Marvel Mystery Oil

[Little Red Tractor]

I now use a different product in my modern "stuff" but would buy another bottle of MMO if I have any older engines.

My dad had a shop in which he repair farm equipment--and anything else that go dragged in--from the 1950s to his retirement in the 80s. Always a barrel of it open and one on hand for the open one ran empty. It went into the fuel on everything and into the crankcase on almost everything.

The salesman would say, "It's a marvel what it does, and mystery how it does it." ...but he sold a LOT of the stuff.

 

[JRH02]

Like many others I have used it for 50 years for multiple things. With machine tools as a cutting fluid with problem materials like stainless for drilling, cutting and tapping. Yes, I run some periodically (every other tank or jug) in the chain saws, and generator, gas or diesel ATV/UTV. In my opinion it is just OK for penetrant on stuck/rusted hardware but I think there are better options these days. Gun lube is a yes - as sparingly as possible.

I never put it in any crank case as I run Mobile1 in everything and that is good enough.

Lastly, it smells so good.

 

[ROUSTABOUT]

I used it to winterize an inboard boat engine.

My grandaddy was born in 1900. He always had it and so doeth I.

 

[benski]

Pretty um, Marvelous stuff. I don't add it to the Amsoil motor oil I use, but it goes into a lot of things around here as a fuel additive, stabilizer, outdoor tool treatment, air tool oil, and the occasional stew recipe. (Um, no...) but it is great stuff, especially for loosening up stuck/frozen stuff and off season protection. I'm a 50 year user, and there are things that it excels at.

 

[ncridgerunner1]

Haven't used it in years but back in 1986 I bought a 1969 Chevy pick-up with a 305 engine that had a bad valve tapping noise. Bought the truck for nearly nothing with the belief that I would have to do a valve job at the very least. A mechanic friend convinced me to pour MMO directly into the carb while the truck was running. It smoked like someone had set off a couple of military smoke grenades but ran quiet and smooth afterward. Wish I had that truck today.

How much MMO are people using to stabilize 5 gallons of gas?

 

[DJ54]

I wouldn’t think adding MMO to engine oil would be very good for any engine oil. Add it to fuel yes but I want my engine oil thick especially in old engines

Instructions say up to 20%, but I add maybe 10%, only one oz. per qt. And use SAE 30 in all of my air cooled engines, so it can't thin it that much, even when hot. Been doing that since the mid-70's hasn't seemed to harm anything yet.

 

[DJ54]

You could mix up a small batch of mmo and acetone for penetrating oil. you may have to add more acetone if it sits a long time

If he doesn't have a use for it, that would be a great way to use it up. I've got a gallon Dad bought back in the 80's. I called MMO's help line to check how long it was shelf stable, and they told me if over 10 years old, don't use it in an engine, but didn't say why. That's exactly what I'm going to do with it, once I get the 2 gallon jug of ATF used up, then starting on a case of Rislone I found he'd squirreled away.

 

[olenjohn]

Air tools

 

[olenjohn]

I could post it here but then it would no longer be a MYSTERY….

 

[joea99]

I've been using a 50/50 mix of ATF and Acetone as a penetrating oil which I am now a believer in/of. My nephew asked if MM would work as well.

Maybe give that a try and compare to Kroil, PB Blaster, etc.