7.5 mercury 1970 model questions

[CAPnCLETIS]

does anyone know what fuel mixture to run this engine on? also, i was wondering what anyone would recommend doing to this motor before running, it was winterized 8 years ago and hasn't been ran since, just sat in the barn. i changed the lower unit oil, but i was wondering if i should spray anything in the carb before fueling it and trying to start it
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[Starppy]

Re: 7.5 mercury 1970 model questions

You definately want to change the impeller....On second thought, get a complete pump kit either Merc or Sierra will do fine.

Spark plugs would be a plus too. If there is rust on the plugs, be sure to soak them with penetrating oil before you try to remove them. Sitting in a place with moisture can cause corrosion and if you torque too hard to get them out you may strip the threads on the head. It is aluminum do not forget.

A tune up may be in order too. The points could be corroded and the condensers may be bad. At least do the plugs and pump and see if she starts. If she starts hard or won't start at all, then you will have to do the points and condensers.

Other things to check before starting would be the condition of the fuel lines and the condition of the fuel pump. Look for leaks when you connect the fuel line and pump up the ball.

Water pump, fuel pump and tune-up kits are still pretty available for those. If you have a hard time finding stuff, check http://www.oldmercs.com

 

[Starppy]

Re: 7.5 mercury 1970 model questions

By the way, fuel mix should be 50:1 (roughly 2.6oz oil to 1 gallon of gas). Use a good, brand name 2 cycle oil with TCW-3.

I also recommend at least mid grade gasoline or better yet, premium 93 octane. Those engines were built before they were adding ethanol and seem to do better on modern premium that does NOT have ethanol. I have also noticed that the older Mercs started having problems with rotting fuel lines when ethanol blends came out. That's my opinion of course.