PICS: Does this impeller housing need a seal 50hp 4 stroke

[Zerex]

I'm still fighting with an intermittent over heat as described here http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=29;gtid=1098595
But now i've changed the impeller, thermostat and backflushed the engine still with no solution to my problem.
So I noticed when I cleaned my impeller housing before reassembly there was a little soft worn out something????(O-ring,Seal) around the pictured area around where the driveshaft slides through. I thought it was crud so I cleaned it out but now I'm second guessing thinking maybe this housing needs to be sealed around the driveshaft?
Here's the pics of the area

Anybody know?
1998 Mariner 50hp 4 stroke

 

[Zerex]

Re: PICS: Does this impeller housing need a seal 50hp 4 stroke

Anyone done a similiar impeller before?

 

[rickdb1boat]

Re: PICS: Does this impeller housing need a seal 50hp 4 stroke

Do you have the serial number handy?

 

[rickdb1boat]

Re: PICS: Does this impeller housing need a seal 50hp 4 stroke

It looks from the diagram that there is a washer that sits between the impeller and housing...#15 in the pic....

 

[gss036]

Re: PICS: Does this impeller housing need a seal 50hp 4 stroke

That is probably the item shown in the bottom picture. It look like it has a seal in it. # 14 looks to be the water tube which would allow the water to move to the engine block for cooling.

 

[Zerex]

Re: PICS: Does this impeller housing need a seal 50hp 4 stroke

Both 15 and 17 are nylon bushings which I have in place. I went to the Merc dealer and I'm not missing anything. He said that ti sounds like I've got a faulty temp sensor.
Thanx Guys

 

[Zerex]

Re: PICS: Does this impeller housing need a seal 50hp 4 stroke

Well I hooked up a pressure gauge to the motor last night and it seems like my readings are too low. 0-2 psi fluctuating at 1000rpm and 5-8 psi fluctuating at 4000rpm. So I'm thinkinking now that I have salt deposits buit up somewhere in the motor.
Does this sound logical?

 

[ricksrster]

Re: PICS: Does this impeller housing need a seal 50hp 4 stroke

I have a Teleflex guage and hooked it up per instructions. The readings are identical to yours. The Mercury manual I have says you should have a minimum of 5 PSI at WOT through any turn or manuvure ( I can't get the spell checker to work ).

 

[ozziebob]

Re: PICS: Does this impeller housing need a seal 50hp 4 stroke

No seal is required. How did the impeller look when you pulled it out? If it looked bad it may be a case of the adapter may not be seated properly when you reinstalled the lower unit. Part # 14 can sometime not line up with the pump and p/up tube.This will be vissable because the rubber inside will have a mark in it. What in effect happens is the water flow is cut and the engine overheats at low rpm sometime only at idle. Because pressure increase at higher rpm. engine usually cools o.k.when you get going . .... Just a sugustion. I have been caught before

 

[Zerex]

Re: PICS: Does this impeller housing need a seal 50hp 4 stroke

No seal is required. How did the impeller look when you pulled it out? If it looked bad it may be a case of the adapter may not be seated properly when you reinstalled the lower unit. Part # 14 can sometime not line up with the pump and p/up tube.This will be vissable because the rubber inside will have a mark in it. What in effect happens is the water flow is cut and the engine overheats at low rpm sometime only at idle. Because pressure increase at higher rpm. engine usually cools o.k.when you get going . .... Just a sugustion. I have been caught before

Original impeller looked fine, but I installed a new 1 anyways. Lots of water out of the spitter and the plug at the top of the motor where i hooked the pressure gauge. I verifed the temp sensor sets off the alarm at 175 degrees. I wouldn't think that I have a blocked passage because that should cause a higher then normal pressure reading on my gauge. I'm totally stumped. The water tube #14 seems tight on the impeller housing and copper pickup tube. Maybe it's come loose where it attaches to the powerhead and it's bleeding pressure from there?
Should i test the motor without a thermostat to see if it overheats still?
Thanx
Jason