Intermediate Housing Question

[Stringer Guy]

I have a 79 Seaswirl with the chevy 2.5 engine (110 HP) and the OMC Stringer 400 sterndrive. Does anyone use normal 10W30 oil in their intermediate housing? I have 80W90 gear oil in now like to book says but a local mechanic says I should use the motor oil. My engine overheats with power but runs fine at idle and a little above. I don't want to blow anything after my rebuild. Any info is appreciated.

 

[Howard Sterndrive]

80W90 in the intermediate. What's in there is a shaft and two tapered roller bearings that rotate at engine speed. Engine oil wouldn't be a good thing.

If your engine overheats above 3000 rpm, your impeller is likely sucking exhaust gases through a dry swivel bearing. Grease the swivel bearing. The zerk is through a hole on the nose of the outdrive facing forward. You need a grease gun with a smallish tip. Give it 6 good pumps of grease twice a season.

 

[Stringer Guy]

Thanks, I finally got it out and tested it at speed. Still overheats. Have you ever heard of using and electric pump in the water line? I'm at a loss here.

 

[Howard Sterndrive]

did you grease the swivel as was suggested?

 

[Stringer Guy]

Sure Did. Can't really figure it out. been this way after the rebuild and new impeller.

 

[Stringer Guy]

Do you think I should connect a water pressure sensor? Does the pressure continually rise relative to the impeller RPM?

 

[Howard Sterndrive]

it does but if the overheat is only at higher rpm, the usual suspect is exhaust getting into the water flow. You can replace a section of the hose with clear hose and go for a run to watch for bubbles. (and you'll get a look at the flow)
This vid is of a Mercruiser, but same idea:
https://www.youtube.com/watch?v=shmjznMxmpw

watch at 1 minute as he slows down and the bubbles disappear

if that's not the issue, you could have clogged exhaust manifold not letting enough hot water out

 

[Stringer Guy]

Hey Thanks,

I found a little blockage and fixed that. (I'm not sure you want to know.) It still gets hot but much slower. There wasn't any bubbles when I used the clear hose. This is the 1st improvement in a couple of years.

I noticed a plug in a port on the circulating pump. Have you heard of anyone removing the plug and attaching it to the intake flow?

 

[Howard Sterndrive]

have you verified the accuracy of the gauge with another gauge, infrared or even your hand?

If so, and the manifold is original 1979, it would probably be worth changing out. They are really designed to last 10 years and yours would be 35 if original.

Hard to imagine you would need more water flow. The raw water impeller in your drive is the same as the one in a 260HP OMC sterndrive, and yours has less than 50% of that heat to get rid of.

 

[Stringer Guy]

Well, I finally got it working right. Had it out a couple of days ago and it ran no higher the 170 degrees consistently. I really have to thank you because it might have taken another 3 years before I got around to questioning the water flow. You da Man! :joyous:

 

[Rich Novak]

What did you do to fix it.

 

[Stringer Guy]

Well, I had left the flush attachment on the manifold hose ever since I started the engine and flushed it. I knew it was getting water, but I never asked if it was getting enough water. Turns out that was the question. I replaced the hose straight with an automotive hater hose and the problem decreased, it climbed to about 185 degrees. Then I got some marine water hose, which is about twice as thick and didn't compress any in the bend, and that was it. I think I would've spent another few years diagnosing and troubleshooting if you hadn't pointed me in this direction. Thanks again