Mercury Thunderbolt 500 - 1980?

Joined
Sep 8, 2013
Messages
17
Serial: 5684413

First off, thank you in advance for the help. I'm pretty new to the marine world but 15 years deep in automotive.

I've recently come across this 50 hp Merc and it needs some help. I know I'm missing a few parts; flywheel being the main one. I know absolutely nothing about this engine and can't seem to figure out exactly what I've got in order to get the parts that I need to see if this thing is still workable or not. As a general rule, is this a pretty good engine? Do you suppose it's worth my time and money to see this through? I know they're ambiguous questions and don't expect concrete answers.
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In addition to the engine parts I need, I also need the external wiring harness and the controls for the engine. Does anybody know where I might be able to pick this stuff up... on a budget?

Again, thank you for your time - it is much appreciated!

Dustin
 

bilge rat jim

Petty Officer 1st Class
Joined
Jun 28, 2012
Messages
330
Yep, that's an 80-81 4 cyl hp. If it's electric start, the the flywheel is still available through Merc, for a mere $600. :lol: Controls from any Merc outboard from about 1975-1995 will work. You'd be wise to look around for a donor motor for your parts.
 

Mi duckdown

Commander
Joined
Apr 14, 2007
Messages
2,575
The bad part of not having a flywheel is you can't check compression to see if is even worth spending Any money on it. I guess if you had the correct Nut for crank you could spin it to check Compression.??? I'm SURE there are people out smarter than Me, that will chime in.
 
Last edited:
Joined
Sep 8, 2013
Messages
17
Thank you for the responses.

I found a use flywheel, so I'm going to pick that up and see what kind of compression I've got and then go from there.

Thanks again!
 
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