Outboard Water Pump Question...

Jay Anglin

Jay Anglin

Well-known member
I just replaced the entire water pump on my '93 Mariner 40. When I tested it the stream of water coming from the "pisser" was solid and heavy which is a good thing. I throttled up to a good rev and noticed water bubbling out of the vents top center screen. I would assume that this is because at the increased rate of uptake as the shaft rotates faster the amount of water going into the block reaches critical volume and then the excess gets dumped. But maybe this is wishful thinking? I plan on replacing all the seals in the lower as a preventative measure in the future but I'm pretty confident that the pump is sealed well at the base etc.
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Any comments?
 
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Have you been burping it? I hear that such a condition can be caused by inadequate burping.

Glad I could help.

T
 
Do I use a freakin' hammer or a pipe wrench for that?
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I'm not sure, I've always burped since being enlightened, so I haven't had that problem. Seems like a bad case, you are going to need a big wrench or hammer, whichever you choose.

T
 
No tools needed for burping..just disconnect the water supply and run it wide open till no water comes out. Those are drain holes aren't they? They drain the midsection so water doesn't sit in there and freeze. Don't rev it up on a hose! Stick it on a boat and go to the lake. If you think your lower is leaking, take the lower drain screw out and see if water comes out before oil..or if the oil is a milkshake.
 
You also have your earmuffs on backwards.
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It don't matter when the prop is off. Since I trimmed it down it was difficult to put them on stylishly...like I said-don't matter anyways.

You can just make out that 25lb lead pyramid and the 35lb steel pyrimid in back. Like a big hand, I figured on the 35lber and just dropped it on the cowling...now the flywheel doesn't seem to spin right without getting hung up in the fiberglass shards.
 
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Okay Lee...that's what a figured but I just don't recall seeing water come out of those vents and maybe that's because the pump is working so well? Since I've never run it at "high rev" on the ears I've probably never noticed this-if it had been in the water or in a tub you wouldn't be able to see the water coming out of those vents I'd assume.

Hey, I didn't "floor it" or anything on the hose. I usually use a tub of water but this was just to check the pump. Yes, the lower unit gear lube was full of water but I'm pretty sure it was the shitty little gaskets on the two plugs leaking. I replaced them.
 
Jay,

Might grab the owners manual. Some motor brands recommend taping up the unused intake vents. Also, I don't think you're supposed to give them too much gas when on the muffs.

Good luck.

Charlie
 
Jay,

Might grab the owners manual. Some motor brands recommend taping up the unused intake vents. Also, I don't think you're supposed to give them too much gas when on the muffs.

Good luck.

Charlie
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I need to get me one of them manual thingies....maybe a Clymer eh? I guess I've never understood why you can't rev them a little on the muffs. It's getting great water flow and not red-lining the motor. It isn't in gear other than when I check the R-N-F at idle to make sure I had shifter squared away.
 
My only guess is that the water volume from the garden hose doesn't keep up with the impeller pumping volume at high rpms?

Mine was in the factory owners manual. It has intakes up under the cavitation plate and it said to cover them with duct tape when using muffs. Kind of weird I think, but who am I to argue with the manufacturer.
 
Always replace the little washers when changing the LU oil....I don't bit should. I was just reading where that is the 90% cause of water in the lower. Get some new washers, drain the lower and refill. Run it a while and see if the oil got milky.
 
I'm pretty sure that's it Lee-it was the typical milky color you see with lots of viscosity so I don't think it's a high volume leak. I already changed them but I haven't had a chance to run it in the water. I was just concerned with that water pouring out of the vents.

Charlie...I think that's it too. If I could put any more water into the system I think it would have exploded! The broken stream in the left of the photo is the stream about 8 feet away from the stern...it was shooting so far out that I had to use the zoom so I would get the camera wet from all the water and exhaust spraying all over the place.
 
The reason for not taching up an outboard out of water is.....it can easily cause a runaway..in two stroke lingo that is where the motor self ignites the fuel with no regulation and it just goes till the pistons freeze up or come out the side of the block. A hot piece of carbon inside the head can do it. There is no muffler on these to give back pressure, A runaway can't be stopped by a kill switch either since it isn't the plugs firing the gas...have you ever heard a 15,000 rpm 2 stroke? I think the taping of the vents is ONLY for running on muffs so you don't suck air into the system...the muffs kinda take the place of the water pump as the water is under pressure shooting into the pump through the pick ups so it shouldn't spray as far when pumping itself.
 
Wow...that sounds exciting Lee! Now I know. Bet if I dropped that 35lb steel anchor on the top of the upper it'd burp it into stopping!
 
You would probably catch 35 lbs right between the eyes.....and your last words would probably be a burp..or gurgle..Get a can of Seafoam a 1 gallon tank of premix..dump the sea foam in and idle it for 15 or 20 minutes...then let it sit for an hour or so..then take it out and run the crap out of it with the rest of the tank. This will clean the carbon out of your head and rings and I find the motor starts and idles like a new one.
 
I do that a couple times of year....I think it was on your recomendation here one time. I love Sea Foam...I use it in the Durango, the lawn mower, the outboards. It also thins bar chain oil to winter grade nicely too. Like maybe a capful per refill of standard bar chain.

Its oil injected so I don't run pre-mix. Are you saying run pre-mix anyway to treat the motor? My buddy Dan always put a little oil in his tanks for his '89 injected Mariner 115 and swears it runs better. Same 2/4 ignition as mine roughly. He swears by it. His boat and motor are showroom quality...it's an '89 Pro Caft bass boat. He gets lots of looks from boat guys and the motor "runs like a scalded dog" as he puts it.
 
I guess I would still use pre mix for that little amount...better safe than sorry. That Sea foam is a miracle product. I ran it for about 10 minutes before I re built my 35 Navy Seal motor and that thing was clean as a whistle inside. Before I ran it, I looked in the plug holes and the tops of the pistons were black and caked. I ran it in the Merc 9.8 I got from Staudacher and it made it run like new...before that it ran ALMOST like new..heh heh heh.
 
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