Water inlet line pulling a vacuum

[Muqwump]

Re: Water inlet line pulling a vacuum

STill havin problems..... I took the out drive back off and took the pump apart again. It looked brand new still. I did find out some things that someone might know... In the OEM Service Manual it calls for a Oil seal (#31)at the top of the water pump body Assy with a rubber ring as well. The kits do not come with this seal? Was this seal discontinued or do i have to order it seperate? I put the muffs on and water just pours out the top of the housing. This may be normal but just need clarification. Thanks This is a I/L 6 165 1 DRIVE without the vent ports (1970-71).

 

[Muqwump]

Re: Water inlet line pulling a vacuum

*Clarification* " The leak is Around the shaft at the housing", Not where the water tube goes... I had caped that line to perform that test on the housing at 28 PSI Of H2O.

 

[Muqwump]

Re: Water inlet line pulling a vacuum

*Clarification* " The leak is Around the shaft at the housing", Not where the water tube goes... I had caped that line to perform that test on the housing at 28 PSI Of H2O.

This was capped with a gauge and 28 PSI = City water pressure. The gauge is working properly and never moved 1 lb.

 

[BAYLINER185]

Re: Water inlet line pulling a vacuum

water pours out the top of the houseing ok....Do you have the little copper / brass pipe connected at the to pof the water pump housing. It connects to the top of the housing and goes up in the upper unit. You may be missing a part.

Ok but then again you say your getting water at the shifter lever. This is on the inside of the transom so I can only assume there is a leak at the water tube or quite posibly the water hose is not installed all the way on the tube. Thats where it sounds liek it leaking to me.

 

[Muqwump]

Re: Water inlet line pulling a vacuum

Thanks for the help... I have the outdrive off with muffs on. I took the brass pipe on inserted it into the top of the housing with a piese of hose and a gauge hooked up yo it. Then i crack open the water and with no resistance, the water flows out the top of the housing. The might explain why i am not getting water to the engine.?? it is all dupming out around the shaft before it can go up the water tube. Is there another test i can do before putting the outdrive back on again? Thanks

 

[CharlieB]

Re: Water inlet line pulling a vacuum

Do I understand that it is when the drive is installed and the city water is on that the water is coming oout at the shift linkage BETWEEN the two gearcases?

The water pump should have a gasket that looks sort of like a 3/16 inch section of a black rubber hose. This is really a seal as you would normally think of a seal actually sealing and stopping flow, it is more of a flow restrictor. By design the water pump leaks an amount of water which flows back down over the pump housing to provide additional coolling from exhaust heat.

Double check the pump outlet and the short transfer tube up inside the bottom of the upper gearcase. A mismatch or poor seal between these two and no cooling water can get to the engine.

 

[ziggy]

Re: Water inlet line pulling a vacuum

the seal at the top of the waterpump can be used, or not used, the way i understand it.

did ya put the centrifical slinger (rubber ring) on top of the waterpump body?

did ya put the impeller drive pin back in between the impeller and the drive shaft assy. ?

I took the brass pipe on inserted it into the top of the housing with a piese of hose and a gauge hooked up yo it. Then i crack open the water and with no resistance, the water flows out the top of the housing. The might explain why i am not getting water to the engine.??

i'm not conviced that's it.... since yer feeding it water when it's staic on the bench. i'd think that would be a logical place for the water to flow out since there aint a seal there. however when the impeller is spinning. it works like dons is talking about.

The pump work by the impeller vanes straightening out while over the intake port of the pump housing, then you have water between the vanes and the exit for the water is blocked from the intake, and starts opening on the oulet port of the pump. The vanes then start squeezing down and push the water out the only place available. The outlet side of the pump.

 

[Muqwump]

Re: Water inlet line pulling a vacuum

Do I understand that it is when the drive is installed and the city water is on that the water is coming oout at the shift linkage BETWEEN the two gearcases? Yes, then i droped the outdrive again to see where the water was coming from.

The water pump should have a gasket that looks sort of like a 3/16 inch section of a black rubber hose. This is really a seal as you would normally think of a seal actually sealing and stopping flow, it is more of a flow restrictor. Is this the centrifusual ring that is located on top of the housing on the shaft? Like Ziggy is talking about?
Double check the pump outlet and the short transfer tube up inside the bottom of the upper gearcase. A mismatch or poor seal between these two and no cooling water can get to the engine. The cooper tube through the transum was hydro tested at 20 PSI and held for 12 min with a drop of 1 psi.

Once bled it down, I hooked up a hose to the water tube and had full flow to the thermostat housing.

 

[Muqwump]

Re: Water inlet line pulling a vacuum

Update... I have had three service centers for mercruiser work on this boat. I got tired of paying for the same thing every time i went in and the boat never was fixed. Yes, they stood behind there craftsmanship for what they had done as far as what they thought was wrong, but never fixed the problem. So i started working on it myself, my grandfather just wanted to take it for one more spin around the bay and i am determined to do just that.

I just changed vendors for ordering parts last weekend because the other vender was really getting to like all the money i was spending replacing the same parts over and over. In doing so, this new company also offers service as well. The guy there was throwing me the sell pitch for service, which i heard over and over for three years now, and i didnt really want to hear it. He ordered me some more parts that he didnt have in stock and i picked them up yesterday. Before i left, "2 hrs later", he gave me some great advise and we walked through everything that i have had done to it in the past three years. You know what he said.... Why dont you try filling up the water pump through the thermostat and lines up through the manifold to prime it. I told him i have never tryed that and noone has ever told me that either. I asked him what i owed for this and he said, "Nothing, but if it works I like Crown".

I took him a case this morning...

 

[Don S]

Re: Water inlet line pulling a vacuum

Glad you got it working, but let me say this. I change a lot of those pumps EVERY year. And I have never had to prime one. Just put it together, put the muffs on, turn the water on, start it up and it works.

 

[Muqwump]

Re: Water inlet line pulling a vacuum

I am still stumped on how it was pulling a vacuum at the thermostat where the inlet came in at.??? I was looking it over again today to try and figure it out and found another possibility maybe?? When he said to prime it, all i was doing was displacing the air with water. So there is water that stays inside of the exaughst manifold and lines up to the riser. Right? So i was wondering why i wouldnt still have water inside the system since it was replaced with air. Then i found there is a leak at the exaughst manifold to the head when i was running it. I am going to try and re torque it to see if that stops the leak. It also looks like it is in the same area the head was repaired at when they rebuilt it. And it hasnt run since then. Again, I appreciate all the help that i have recieved on this matter.