While we are on the topic of Amsoil.
My Boat runs a 79 power trim Merc 140 I6 cyl. (aka power tower) I bought it a few years ago, re freshed the cylinders, rechambered the heads and upped the compression to 160 psi, minor port clean up and polish, larger carbs and 3x 3" velocity stacks I would estimate the engine is pushing 170+ hp @ 5500. (over kill for my little 17' boat but hey... it's all good)
After it's rebuild I ran the engine in fairly aggressive 32:1 with Merc's Quicksilver oil fouled 4-5 plugs too mainly because I never let it wind out.
After an hour or so I switched tanks to my to 50:1 and ran the crap out of it.
After that tank of fuel I rejetted (drop down 2 sizes on the mains and minor mixture setting) and ran it on Amsoil Saber outboard 100:1
Instantly I could feel a big difference.
2 years in a row I ran it in the Canadian powerboat poker run, during this event that little engine runs WOT for 4-5 hours trying to keep up.
We were out for one last ride in the fall and the engine picked up a bad sputter, plugs all seemed fine, compression was perfect but while checking on the water, I damaged a spark plug hole (always use anti-seize on aluminum heads kids).
Anywho I removed the head to install a timecert and was kinda shocked to see ZERO carbon and 100% of cross hatching still remaining even on the bottom sides that have the most wear.
As it was I had a bad coil/coil post and voltage rectifier that were the cause of the sputter.
I’ve installed a Tiny tach/hour meter and I’m keeping teck of hours this engines been run and what speeds and all maintenance records to compare later on with other engines. But last I remember I was at nearly 200 hours of WOT running and another 200 or so at part or mixed throttle (tubing and skiing etc)
the boat is rated for 90hp so yeah.....its HUGE on there