1967 OMC outdrive waterpump maint.

[Alws55]

I have changed many impellers on old outboards over the years, but this OD has me puzzeled. I have a seloc manual, I have the lower unit off the upper gearcase and the manuals telling me that the pump is in the lower end of the upper gearcase which does not look anything like the pics in the manual. There is a cover on the top end of the lower unit that is very similar to a standard outboard pump housing but the water inlet tube comes in above the housing where the driveshaft meets the lowerunit shaft.
The guts on the bottom of the upper gearcase protrude 3" or so out of the housing but in the pic they are slighly recessed, both have 4 bolts that are to be removed to drop the pump out. thanks for any help..

 

[Lyndy]

Re: 1967 OMC outdrive waterpump maint.

There are typically two types of Outdrives from 67-77, High Profile and Low Profile. Sounds like you have the High Profile like mine. If you had an OEM OMC Service Manual for your year model the picture would have been different. The High Profile has a longer shaft hence the guts stick down about 3 Inches below the bottom of the Upper. The Low Profile is almost from with the bottom of the Upper. Directions to remove are similar but not exact for both. I have included pictures of the enclosures so you can compare.

High Profile

Diagram of Low Profile Item #51 Will give you a good idea of the height differences in the Bearing Casings which the Pump Housings attach to.

Hope this helps

 

[Alws55]

Re: 1967 OMC outdrive waterpump maint.

Thank you Lundy....upon inspecting the housing between the gear & water pump , there is a 3/8" hole in the sidewall that is on the inner wall. Is this designed this way? The inside is also very pitted there is a spot as large as a quarter, I'm thinking of using one of those 2 part metal patches to fill this in. I imagine this part alone would be hard to find. Would a upper GC from a 1978 175hp fit this unit?

http://cgi.ebay.com/ebaymotors/ws/e...m=200158967889&ssPageName=STRK:MEWA:IT&ih=010

 

[Lyndy]

Re: 1967 OMC outdrive waterpump maint.

The picture indicates an Upper GC that is 1977 or older. My own Upper GC came with a Gear Set from a Unit in the early 80's. I do not believe the Unit you are looking at on Ebay is compatible. It appears to be a Low profile and I believe the Upper and Lower Drive Shaft are different. You will need to find a Upper GC from a High Profile Drive. If some one knows differently I am sure they will respond

 

[Alws55]

Re: 1967 OMC outdrive waterpump maint.

Thanks again for your responses....how about the 3/8" hole in the of the unit you have pictured? It would be part #51, the water rising up in the cooling system would blow thru into the upper GC housing {still sealed from the gears}, is this an added flow up to the motor. Its roughly 2" up from the impeller housing and inbetween the 2 oval ports that take the water up to the motor.If a pic is needed I'l take one and post.

 

[Alws55]

Re: 1967 OMC outdrive waterpump maint.

I found out today that the hole is for gear oil to pass thru to the bearings inside that housing.