Using Marine PRO to clean a 1977 Johnson 9.9 outboard [SOLVED]

I have 1977 Johnson 9.9 outboard that I just purchased. I put clean clear gas in the tank and added 2 stroke oil at a 50:1 ratio. What would be the best amount to add per gallon to clean up my engine?

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Jim D.
2 years ago

That’s a great question, John. You cannot add too much Sea Foam or Marine PRO to fuel. The more you add to fuel (higher concentration), the better and faster it will clean your outboard’s carburetor and chamber areas. If you’re hoping to do a thorough carburetor cleaning, go ahead and add a whole can of Marine PRO to the fuel tank and operate the engine as normal. For what it’s worth, I always like to add Sea Foam or Marine PRO when a fuel tank is low for an extra cleaning punch! Can always add more fuel later.