Re: What year is my electric start 40 H.P. Mercury outboard
Jim;
That's better as it looks like a Canadian built engine by the s/n. It comes up as a 1975:
40 1975 ML 4117710 7047608
From here:
http://www.maxrules.com/Merc_model_files/25-40CYL2.html
As the Canadian number begins 1975 at 7046806 and the 1976 year begins at 7070273 which is too high for 7048764, yours is a 1975.
Parts listing:
http://www.crowleymarine.com/mercury-outboard/470.cfm
It is a Merc 402
40:1 is ok but you can use 50:1 with modern oils. Sometimes 40:1 is better if you are not having any fouling problems as people tend to lean the carbs for what they think is best idle but it is usually too lean and the engine suffers over time from lack of lubrication.
If you look under this section:
GEAR HOUSING ASSEMBLY, COMPLETE (PAGE 1)
You will see the impeller and waterpump components.
Seeing as you just got the engine, this is a good time to do it.
Gerry