Water Pickup on OMC 800?

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Mahoney

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This is kind of coinciding with another post I have, but a little different topic. I have the manual for this 1974 OMC (800 I believe) sterndrive. In the manual it shows 2 different flushing proceedures for the unit. In one(which I have been doing) you connect a hose directly to the pivot cap on the starbord side where the upper housing meets the intermediate housing.<br /><br />In the other proceedure listed it shows using muffs on the lower unit. Well, my lower unit has no water inlets for muffs as I can see, only 2 small holes on either side of the upperhousing about in the middle of the casing. When I hooked muffs up to those holes I didnt get any coolant circulation through the engine when running, when I hooked back up to the pivot cap I was fine.<br /><br />Any input on this would be appreciated.
 

John Smith

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Re: Water Pickup on OMC 800?

Mah<br /> In you type of out drive you only connect water thru pivot cap. Do not connect water by use muffs to those hole and run the engine, you will ruin you water pump in no time.
 

keelhauled

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Re: Water Pickup on OMC 800?

Unless I'm totally confused (which does happen!)...<br /><br />It has to have water intakes... where would it get water while under way? The intakes are directly above the "bullet" of the lower gear case. They are a series of holes on each side of the drive.<br /><br />You can run an 800 on muffs provided you supply the volume of water required to cool the engine. If you couldn't, I would have replaced a whole lot of pumps in my 800. This is true for almost any outdrive including OMC stringers, cobras, mercruisers and the like. As long as the pump has sufficient water, does it really matter where it comes from?<br /><br />Of course, if you're not comfortable running it on muffs, don't do it. It's your investment.<br /><br />We've run our chris-craft volvo/thermocon develvo system on muffs every year, and it's raw water pump is clear up on the front of the engine. Like I said, as long as it has sufficient water to the pump, it doesn't care where it's from.<br /><br />If water is not coming out of the exhaust (underneath where the anode is) and out of the ball gear 'pee-hole', you're in trouble!<br /><br />The single most important thing to remember, whatever you do, is not to ever run the engine, even for just a few seconds, with no water supply. This will without a doubt damage the pump impeller.
 

Mahoney

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Re: Water Pickup on OMC 800?

Crap, I am afraid I might have done that, but I have no way of knowing. I have the water pump repair kit coming already so thats fine, I am going to swing it down tot the lake and back it in with the trailer and run it with the outdrive in the water to see if the pump is operating properly, if not, take her home and wait for part.
 

Mahoney

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Re: Water Pickup on OMC 800?

Aperantly the water inlet on this sterndrive is a hole facing down on the underside of the upper housing about the size of a gardenhose with a screen on it. I guess with this setup there is no way to tell if I damaged the impeller unless I back the drive into the water and try it. It pumps water fine when hose is hooked up to pivot cap.
 

keelhauled

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Re: Water Pickup on OMC 800?

wait wait wait wait... duh.. i spoke before i thought... you have a '74... high profile drive... it's different than that which I am referring to. The first generation stringers were an odd duck and most standard rules do not apply. I apologize if I mislead you.<br /><br />Regardless, you'll have to put a pump in it when you do the seal job... so I wouldn't sweat it. I wouldn't run it with water in the gear lube anyway.
 

keelhauled

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Re: Water Pickup on OMC 800?

Don't panic... wait for parts, fix it right, then take it out and enjoy it.
 

Mahoney

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Re: Water Pickup on OMC 800?

Yah I replaced the gear lube again and hooked up on the pivot and ran with a lot lower hose pressure so water wasn't forced all over the place and the temp of the engine ran fine at 155 degrees. I placed into forward gear @ about 800rpm and let it run easy for a couple minutes and shut down and checked the gear lube again. When taking off the top cap there wa a vacuum sound(which is good) and the lube looked ok.<br /><br />I plan on trailering it to the ramp tomorrow(only about 4 miles and running it submerged to see if all is ok and check the gear lube again. Worst case I see a little water in there, back it out, clean out the bilge good while I am on a good incline and work on it next week.
 

KaGee

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Re: Water Pickup on OMC 800?

Do you have true coarse steering?<br /><br />One thing I learned was that the bushng/seals on the steering gear shaft was a source for water intrusion in a large percentage of uppers with water problems. You get the seals with the kit, but the brass bushing is extra.
 

Mahoney

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Re: Water Pickup on OMC 800?

Not sure what true coars steering is, but I am pretty sure I don't have it, the shaft for the steering comes right out of the starbord side transom and connects with bolts to the OUTSIDE of the upper gearcase. I plan on taking some good pics today so that I get some more bang for my buck out of these posts.
 
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