1973 Mercury 7.5 Fuel/Oil Mix?

[johnwayne]

New to forum, first post. Just used the forum to find year of the motor but not sure about fuel/oil mix and if it depends on year of motor? Also is today's unleaded fuel ok? Sorry this is a basic question.

Duke

 

[JB]

Re: 1973 Mercury 7.5 Fuel/Oil Mix?

50:1 will work just fine, Duke.

 

[mbanko17]

Re: 1973 Mercury 7.5 Fuel/Oil Mix?

Yep 50-1 , Look for a gas station with out ethanol, trust me. This gas for 2 strokes is what you need for old motors. I have a 75 Merc and a 56 Johnny. This gas sucks. My 2002 Jeep even runs like **** when I uuse gas with ethanol.
TREE HUGGERS SUCK! Careful who you vote for?

 

[johnwayne]

Re: 1973 Mercury 7.5 Fuel/Oil Mix?

Thanks for the help with the oil mix and advice wrt to not using ethanol. 'Drill here, Drill Now'.

We bought the motor with an old 12ft aluminum starcraft on the way to a camp at http://lakesis.com about 5 hours from home. Didn't know much about motor but the old owner had the prop submerged in a bucket of water when we looked at the boat/motor, pulled the rope 1 time and it started right up. I don't remember if it was drawing water.... long story short, put it in the water for a test run with the wife/kids this afternoon and found it would not circulate water, and would not go into fw/rev. We also had a heck of a time registering, lost title, wrong name filled out on the transfer paperwork. We went 100 + miles to get the paperwork redone with the owner, then registered, happy, then found at back at camp the motor would run but not work. After checking the water cooling line for blockage the guys at the marina said they think 3 things are bad, impeller for cooling, prop not spinning because the 'hook' on the bottom of the motor was hanging out, and possibly the fw/rev linkage is broken. Live and learn. We spent 475 for boat/motor. Told the wife we could have lost that in 30 minutes at a casino (don't gamble) Marina guys thought I could probably fix with ~ 60 in parts. Tomorrow's a new day.

God Bless!

 

[8075mercury]

Re: 1973 Mercury 7.5 Fuel/Oil Mix?

Sorry to hear about the problems, these are great little motors.

I think I would check the compression with an auto type gauge, looking for 100psi+ in each and check the lower unit oil for water. Sounds like you already have spark.

Then get a factory manual off ebay or Seloc and replace the impeller. I do not know what the "the 'hook' on the bottom of the motor was hanging out" means? photo might help. The "fw/rev linkage might be broken" can mean a number of things.

If you have compression and the lower unit is good (if original though, this year did have carbon steel drive shafts which rust), there are many folks on this forum who can get you going. Need your serial number off the transom bracket too.

Good luck.