I have a 1965 Johnson 40 horse that i drained the lower unit oil out of and now i want to know what i should use for lower unit oil. Is there a commercial oil for the motor? Or should i just use a 80 90 gear lube?

I dont know the wieght of oil to use,but I've always picked up lower unit oil at the boat shop or Wallyworld

Use lower unit oil.

Check with a local boat service department and ask them what they suggest you use.

Do not take any chances with the lower unit oil.

SAE 80W-90, Thats usually the standard but you might need to do some research with your older motor.

I have a 66 40hp johnson. The electromatic needs type C oil. It's a bit thinner.  

I just found this on some forums this winter but I previously ran the standard lower unit oil in the motor for 3 years and hadn't had any problems. I'm definitely switching to the type C this spring though.

I always use the oil from the motor maker. There are probably others a little cheaper but you rarely change more than once a year so why push your luck!