OMC Stringer upper gearcase re-seal?

[Chad Flaugher]

1974 OMC 302 Ford 190hp Stringer Outdrive: I've been getting a small amount of water mixing with the gear oil in the upper gearcase. I keep fresh clean oil every time we go out, but in October I want to re-seal the upper gearcase before my luck runs out. Anybody done this before? The boat shop wants $200 including the seal kit, and that's if I bring him JUST the gearcase tore down off the boat. (Which is no big deal) That seems like an okay deal, but if somebody can talk me into doing it myself, I might go that way. I do have a shop manual, but seems a bit intimidating even though I have better than average mechanical skills. Your 2 cents would be much appreciated!

 

[southkogs]

... for $200 I'd be takin' it in myself I've never had to reseal one and don't know what it takes.

 

[Chad Flaugher]

Thanks for the input!

 

[VE8EV]

The "proper" way to verify the seals is by a pressure test, basically a tee adapter with a pressure gauge you can screw into the lower oil plug and put 5-10 lbs of pressure and see where the oil leaks out (if anywhere). That said, one of the "usual suspects" is the o-ring under the exhaust housing cover, OMC 0310327. It's quick and easy to change and only costs a couple of bucks. I would always replace that one first before embarking on a full re-seal job.

Watch out for the two little washers and the spring under the oil level dipstick when the cover comes off.
Edit: and put some blocking under the skeg so the lower unit doesn't fall off when you take out the cover bolts!

 

[Chad Flaugher]

Ah! I know about the o-ring atop the pedestal under the exhaust cover, as it appears to be fine, and the cover went on snug. There are a couple seals that are suspect at both ends of the upper gearcase. I like the pressure check idea! It's all back together now, awaiting a test run. With only 4-5 weeks left in the boating season here in Colorado, the chance to really dig into it is just around the corner. Thanks for the advise guys!