mercury 500

Joined
Jan 14, 2008
Messages
9
Im just curious about how good and reliable a 1971 mercury 500 and about how powerful the water comes out of the water port
 

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: mercury 500

The 4 cyl. 50s were one of the most reliable ever built. The telltale should have a steady stream of water but they do plug up from silt and have to be cleaned once in a while
 

tmcalavy

Rear Admiral
Joined
Aug 29, 2001
Messages
4,005
Re: mercury 500

Had a 73 Merc 500 and never got a real powerful stream out of the telltale when the engine was idling between 800 and 1000 rpm. So that was kinda deceptive, as it would put out a good stream at higher rpms...on the muffs and out on the lake. If you can touch the waterjackets and hold your hand on there when it's running, the water pump/cooling system is doing its job and everything is ok. If it's too hot to touch, time for some pump/system maintenance. Those are great outboards, very strong and reliable.
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: mercury 500

I agree - great motors. However, there were some weaknesses. Keep an eye on all wiring under the cowling. Older Merc wiring had a problem with the sheathing cracking and crumbling. Also, the early 1970s models still had steel shafts that were prone to rusting, particularly under the waterpump cup where the upper main seal is. If you're getting water in your lower unit oil, there's a good chance that's where it is coming from.

Unless the guy you're buying the motor from can produce an invoice showing that the waterpump was changed within the last year, replace it. Cheap insurance...
- Scott
 
Top