Mercury 500 questions

Jagerace

Cadet
Joined
Sep 3, 2007
Messages
17
Hey guys. Got a heck of a deal on an older merc with a bad lower unit. I had a LU in the garage that would bolt right up. I put them together today and she fired right up but didn't pump any water. Serial number is 3576176. I would appreciate it if someone could link me to a waterpump rebuild kit. The the housing is just fine.

Ive read I need to connect a water hose to the copper waterpump tube and see if it comes out the pee hose?

From searching the forum I also see that my motor has the pee hose routed around the motor and I need to cap that and find another place to tap into. I cannot see where that needs to happen due to its very low location.

Any advise would be great. Josh
 

carholme

Rear Admiral
Joined
Sep 4, 2010
Messages
4,845
Re: Mercury 500 questions

That s/n comes up as:

50 500 4-cyl 3478003 3816307 1973 USA

From here:

Mercury 2-takt, 4-cyl, 40 - 85 hp, produktions?r, modellguide

If you look at item 11 under CYLINDER BLOCK AND CRANKCASE ASSEMBLY in the parts list, that is the original fitting where the telltale hose attaches to. You will see it looking from the rear of the engine just to the lower left of the #4 (lowest) sparkplug. If you want an alternative tap for water pressure you can use plug, item 4, at the top of the block in the same link.



Gerry




MERC 500 - Mercury, Mercruiser, Force, etc. Parts Lookup

See water pump parts under GEAR HOUSING ASSEMBLY, COMPLETE (PAGE 1). I think you will have to order the individual parts you need.
 

carholme

Rear Admiral
Joined
Sep 4, 2010
Messages
4,845
Re: Mercury 500 questions

That s/n comes up as:

50 500 4-cyl 3478003 3816307 1973 USA

From here:

Mercury 2-takt, 4-cyl, 40 - 85 hp, produktions?r, modellguide

Parts list:

MERC 500 - Mercury, Mercruiser, Force, etc. Parts Lookup

See water pump parts under GEAR HOUSING ASSEMBLY, COMPLETE (PAGE 1). I think you will have to order the individual parts you need.

If you look at item 11 under CYLINDER BLOCK AND CRANKCASE ASSEMBLY in the parts list, that is the original fitting where the telltale hose attaches to. You will see it looking from the rear of the engine just to the lower left of the #4 (lowest) sparkplug. If you want an alternative tap for water pressure you can use plug, item 4, at the top of the block in the same link.



Gerry
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Re: Mercury 500 questions

I did the top plug, item #4 on mine because I had no plug #11 and I wanted a tell-tale. I like that the pee hole from the top of the block reduces the chance of an air pocket in the upper water jacket. Probably just an invented potential problem in my mind, but I feel better.
 

Jagerace

Cadet
Joined
Sep 3, 2007
Messages
17
Re: Mercury 500 questions

I cant find the plug after doing some looking. Do I have to remove something first?
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Re: Mercury 500 questions

On mine standing at the rear, the plug is between the flywheel and bracket #18 on the Top Cowl Assembly parts diagram, more towards the left. I could see the plug without any removal, but the bracket had to come out to remove the plug and put in a barbed elbow
 
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