If you have ever spent any time in an auto parts store you have seen the bewildering array of additives, cleaners, and other potions for fuel, oil, transmission, power steering, coolant, hydraulic brakes, etc.
Maybe some of them even work — who knows? I sure don’t, and generally steer clear of magic solutions of every kind … it’s in my DNA, I can’t help it.
But for some reason one day last year I spent like 20 minutes looking at these products, figured “why not?”, and bought some Marvel Mystery Oil and added it to my fuel for a few weeks.
It’s supposed to clean your fuel system, heads, valves, etc, along with increasing MPG. It seemed to help with mileage, but I didn’t check it that carefully, so I could very easily be mistaken on that.
This guy tries it on his lawnmower, along with a well-known competing product, Seafoam. He even hooks up a compression tester — but this is a little over my head since I don’t know how to interpret the results. Too little is bad, but so is too much, I think.
Seafoam vs Marvel Mystery Oil
Compression testing a lawnmower with some interpretation of the results — the numbers are specific to the motor, which makes sense. These numbers are published by the manufacturer.
An overview of compression testing and what it diagnoses — but for a car, not a lawnmower.