leaking lower unit?

[grsmnky1]

hello I have a 1987 force 125 b recently I snapped my driveshaft, it was a single solid shaft that snapped right below the water pump. A shop sold me a 1992 2 piece driveshaft c model dual exhaust that looked like it would work. The twist is the water pump on this unit does not have the white connector that fits over the water tube on the midleg. I bought a seal kit for the lower unit I purchased and it had a rubber collar type seal that is slightly larger than my tube. After installation(some dremmeling required on a arch above the water pump) I hooked it to the ears and noticed water coming from 2 very small holes on the outside of my lower unit one above the vent screw one on the opposite side.
My old lower unit only spit out water from the snout and the 2 sidebyside holes on the upper part of the midleg. Is this normal for this lower unit or is the pickup tube not sealing in the new water pump. I took it out for a spin and water did come out of the 2 holes but not as much as my old unit it would spit water and some exhaust about 3 foot behind the boat at idle and about 8 feet at full throttle. The motor didn't overheat or behave badly it was smooth shifting and didn't stall anymore. But I'm still worried about that water coming from a spot my old unit did not. Any advice or comments are welcomed and appreciated.

 

[Frank Acampora]

Re: leaking lower unit?

What? No one answered you?

The two holes you are writing about are in a position I have never seen. Usually they are underneath the cavitation plate. They drain two blind cavities on either side of the water pump.

Since you state that the collar did not fit your water tube, you have a smoking gun. Very likely the pump is blowing a portion of the output into the lower unit and this water is leaking out the weep holes. If the engine will not overheat during normal use, then don't worry about it. The Mercury water pump on your dual exhaust unit delivers more water than the earlier Force pump it replaces so you can afford to waste a little.

Also, be aware that my '93 dual exhaust has an impact hole for a speedometer. This hole is located about two inches above the gearcase torpedo at the leading edge of the lower unit. If yours also has it and if you do not use it or plug it. it will deliver a significant amount of water into the lower unit at speed. No harm though; it just blows out with the exhaust and the cooling water.

 

[grsmnky1]

Re: leaking lower unit?

yes these are on the cavitation plate, sorry the name escaped me when i posted the question. Thank you for the reply. i took it back apart and notice it has 2 places on the water pump to remove excess water or relieve pressure don't know which, but they dump into the blind holes you talked of. i hooked the ears up while i had it off to note the flow of water to the unit, water appears to bleed out of these machined holes quite naturally looking and dump into the blind area you spoke of. Having had the boat wide open, well, close to it, for about 3 hours of pleasure cruising, with no overheating i believe you are right about not worrying about it. also I noticed a 4 mph difference to the good, maybe a different gear ratio? Im just happy to be fishing again. thank you again for the reply

 

[Frank Acampora]

Re: leaking lower unit?

I have often maintained that the lower gear ratio is better for speed--like 4 or 5 MPH better.

I have almost all my engines running the 2 to 1 ratio lower unit gears.

Your original ratio was something like 1.78 to 1 and the dual exhaust is probably something like 1.95 to 1. Thus you gained not only top speed but most likely acceleration as well. If you have a tach take note of the maximum RPM it will most likely be 400 or so RPM faster than before