1994 mercury 25 hp not "peeing"

Seantracker

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Jun 30, 2011
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I have a 94 merc. 25 hp 2 stroke that isnt peeing water at idle. If i put it in gear it will pee water real good, once i take it out of gear it stops and just sputters out. Could this be a water pump issue or is this normal. I have it in a barrel, no ears.

Also can someone tell me how to "de-code" my serial number
0g067534

thanks!
 

hotrod53

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Re: 1994 mercury 25 hp not "peeing"

The peeing is not normal as I know it, does it pee in neutral when you go into a fast idle? The impeller spins on the driveshaft that turns all of the time, it should make no difference if its in gear or not. I would drop the LU. I would guess and say that your impeller is bad or the key is goofed up on the impeller.

I have a couple of decoders but they are all for older motors.
 

Seantracker

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Re: 1994 mercury 25 hp not "peeing"

It will pump water at fast idle sometimes, it's intermitent. When I first start it it blows out what appears to be exhaust??????? Sometimes it will pee and sometimes it won't.
 

Seantracker

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Re: 1994 mercury 25 hp not "peeing"

Replaced the water pump, not luck, still not peeing water like it should. The kit included a few washers and 2 o-rings that weren't on my old pump and I can't figure out where they go.
On the copper pick up tube, is there an o-ring at the top where it seals into the head? LOST
I can't find a good diagram that shows the copper tube either.
It will pump water but then stops, then if I put it on high idle it will start pumping again but stops, almost like it's losing "prime"
There are 2 holes, one on either side of the front mounting bolts for the lower unit that are pushing out exhaust(running in a barrel) are these low idle ports?
HELP PLEASE!!!
 

Texasmark

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Re: 1994 mercury 25 hp not "peeing"

Gonna say yes on the oring at the top of the copper tube.....you have to have some sort of seal up there as you have to force water through the powerhead.

I think in some engines the other oring is mounted on the driveshaft just above the water pump. I guess it acts as a slinger and keeps exhaust off the top of the pump/seal... only saw it one one engine and don't remember which one.

On the gas and the top two holes, therein lies your answer. All the water pickup holes on the sides of the lower unit must be submerged. Any that are exposed to air or very near the surface will allow the water pump to suck air (easier than sucking water) and you will get the problems you mentioned.

You are apparently running the engine in a barrel without enough water in it to cover the holes. Putting the engine in gear agitates and circulates the water and enough covers the holes off and on giving the results you mentioned. I realize that when you put it in gear, propwash splashes a lot out so to keep the problem from happening, you need to hook a hose up and if you leave it idle too long in the drum the water will get hot.

Actually, you need to have the water level up above the water pump for it to act correctly. If you were on a boat and on plane, there would be enough ram water forced into the impeller to keep it working properly even though the water level was lower than the pump. And if you were in the boat and at idle, there would be adequate water over the pump/holes to allow the pump to function properly. BTDT Learned the error of my ways as a young lad with a little 10 hp Scott Atwater.

Mark
 

Seantracker

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Re: 1994 mercury 25 hp not "peeing"

The holes I am refering to are on the lower side of the "fin" where the mounting bolts(4) go into the shaft to hold the lower unit on, they ARE under water. I dont think the barrell has anything to do with it, it's FULL.
I wonder if i have a leak in a power head?
 

Seantracker

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Re: 1994 mercury 25 hp not "peeing"

Just thought of something else..where the shift linkage goes out of the back of lower unit isn't sealed. Is it supposed to be, this is not under water and I see water coming out of it.
 

jerrydempsey

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Re: 1994 mercury 25 hp not "peeing"

put in barrel and let idle take air hose and spray air in peehole should fix it!
 

Seantracker

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Re: 1994 mercury 25 hp not "peeing"

Turned out to be a bad T-stat. NEW PROBLEM.....when I removed the cover to get to the tstat, the bolts broke off inside the motor
Do they make helicoils that small??????????????
 
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