1972 OMC Intermediate housing Overhaul and Function

[lanthony2020]

Hello, I am restoring a 1972 Land N Sea houseboat. It came with two 1972 OMC Stringer drives, GUFM-10S. I have purchased new balls gears and shafts including new bearings, gaskets, etc.. Not together yet. I have hydraulic steering. The tilt motors are also new.

Question: The top of the intermediate housing, there is a cover bolted down, I cannot seem to get the screws loose to take the entire unit apart. What important function other than the shaft, tilt motor, steering, does the intermediate serve? What is inside here that I need to pay attention to? I know the exhaust runs through this as well? Anyone know? Is it necessary to take this all apart?

Thank you in advance.

lanthony

 

[mercedglen]

Well, I have a 1972 Sea Swirl UVFM 10c so we have something in common. What I have discovered is that 1972 there was an upgrade to the Ball Gears except that there some years that use the old style pressed on only Ball Gears. I am replacing mine as well. I have found out that I can replace the shaft in the upper side with a newer version which will use the new style ball gears.

the intermediate side is the part I am working on now. Yesterday I unbolted the retainer that holds the shaft into the intermediate. The Ball Gear is supposedly very difficult to remove, NOT.....In the process of trying to get shaft removed, the shaft is attached to the coupler on the flywheel, the Ball Gear came off.

this present two problems maybe. the Ball Gear is multi-splined. Different from what I thought it should look like. There is not nut which I expected but I think inside the shaft there a threads which is confusing as well. I found the same situation on the upper side. So now I have the Ball Gear off but the shaft is still in the coupler. I think because it may never have been removed it is frozen in the coupler. Hence I may have top pull the intermediate to get at it. I want the shaft out so I can determine if I can upgrade this part as well. If I have to pull the intermediate I will also have to replace the seal so I am doing pretty much a rebuild of anything that is suspect.

I don't know if there is an easy way to pull the shaft without removing the intermediate. I usually go to Marine Engine but so far there has been no response. I saw your questions and thought I might let you know I am doing the same things myself. TC Electronics Marine is very good as a resource too. Let me know how it goes.

 

[southkogs]

Welcome aboard lanthony:

I don't know the exact answer to all of your questions, but I can answer a few:

Question: The top of the intermediate housing, there is a cover bolted down, I cannot seem to get the screws loose to take the entire unit apart.

I'm assuming you're actually talking about the upper gear case. The intermediate is the part that runs from the ball gears to the engine block (marries up where a cars transmission typically would). The upper gear case is the top of the stern drive with the cap (see image):

What important function other than the shaft, tilt motor, steering, does the intermediate serve? What is inside here that I need to pay attention to? I know the exhaust runs through this as well? Anyone know? Is it necessary to take this all apart?

If my surmise is correct, you're fighting with the bolts of part 13 in that image. The upper gear case is pretty simple, but I'm too big a chicken to tear one apart so I've never loosened those bolts. If you've got the upper off of the drive, and you can turn the ball gear by hand or with a wrench then you can assume (reasonably safely) that you don't need to go breaking into that unit.

No exhaust passes through this case, and the tilt motor doesn't connect to anything inside this case. I'm fairly sure you can replace the ball gear without cracking the gear case open (though I'm not positive on that). If it turns free, I would replace your impeller at the base of the unit and close it all back up.

The intermediate housing is the part that marries up to the engine and sticks out through the keyhole in the transom. The tilt motor connects up to the port side of that housing inside the transom, and nearly everything passes through that unit.

Hydraulic steering is something I wasn't aware they had on the '72s. I have the "pass-through-the-transom-pain-in-the-neck" steering, and I know of the true course steering that connects to the upper. Maybe post a picture of your steering.

Do you have a good shop manual? And have you had these systems running at all?

 

[lanthony2020]

I am talking about the intermediate. Mercedglen, go on Youtube and and query OMC Stringer Intermediate and there is a good U-tube of how to pull this. I also have a new extra drive shaft.

Southkogs: I have external type hyrdolic steering (custom for houseboat).

I am wondering what else the intermediate does? The top (inside the boat) has a plate that is screwed on top. Goes into a cavity of some sort? What is this? Is there any necessary maintenance here or can I just put my new drive shaft in and call it a day?

lanthony

 

[lanthony2020]

I see now it is the "oil reservoir." Anything to worry about here?

lanthony

 

[southkogs]

AHHH ... I think I see what you're lookin' at now: There should be a large screw head on the outside of the intermediate (just behind the transom). That's your lube fill. It's also your lube drain ... you'll need a pump of some kind. You want to change that lube out like you do your upper and lower gear lube ( I do mine about twice per year).

BTW - if you don't already know, your lower needs Type C for the electric shift.

 

[wrench 3]

I ran an electric shift stringer for ten years. I'd check the oil in the intermediate housing for signs of water each fall. It was always OK, so it only got changed when I changed the ball gears.
BTW there's no need to remove that plate.

Mercedglen: If the outer end of your intermediate shaft has threads in it, I'd try a slide hammer on it before removing the housing.

 

[lanthony2020]

Thanks Wrench!

 

[Boomyal]

Thanks Wrench!

You did not say what motor you have. However, the ball gear shaft is probably rusted to the coupler on the flywheel. The coupler had an oring inside it to help keep grease on the splines As the coupler is hard bolted to the flywheel, with no rubber buffer, the splines on the shaft and coupler take a horrible hammering, especially at idle.. Through the years this seal was no longer effective and as the grease dried up and shrunk, rust took over. In 1978 when they went to the Hydro-Mechanical drive they increased the size of the splines to make them beefier. Depending on what engine you have, you might be able to get a later coupler and shaft with the larger splines.

I pulled the 302 on my '75 back in about 2005. The fine splined shaft and coupler were significantly compromised. Because the 302 was still in use when they went to the hydro mechanical drive, I was able to get a larger splined coupler and ball gear shaft.

 

[lanthony2020]

Just getting back to this after four surgeries. I have the GUFM 10s 1972 Intermediate. Mine is not shimmed per say, it has a spacer??? Anyone familiar. I found 2 NOS. Part# 0316488. Seems easier than shimming but probably not as good?

THX
Lex

 

[wrench 3]

Wow, I hope your health is improving.
I can't get that 0316488 to come up anywhere. What is it?

 

[lanthony2020]

Instead of a using shims, the GUFM-10S 120HP uses a spacer, one size fits all. Wondering if shimming would be better like the GUFM-10C? Easier for me to just use the OEM spacer???

Lex

 

[wrench 3]

The "C" uses a different bearing than the "S". They used that same bearing with a shimmed set up in the newer drives. I don't know what the advantage was but apparently they decided that it was the best set up to go forward with.