Originally Posted by mmwjr
What is the idle rpm set to? Do you let it idle for a few minutes before shutting it off?
Don't remember the exact idle speed off the top of my head. I did not let it idle when shutting off because we had swimmers in the water and I wanted it off to let them get into the boat. I know it's overkill but as a former ocean lifeguard, I would rather be safe than sorry when it comes to boating safety.
Also, the tank was full of an unknown fuel type, probably 87 when I got the boat. I'm in California so 91 is the highest octane we get. All but one of my vehicles require 91 so that's what we get. The odd one typically gets 89 but will get 91 if that's what is available. The next trip out with the boat, we'll put in 91.
The recommendation for higher octane on the boat makes perfect sense to because engines tend to run hotter and develop less power with less octane. We don't realize it in our cars because modern computer controlled cars will automatically retard the timing if it senses a knock or ping due to lower octane. The boat doesn't have that ability.