Mercury 90hp Tower of Power ID and advice

[sveevers]

Hi all,

I'm new to boating and outboards and I have acquired a boat with and old Mercury Blue band 90hp and was just looking for help ID'ing the motor and general advice.

The serial number is 6026943, is it possible to get year and other details from this?

The motor seems to start and run okay even after it's been sitting for a while. I'm not sure if this motor originally had oil injection or not but if it did it has been removed and I am mixing fuel at 50:1. I know it is best practice to replace the impeller as I don't know when it was done last but I would like some advice as to how the water pump and telltale should function. At the moment, there is no water coming out of the telltale until the revs are up pretty high, I assume it should be coming out even at low revs. Also, should I see water coming out of the middle of the prop or is that solely for exhaust gases. The other thing I notice is that the leg gets hot to touch is this normal or a sign that the water is not pumping?

Thanks in advance for any info.
Steve

 

[roscoe]

Welcome to iboats.

You have a 1982 model.

No oil injection in '82.

Water should come out the telltale at all rpm.
But it does take 30-50 seconds before it comes out on both of my inline 6 motors.

FYI, there is no thermostat on that motor.

Yes, exhaust and cooling water are mixed coming through the leg, and both exit through the prop hub.

 

[sveevers]

Thanks.
Is there any way to find out the part number for the impeller and seals etc?

 

[Chris1956]

Impeller repair kits are avail at the dealer and at many places on the web. It is likely that Sierra and Mallory make repair kits as well. You need to see what parts you need. As a minimum you will want new gaskets, Orings, wearplate and impeller. You may need a new upper housing and perhaps a new pump base.
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If the SS liner in the pump cover is scratched or worn, replace it. If the driveshaft seal in the pump base is work or leaks, replace the pump base.