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View Full Version : Raw Water Pump Gasket for '74 MC


pasmadj
08-31-2009, 01:09 PM
I ordered a RW pump gasket from an MC dealer - over the phone. The one they sent me is a 4-bolt style (see photo). The gasket diameter is too small.

I attached pics of my pump.

I checked the Skidim website, but I don't see anything that looks right.

Any suggestions?

Also, does it look like the impeller West Marine sold me is the wrong diameter? Shouldn't ALL of the vanes be bent a little to allow for wear?

Kummer
08-31-2009, 02:14 PM
Just use Permatex Sensor-Safe Blue RTV Silicone Gasket Maker (http://www.permatex.com/products/Automotive/automotive_gasketing/gasket_makers/Permatex_Sensor-Safe_Blue_RTV_Silicone_Gasket_Maker.htm)it is better than a gasket if you ask me,,,

pasmadj
08-31-2009, 02:20 PM
Just use Permatex Sensor-Safe Blue RTV Silicone Gasket Maker (http://www.permatex.com/products/Automotive/automotive_gasketing/gasket_makers/Permatex_Sensor-Safe_Blue_RTV_Silicone_Gasket_Maker.htm)it is better than a gasket if you ask me,,,

I've used that before in different applications. I did think about using it again. I tried the Permatex Form-a-Gasket II - only because I had it in my toolbox. But, it may not up enough.

The proper gasket would prevent the need to scrape each time I replace the impeller. But, an adequate substitute no doubt.

Thanks for the suggestion.

thatsmrmastercraft
08-31-2009, 02:21 PM
If you go to a real auto parts store you can buy gasket material and cut your own gasket. That would hold up better than the permatex in this application.

bigmac
08-31-2009, 05:40 PM
685008 is the Indmar part number for the gasket for the Johnson F6B-9 pump they currently use (685007 is their part number for the impeller). That doesn't help you much because you have a Sherwood raw water pump. Most of the Sherwood pumps these days use an O-ring to seal the cover rather than a gasket, so you might have to make your own. The bigger problem is going to be finding impellers, maybe. Below is the standard matrix of model numbers for the impellers if you can't get help from SkiDim.

As to size of your current impeller and how the vanes fit...here's a picture of the correct impeller in a Johnson pump



.

pasmadj
09-01-2009, 12:22 PM
Thanks bigmac. I have been exchanging emails with a guy from Sherwood. I sent him this photo of the backside of my pump. It looks to me like the pump number is "F75". I also took some more measurements. The inner diameter is 2 1/2". The depth is 1 5/8". Based on all of this, I think I need the 10615K impeller. I will get one that includes gaskets. I will post an update.

bigmac
09-01-2009, 12:32 PM
Thanks bigmac. I have been exchanging emails with a guy from Sherwood. I sent him this photo of the backside of my pump. It looks to me like the pump number is "F75". I also took some more measurements. The inner diameter is 2 1/2". The depth is 1 5/8". Based on all of this, I think I need the 10615K impeller. I will get one that includes gaskets. I will post an update.

FYI, here (http://www.sherwoodpumpsdistribution.com/FileAttachments/Marine-Distribution/en-us/MPG_F75.pdf)are the design drawings of your pump.

The impeller kit is indeed the 10615K. It's about $30 and includes the gasket you need.

Frankly, I'd be looking at some way to replace that raw water pump. There is currently no rebuild kit, nor is there a direct replacement pump for the F75. If the bearings go out on this one, you may have a scramble on your hands.