old mercury thunderbolt MERC 300 motor?

[drsawdon]

[colour=red] I just bought an old Mercury Thunderbolt "MERC 300" motor. It is white with a chrome shield around motor. I think it's from the 60's and i think it's around 35 to 40 hp. it has 3 pistons. I could not find ant kind of information on it anywhere. I tried to contact Mercury but they ask for 8 digit serial number. this motor only has 7 digits. does anyone know anything about this motor?
Mike: fb901@ncf.ca

 

[Chinewalker]

Re: old mercury thunderbolt MERC 300 motor?

Hi Mike,
The Merc 300 was a 1960 only model. 4-cylinders, 40-cubic inches, 35 hp. One of the greatest basic motor designs of all time, one that Mercury carried through up into the 1990s.
Much more information, parts, manuals, etc. available at Grubb's Marine (www.oldmercs.com)
Have fun with it!
- Scott

 

[Scaaty]

Re: old mercury thunderbolt MERC 300 motor?

Well, if it has 3 pistons, it probably won't run to well! As Chine says..its a 4 cylinder, and a super classic motor

 

[steelespike]

Re: old mercury thunderbolt MERC 300 motor?

Another good site for info and links Johns Old Mercury Web Site.

 

[drsawdon]

...

...

... It is a 4 cyl.

 

[Texasmark]

Re: old mercury thunderbolt MERC 300 motor?

Well pilgrim (as John Wayne would say) tain't a '60 Merc. Somebody modified something. But they where white back then. I had a 35 hp Merc from that era (mark 35 as I recall), and it was definitely 4 cyl with the wrap around chrome shroud (cowl) that Merc had for 10's of years.

Mark

 

[Scaaty]

Re: old mercury thunderbolt MERC 300 motor?

http://www.oldmercs.com/siteguide.html

Has pix..see what you own

 

[Chinewalker]

Re: old mercury thunderbolt MERC 300 motor?

drsawdon,
Look again. Top cylinder is up under the cowling. There are four cylinders, two carburetors. Each carburetor feeds two cylinders independent of the others. Mercury made a small 3-cylinder prototype in the 1940s (of about 9hp) and didn't produce another 3-cylinder until 1973 as the 65hp model 650.
- Scott

 

[Kodiak79]

Re: old mercury thunderbolt MERC 300 motor?

I have a merc 300 as well. Could anyone tell me how I can tell if the water pump is working.
Thanks for your time,
Jeremy