Marvel Mystery Oil?

[mestrezat]

I hope I'm not opening a can or worms BUT, does anyone know of a reason to add Marvel Mystery Oil to my diesel fuel for my boat engine? Some posts I've read swear by it increasing the performance of the engine and getting rid of the sludge that builds up. Other think it's a bunch of bunk. I've got a good bit of it on board(came with the boat) and so far haven't done anything with it but temped to after reading some of the post but thought I should throw it out here before I do it.
Any one have any practical experience with it--good or bad?

[sartorst]

http://www.jatonkam35s.com/DeuceTech...itive_test.pdf
It may clean injectors which is a benefit but may reduce lubricity according to this artical

[a64pilot]

I've used MMO for years, but in piston engine aircraft, it does have some detergent properties. I put in in the can't hurt, probably a waste of money, but if I had it for free, I'd use it.
Much more important to use a good Bio-cide in your fuel, MMO doesn't help there.

[autumnbreeze27]

I wouldn't buy any more, I believe a study showed it wasn't much different than adding engine oil so not worth the $$. I use seafoam...


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[stevec195]

Used this for years in aircraft radial engines and came to the conclusion that as an oil additive it did not provide anything a modern lubricant can do for you. The old guys used this in the 1930's because engine oil and ring design was crap. As an additive to fuel, there is nothing I could document that survived the combustion process which would impart anything beneficial on the valves or stems. HOWEVER, I did continue to use MMO all the while in the fuel as it did seem to increase the life of fuel bladders popular in aviation.


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[newhaul]

There was a study done by a lab that showed that memo is not actually any good to add to diesel fuel intact it actually reduced the lubricity of the fuel they tested 10 different additives. ( I will post the link when I find it again)

[newhaul]

Found it Lubricity Additive Study Results - Diesel Place : Chevrolet and GMC Diesel Truck Forums
Its on a truck forum but diesel is diesel

[sparrowhawk1]

Thanks newhaul great link.

[a64pilot]

Originally Posted by newhaul

Its on a truck forum but diesel is diesel

It is, sort of.
Those are common rail Diesels, specifically the Duramax. Anyway the early Duramax engines suffered injector problems. I paid $3,500 (parts cost) for a set of injectors and it took most of a weekend to replace them, they are buried inside of the head to reduce noise. Stock fuel pressure on this common rail is around 30,000 PSI I believe and when we Hot-Rodded them we pushed pressures to 50.000 PSI, and at those ridiculous pressures, lubrication becomes an issue.
But most of our boats aren't common rail, have far lower fuel pressure and fuel cleanliness is the big thing that wears parts on our fuel injection systems.

What interested me in that article is that the best lubricant by far I believe was Bio-Diesel, makes me feel a little better about burning Bio when I can get it.

[newhaul]

A64 you know what I mean BTW my diesel truck is a 1994 last year of id fords with 7.3