TOPIC: Mercury 20hp Serial number

Hi, been a while, but I recently drug home another old boat. '63 Alumacraft 16' with a newer 20hp Merc. The only serial number I found so far is on the left side of the mounting bracket, #51834xx. I tried typing it into an online parts outlet, and came back 'Not Found'...Is there another # somewhere, or...??? Any help would be greatly appreciated...Thanks

That engine is a 1978, according to that serial number. Good engine.

...Thank You very much for the reply. That's about what I figured, the guy I got it from thought it was early 1990's... I have not tried to start it yet, but I've discovered that the L/U drain plug was missing, and it does not shift into reverse. I got a new plug, filled it, and tried pulling the cord while trying to engage the shifter but, won't go into rev. I did have the throttle on low... Do you know if there are any common shift issues, with these units? Or what to check first? Thanks

Update...I fired it up yesterday, and I did get it to shift into Reverse, while it was running.... It probably ran for a couple minutes, before water began coming out the port, after several minutes, water stopped coming out...I will get a new impeller....

I have a 1978. Your stripe package looks like a 1979. I think there were 3 years in a row that the motors were unchanged inside. Mine always struggled to shift into reverse when sitting and not running, but no problem when running. It did that from day one. I bought mine new as a last year leftover sitting next to the new 79's. Saved me about $80 back in high school, so that helped me buy other things. Great motor for me and still use mine today! Initial use was on my hand build wooden 8' Glen-L Marine Tiny Titan 3-point hydroplane. It ran 47mph with a double pitched, doubled cupped factory 2-blade (since the boat only weighed 87 pounds and motor was 94 pounds, it over-rev'd until I got the prop re-worked). I am 6'4" and was 185 pounds, so that was not bad for having a Gorilla in the boat. My brother could get 50mph out of it. It now chases fish on a 1956 Starcraft shallow sided 14'. Moves pretty well. Enjoy your motor!

Thanks for the reply, the '63 Alumacraft, that this motor came with is a 15" transom, and according to the tag will hold up to a 60hp, (I can't imagine that). But I have a couple 35hp BigTwin's with short shaft and tiller, one of those would probably be about perfect. I will probably put the 20hp Merc on my '79 'Gruman 4.4' 14'...

That factory transom looks really well braced...nice. Have fun with your project. Both seem like nice running combinations.