why no seal between water pipe and water pump?

[shindig888]

Just replacing the waterpump on my 91' force 50 and have been worried by the fact that there is no positive seal b'tween the pipe and plastic bit on the pump. Me being crafty, machined an o-ring groove in the "plastic bit" . But now am worried that maybe I might blow a gasket somewhere because I did this... Mercruiser must have thought of this seal. Why is there not one, And is it good I put one in? The pipe has clearance at this fitting. Will I get enough water to the head without a good seal?

 

[shindig888]

Re: why no seal between water pipe and water pump?

any help would be welcome as I would like to get her together. Roscoe?

 

[panther150]

Re: why no seal between water pipe and water pump?

I wondered this myself. All I can tell you is that mine works without the seal. jm

 

[shindig888]

Re: why no seal between water pipe and water pump?

Roscoe.! Where are you man? You always have an answer to my problems... Does anyone think a ducks butt is necessary here? Im mean, why would I replace my W.P. if the pipe fitting leaks like a sive? These Farce seem to piddle whatever cooling water they've got. Can this be improved?Is there a bypass if the thermostat is closed? Will the pump be running at max pressure if it is? Shoot.. why? If the thing leaks so bad, is that the reason to replace the pump every year or two? just to make up for inefficiency? Anyone...Opinions..:/

 

[WillyBWright]

Re: why no seal between water pipe and water pump?

Annual water pump rebuilds are advised by all motor manufacturers from what I've seen. It's the single most important and most easily damaged component for a motor. Without it, the motor dies a horrible and painful death. It has to be healthy ... always. If it fails, the motor dies. If you wait for it to fail before you service it, you boat with great peril. Realistically every 3 years is not unreasonable. 5 plus and you're begging for disaster.

There should be a plastic funel-like fitting between the pump housing and the pipe. As I recall, the pipe fits rather snugly into it. The thermostat is spring loaded allowing the thermostat to act as the bypass when water pressure is strong enough to unseat it.

 

[Realgun]

Re: why no seal between water pipe and water pump?

Basically there is no seal cause the water is not going to get out of the lower unit as it is underwater during operation. The drive shaft has a seal however.

Or it could be that at 800 rpms ther is enough flow to handle the motor. At WOT there is an excess and the water needs to go somewhere other than the passages.