Water pump leaking at the powerhead mercury 8 hp 1989

[Fxbeaver]

I'm having very little to no water coming out of the engine so i tested the water pump with a cordless drill in a water tub and it pump fine so I plug a water hose at the water exit when sending water in and looking into the leg i see water leaking where the water pipe from the water pump enters the powerhead and very little water coming out of the water pipe. Any advice please

 

[Texasmark]

How about some history. Engine usage, what you have done to it recently. Why a water problem now? Had any accidents, run in silt, weeds/moss/algae. Tube from water pump to block inlet reasonably straight? Got any gaskets missing. How did you test the water pump. Did you pop the top and have a look at the impeller?

 

[Fxbeaver]

I just bought the engine and i think the cooling system is not working properly the water goes on and of and the water temperature is really hot so i m assuming its not right. I did open the water pump and it looks ok nothing is missing. The test i did is removing the lower unit and connect a cordless drill to the shaft and sink the unit in a water tub while driving the shaft , the water was flowing out of the water pump. I also connected a garden hose to the pee hose on the motor and send the water while looking under the power head where the copper tube conect and saw water coming from there but maybe its normal?

How about some history. Engine usage, what you have done to it recently. Why a water problem now? Had any accidents, run in silt, weeds/moss/algae. Tube from water pump to block inlet reasonably straight? Got any gaskets missing. How did you test the water pump. Did you pop the top and have a look at the impeller?

 

[Texasmark]

Two things:

1. Per sales brochures in the 94 and 97 model years, 8 hp engines have an optional thermostat. The thermostat opening temp will be around 125-143F.....I'm told by others on here that the smaller engines use a cooler opening stat which is said to be around 125. Usually the pellet part of the stat has the opening temp stamped on the bottom. My larger engines ran 143. With the thermostat of a US domestic water heater set to Normal, the controlling temp is 140F for a reference as to how hot your water is. It's not uncommon for a stat to stick closed. On an 8 hp I don't know where it would be physically located, but from a performance standpoint, it obviously needs the pellet immersedin the crankcase water. Since it may also be optional on your engine, There is probably a small plate (size of a US quarter dollar coin, sitting somewhere around the crankcase, on the back, or top with a couple of screws holding in on. No stat would be possibly a flat plate and nothing under it whereas with would possibly be a bulge for water passage and the stat under it,

2. Just because you passed your test doesn't mean that your impeller is good to go. It is an optimum condition test if you ask me and the real world is usually much less than optimum conditions. Pop the cover and have a look. The blades should stick out straight like a wagon wheel's spokes or get a new impeller.

I'd check both and come back.

 

[Fxbeaver]

The blades stay bend when out of the case so i will change that. The thermostat explain why the water goes on and off thanks now i m less worried.

Two things:

1. Per sales brochures in the 94 and 97 model years, 8 hp engines have an optional thermostat. The thermostat opening temp will be around 125-143F.....I'm told by others on here that the smaller engines use a cooler opening stat which is said to be around 125. Usually the pellet part of the stat has the opening temp stamped on the bottom. My larger engines ran 143. With the thermostat of a US domestic water heater set to Normal, the controlling temp is 140F for a reference as to how hot your water is. It's not uncommon for a stat to stick closed. On an 8 hp I don't know where it would be physically located, but from a performance standpoint, it obviously needs the pellet immersedin the crankcase water. Since it may also be optional on your engine, There is probably a small plate (size of a US quarter dollar coin, sitting somewhere around the crankcase, on the back, or top with a couple of screws holding in on. No stat would be possibly a flat plate and nothing under it whereas with would possibly be a bulge for water passage and the stat under it,

2. Just because you passed your test doesn't mean that your impeller is good to go. It is an optimum condition test if you ask me and the real world is usually much less than optimum conditions. Pop the cover and have a look. The blades should stick out straight like a wagon wheel's spokes or get a new impeller.

I'd check both and come back.

 

[flyingscott]

Texasmark is correct there are 120 deg thermostats in those. The thermostat is located in the water jacket, follow the tattletale line up to the elbow and it is under that. You will see the thermostat housing as the elbow screws right into it. The tattle-tale stream should fluctuate a couple of times. If it does it continue to fluctuate you might have the 140 deg thermostat in there and that needs to be removed and the correct one installed.,Did the water pipe come out of the grommet under the powerhead look to make sure it is seated correctly.

 

[Texasmark]

Looks like we're rollin along on this!