transom seal teardown - pics

[whiskeyRichard]

At the advice of this forum, I am replacing all my bellows, lower shift cable, gimbal bearing, impeller and going through the engine alignment procedure......I bought the alignment toolkit with all the cool extra tools in it as well. I purchased all OEM Mercruiser parts where I could.

There was water coming in.....after removal it is obvious it was coming from the town u-joint bellows.

Attached are a couple pictures from my boat after removing the drive. The one of the impeller is interesting.

Questions are:

1) Should I replace the U-joints? they feel and move nice and have grease fittings, but they look like hell

2) There is a rubber o-ring at the top of the splined shaft coming out of the lower unit (pic)....I think I read on here that when I re-assemble my drive that I am supposed to leave that off. Did I make that up, or is that correct?

3) The first couple drops of oil that came out of the lower unit looked suspicious, but after that, the oil looked good. Should I reseal and pressure test the outdrive as well?

Thanks for the help. I live in the middle of nowhere and without the help of a group like this, I would be beating my head against the wall.

I also attached a picture of my boat. It a 1980 25 foot SKV with a Mercruiser 260.

Thanks again,
wR

 

[achris]

1) Should I replace the U-joints? they feel and move nice and have grease fittings, but they look like hell

That much water, I'd replace them. Also that gimbal bearing is not long for this world, replace it too.

2) There is a rubber o-ring at the top of the splined shaft coming out of the lower unit (pic)....I think I read on here that when I re-assemble my drive that I am supposed to leave that off. Did I make that up, or is that correct?

Yep, get rid of that 'o' ring. nothing but trouble... I'd also replace the seal in the bottom of the top housing. Watch my video on replacing the impeller and you see me flick an old one out. Later and replacement drive shafts no longer have the groove there. So that's what Merc thinks of the 'O' ring.

3) The first couple drops of oil that came out of the lower unit looked suspicious, but after that, the oil looked good. Should I reseal and pressure test the outdrive as well?

Possibly just a few drops stuck to the outside of the plug, between the top and the seal. When you get done replacing the impeller and putting the drive back together, pressure and vacuum test it.

Thanks for the help. I live in the middle of nowhere and without the help of a group like this, I would be beating my head against the wall.

I also attached a picture of my boat. It a 1980 25 foot SKV with a Mercruiser 260.

Cool ride.

Chris.........

 

[harringtondav]

Cool ride.

Chris.........

Very.

 

[Scott Danforth]

if you had to put the drive on to make an escape right now because the world was blowing up..... maybe use the u-joints.

however the u-joints and shaft need some serious love. Agree with Chris, change the gimbal bearing as well......and the input shaft seal.

 

[whiskeyRichard]

if you had to put the drive on to make an escape right now because the world was blowing up..... maybe use the u-joints.

however the u-joints and shaft need some serious love. Agree with Chris, change the gimbal bearing as well......and the input shaft seal.

I know what to do regarding the u-joints, but what does the shaft need......just clean it up with an emery cloth? I assume the input shaft seal refers to the 2 o-rings on the shaft in the attached picture?

Thanks!!
wR

 

[Scott Danforth]

I personally would replace the whole shaft - rust never sleaps

at a minimum you need to glass bead the cardan carrier as well as both shaft ends, and then polish the seal area to between 8 and 16 rms.

once you pull the u-joint shaft out of the upper gear carrier, you can then replace the input shaft seals.

see items 16-20

 

[whiskeyRichard]

ok, thanks for the diagram.

Funny, when I bought this boat, the guy told me it was 'lake ready'......maybe he meant bottom of the lake ready. lol

I see I can purchase an entire replacement u-joint assembly for just under $300. Once I add in those other parts, I am wondering is I just shouldn't replace the entire upper with a reman unit.....what do you think. The lower unit on my drive is brand new.

Can I borrow some money?

Thanks again,
wR

 

[Scott Danforth]

with any new to you used boat, take what ever the guy said to you to sell you the boat as a lie.

you need to do all the maintenance on the boat, motor, drive and trailer

up to you if you want to replace the whole upper. its your money.

 

[whiskeyRichard]

By the way, are those diagrams coming from a repair manual that is available for download or is that a purchase item?

 

[whiskeyRichard]

Funny thing, the first time I put the boat in the water, the bunks on the trailer all floated away. LOL. I had to jump in and grab them and then call a friend to fix it in the parking lot for me while my wife were out on the lake.

I am glad it is fall and not spring I guess.

 

[Scott Danforth]

its an image off of google. there literally are about a thousand on-line parts-sellers for mercruiser parts including i-Boats