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Marvel Mystery Oil.

It was in 1982 I purchased an Airtractor powered by a Pratt and Whitney R1340 engine. My previous aeroplane was a Piper with a 6 cylinder Lycoming engine which burnt 65 litres of fuel per hour, or approximate. Now this big new aeroplane with a big fuel gulping engine burned double and I found this a little frightening so I ferried and worked at low power settings. Well oil consumption didn’t settle and I worried about that too.
Well the Australian Airtractor dealer sent a principle from the engine overhauler speak to me. The overhaullers were Aeroengines of L.A. and Vern Truman was the rep and he was also a part owner of the business. Mr Truman was also a gentleman of the highest class. He quickly determined the cylinders had glazed and recommended Marvel Mystery Oil. I just couldn’t understand what Mr Truman was saying because of his broad speech accent. Marrrvimisttrryall. At my request he wrote the name of the product and I understood. Now his instructions on how to use MMO was simple and made sense to me.

At the end of the day remove the aluminium tube to the manifold pressure gauge, idle the engine at 700 rpm and through the disconnected line suck up a quart (I think) of MMO. Turn engine off with the key and not the fuel shut off which is normal practice. 700 rpm so as the supercharger would blow it to all cylinders and the slowly running engine would not burn all the oil. The next morning do a normal takeoff and the carbon and other unwanted deposits would blow out the exhaust. Yes it did work. Another old time operator said he was recommissioning an old engine and he filled each cylinder with MMO , one at atime, replace the spark plug and pulled the engine through by hand thus ensuring the MMO was pushed through the piston rings. Leave for a few days, crank and run then do an oil change.
I had not considered using MMO in my A Models but will start now. I have a sticky valve which MMO has a good chance of freeing up.