Lower unit oil loss from res.

[MOBILEMERCMAN]

I would guess the Merc Manual is about 90 dollars. They should sell it to you. Some places are weird and may make a big deal out of it. I can give you the part number tomorrow if needed. I think the selocs are pretty much useless by comparison.

[Geronimo36]

Frank we agree again. I was first

You're on it again!!!!

If he's going to attempt to do it by himself he'll also need the seal driver. The yoke seal is pressed into place and it's pressed in slightly more than flush. If the seal is pressed in flush the face of the seal will rub up against the yoke and wear a hole thru it.

How do I know this? Well, many years ago a customer had a poker run planned and a day before the poker run he called and said there's oil in the bilge.. So I pull the drive and find it's the yoke seal. So I get it apart and come to find out we don't have any yoke's in stock and the merc dealership up the street (Freddie) doesn't have any yokes either...

So I call up the customer and let him know we can't get a yoke and he needs one and asks me to do whatever I can to get him running and we'll fix it on Monday.

So, I install the yoke seal slightly higher to attempt to allow the lip of the seal to ride on a clean part of the yoke... I put it together and pressure checked perfect.. Even went for a test run and it ran perfectly...

He called me half way thru the poker run saying the drive resevior is low again... so I'm like chit, WTF, everything checked out perfect.... So he runs the rest of the poker run and adds some oil at the card stops..

He got back from the run without any issue but on monday I pulled the drive and when to install the new yoke we had on order, only to realize the seal face had a hole worn thru it....

Lesson in all this... Don't try to get away with it, even if the customer asks you too!! And for the others, make sure you have the seal driver so it doesn't happen to you!

[2112]

I think the selocs are pretty much useless by comparison.

I think that is an understatement

Sent you another P/M BTW if you see this 1st.


I am glad we are finally getting the tech section rockin here on SOS!
.

[2112]

You're on it again!!!!

If he's going to attempt to do it by himself he'll also need the seal driver. The yoke seal is pressed into place and it's pressed in slightly more than flush. If the seal is pressed in flush the face of the seal will rub up against the yoke and wear a hole thru it.

Lesson in all this... Don't try to get away with it, even if the customer asks you too!! And for the others, make sure you have the seal driver so it doesn't happen to you!

Great info;

Here are pictures of a new yoke seal and anodized cover, front and back.

If I read you right, you meant the seal we see in the center of this unit needs to be less than flush?

.

[Geronimo36]

yeah, on the back part the cover (spanner wrench holes) the seal should be driven in slightly more than flush. the seal driver that's made for it drives it in, if I had to guess, roughly 20-30 thou more than flush. that's the new XR style cover, the older ones had a seperate plate and retainer nut along with a different seal.

[2112]

Boy, It appears to be flush now and that is straight from Mercury!
.

[ALM]

Yes, the yoke is the piece that holds the u joint and enters the drive housing. It is the seal that rides on the yoke that is likely to be your problem.

http://www.mercruiserparts.com/Show_...ift+Components

25 is the yoke 28 is the seal. Its all there

Thanks.. That's what I thought. I went to BAM site and looked at it also. I just wanted to be sure I understand the right terms. If it is my yoke seal, I won't do it mysefl. I will preassure check later today.
I might have to send you a lunch coupon.

[Geronimo36]

Boy, It appears to be flush now and that is straight from Mercury!
.

Jimmy will know more on this but it's possible the newer XR yoke seal doesn't drive in further anymore. It's a different seal and a different yoke than the older XR's with the smaller U-joints and the std. bravo. The design changed.

The larger u-joint assembly came out after I changed careers so I could be dating myself so let's see what Jimmy says about the new ones.

[PARADOX]

Good info.

Can I pressure check the outdrive while in place? or it has to be removed? What pressure should I put on to test. I have a leak down test kit, that I think I can use.
THX
P

[Geronimo36]

Can't pressure check on the boat unless you pinch or plug the drive resevior hose which I never recommned...

Merc has a specific pressure/suction test proceedure which I vaguely remember the exact details. I seem think it was something like 10-12 psi for 10 minutes with a minimum % drop over time (1-2 psi max drop)???? (I'd have to double check the book for exact figures). I've found they're either good or bad, not so much inbetween.

Basically, you put in 10-12 psi and if it starts dropping off you need to re-seal... Most of the time the leak is from pressure not suction but test both to be sure.

[MOBILEMERCMAN]

Jimmy will know more on this but it's possible the newer XR yoke seal doesn't drive in further anymore. It's a different seal and a different yoke than the older XR's with the smaller U-joints and the std. bravo. The design changed.

The larger u-joint assembly came out after I changed careers so I could be dating myself so let's see what Jimmy says about the new ones.

I can't comment on the newest. The driver number is 91-813683T and as Frank mentioned it positions the seal in about .020.

On the early standard Bravos flush was OK. You can position them further in once or twice to avoid the ring groove that forms.

Its the X XR XZ that are different. They carry the seal in the cover nut. The standard the seal rides in a spacer piece.

[MOBILEMERCMAN]

Merc has a specific pressure/suction test proceedure which I vaguely remember the exact details. I seem think it was something like 10-12 psi for 10 minutes with a minimum % drop over time (1-2 psi max drop)???? (I'd have to double check the book for exact figures). I've found they're either good or bad, not so much inbetween.

Basically, you put in 10-12 psi and if it starts dropping off you need to re-seal... Most of the time the leak is from pressure not suction but test both to be sure.

I test to 14 lbs. with no drop. If it sits over night it may drop from cooling other than that I seek no drop and prefer to let sit for 30 minutes. Sometimes that is not practical but that is my preference.

[2112]

I would guess the Merc Manual is about 90 dollars. They should sell it to you. Some places are weird and may make a big deal out of it. I can give you the part number tomorrow if needed. I think the selocs are pretty much useless by comparison.

Bought it today.

Wow, what an extremely nice shop manual. The Seloc is going straight into the recycle bin.

I took my drive down to have the upper shaft assembly replaced. They said it is about a 1 hour job barring any unforeseen problems.

.

[ALM]

Mobil man. You got lunch comming. I just tested the drive. Put in about 12 - 14 pounds and I heared air coming at the seal.
I got to take this to get it fixed.

[MOBILEMERCMAN]

Glad I could help....

That's what we do here. Help each other.

[Geronimo36]

Mobil man. You got lunch comming. I just tested the drive. Put in about 12 - 14 pounds and I heared air coming at the seal.
I got to take this to get it fixed.

This is a good time to reseal the complete upper. Next year you might pull the drive off and find oil in the shift cable cavity, coming from the shift shaft seal. Also a good time to check all the gears/bearings....

The labor to dissasemble the upper gear/yoke and replace the yoke seal (possibly even a new yoke) combined with the cost of a single seal vs. a seal kit is somewhat close so I'd just do the whole upper while you have it off and apart.

[ALM]

Great. thanks. more $hit to deal with?
Merc men needs to bring his tools to the Keys. I bring the drive.

[MOBILEMERCMAN]

Sorry Alex, I went the last couple years. I will not be going this year. Resealing is basic work any dealer should be able to turn it over for you quick.