Impeller change help needed, 175 hp Optimax

[LSVLance]

So last season I started getting a engine buzzer when idling along real slow like for long periods of time, an uptick in speed usually cleared it up right away so I figured it was time for a new impeller. It's a 2008 with just over 100 hours on it, was a test engine when I bought it in 2010, had never been titled but had about 50 hours on it.

I'm mechanically inclined and have pulled lower units before, plus I watched a few youtubes so I figured what the heck, I can handle this. Pick up the impeller kit at the local boat shop, back the boat in the shop and start disassembly. Everything comes apart pretty easily (once I find all of the bolts) and out drops the lower unit. Get the lower unit on the bench, get the impeller swapped out and everything buttoned back up lickety split. Everything looks in great shape, the impeller has a permanant curve to the splines but isn't chunking or anything and no apparant wear on anything else.

Great, I'm on a roll...another 15 minutes and this job wil be done...wrong...

Getting everything lined back up for reinstall has proved to be a challenge. First, when I pulled the unit down, the copper pipe that feeds the water up to the block came with it, is that normal? On all of the videos I watched, that pipe seems to have stayed in the block. Also, are there bushings or seals that are supposed to seal that copper tube to the block? And what about to the impeller housing?

I took the pipe loose from the white plastic tube on the housing and tried to get it to stay up in the block and it just falls out. Doesn't seem like a very tight connection for a water cooling system.

Since giving up and coming in last night, I've learned a few other tricks I wish I knew beforehand, like putting the shifter in forward before disassembly (I left it in neutral). Also the turning of the flywheel to line up the splines...I'll try that next go around.

One more question, there is a small plastic tube hooked to a fitting at the very front of the top of the LU, is this a speedometer pitot? I think the other end of that tube is hanging out the front of my engine not hooked to anything (boat speedo pickup on end of toon). If that is the case, do I need to worry about getting that plastic tube back into the fitting while putting the LU back up into place? I will verify where the other end of that tube goes beforehand but I'm 95% sure that's what this is...again, something I wish I would have know beforehand.

So my main questions are, what do I need to make sure is on the white plastic tube and copper pipe as far as seals and should that copper pipe be up into the block or on the LU during install?

I and the wife were trying to reinstall the LU with the trim up and the engine at an angle last night. I think tonight I'll get the shafts in place and lower the engine straight down and use a floor jack to slowly raise the LU into place. This seems like it will be easier to line everything up and not so hard on my arms.

Thanks for any help you can provide...need to get this done and get the boat on the lift so spring can officially start (if it ever quits freezing around these parts).

Lance

[LSVLance]

Heck, if anyone has a scan or can take a picture of the page in a service manual that has the parts list diagram for the lower unit, that would help as much as anything.

Just want to make sure it's going back together properly tonight...

Thanks,
Lance

[LSVLance]

Just in case someone else sees something I'm not...

In this diagram, #31 looks to be the copper tube I'm talking about.

http://www.crowleymarine.com/mercury-ou ... 56_250.cfm

It appears as if it is supposed to be just put into the hole in the bottom of the housing above it.

In this diagram, the white plastic tube (#13) appears to just be stuck into the top of the impeller housing

http://www.crowleymarine.com/mercury-ou ... 56_260.cfm

It doesn't look like there are any seals or bushings on either of them, just plug n play? anyone else concur?

[HandymanHerb]

Sorry I couldn't even find a part list for it on line, hope some one jumps in who knows soon

[LSVLance]

I've found the parts lists finally...

https://webapps.brunswick.com/literatur ... eSearch.do

Serial # is 1B517144

Model # 1175P73HY L PROXS

The parts I'm looking at are in the Gear Housing (drive shaft) and Driveshaft housing and Exhaust tube sections

I'm now seeing part #37 in the Driveshaft housing and Exhaust tube section which looks like it might be a bushing that drops in the plate assembly (#32) from the top...

It's just strange though, doesn't seem right that it's not some sort of tight fit, that copper pipe into the plate assembly

[curtiscapk]

Lance,

sorry I missed this this morning....


Mine is a 94 so probably slightly different. I did read ahead and had mine in gear... it took two of us with engine straight up. The tube was in the lower unit of mine and just went into housing above. I had some problems but after jiggling she locked right in. I am not sure with yours being in Neutral what that changes.

[LSVLance]

Thanks Craig, that makes me feel a little bit better.

I think since I left mine in neutral, I just need to move the flywheel to align the splines on the shaft since I can't turn it with the prop. Hopefully that gets the job done tonight.

[curtiscapk]

viewtopic.php?f=2&t=8709&hilit=lower+unit

check out these picks... does it look anything similar?

[LSVLance]

Eh, it's a little bit different than that...

I did re-read yoru thread though...which seal did you end up missing that keep it from pushing water at first?

That's what I'm most scared about since I just dropped it down and swapped the impeller out. I bought the whole impeller change kit and there's a whole bag full of parts there that I don't have any idea where they go...

[curtiscapk]

The black tube on top of the impeller housing had a seal on top and bottom I forgot one of them don't remember which one....

[LSVLance]

I got it back on... Ended up greasing up the top of the copper tube so it would stay in place in the base plate (it's in a seal up there pretty snugly) then putting a bit of grease on the white plastic tube to hold it on the copper tube, raising the lower unit into place with a floor jack while slowly guiding the white plastic tube into the impeller housing. Once I was sure all of that was lined up, I raised the LU up a bit more until I had to turn the flywheel a touch to engage the driveshaft splines then lastly raised it a touch more and lined up the shift shaft to guide it onto it's shaft.

Then there was a little pop and boom...it all fell right into place. I knew it when it happened that it was there.

Had one more little scare though, had the wife get up in the boat to shift into forward and reverse and nothing happened back at the lower unit, the shift shaft wasn't turning...nothing. I freaked out just a bit and then realized that just didn't make any sense. So I got up into the boat and realized that she pressed the button on the side of the controls disengaging the trans shifter. Once I corrected that, it shifted into forward and reverse just like it was supposed to.

Filled the LU back up with new gear oil and called it a night. We'll spiff it up a bit then she's ready to haul up to the lift the first nice day we get.

[HandymanHerb]

[MH Hawker]

Those water pump tubes can be a real mofo some times, I had to buy one of the scope camera`s to use in mine due to how it fits back in the upper socket and seal,

[curtiscapk]

Nice Lance!!! Yep when she clicks you know it!!!