bearing. Not by much but I can see re-installing the drive would be a four letter word in its current state.

My question is how can you adjust this and how do you know wich way you need to go? Are there any tricks of the trade I could be privy to? Thanks for your sound advice guys.

Re: Lower Unit / Water Pump

You adjust the alignment at the front motor mounts. You turn the adjusting nut up or down on both sides depending upon what you need to do. Put an even smear of grease on the tool and slide it straight in till it touches, then pull it straight out. You will see if it hits on the top or bottom, then adjust the front of the engine up or down. (If the tool hits the coupler at the top of the tool for instance, the front of the engine needs to come down, which makes the coupler move up, and visa versa).

It is more difficult with a v-8 than a single front mount found on the inline engines, so make sure to adjust the mounts on both sides.

If it has been awhile since adjustments have been made the mounts may be rusted up some... that just means a little more work on your part.

This assumes your rear mounts are in good shape. They aren't adjustable but they do get soft and fail over the years.