Ever hear of using hot to decarbon a running engine?

[hlw49]

My brother says he has ran hot water thru the engine while running to remove the carbon from an engine while running. Ever hear of it?

 

[andrewslarge]

I’ve heard of it. Some old timers call it “steam cleaning”. I’m 58 and haven’t heard of it in many years.

I’ve also heard of people swearing by Marvel Mystery Oil. MMO has lots of information online.

Yamaha has a fuel additive called “Ring Free”

My way to de carbon is to remove the head and clean it up. You’d be amazed at what oven cleaner can remove from the head! Just wear gloves and eye protection.

 

[sgkent]

room temp water. You warm up an engine and drizzle about a half cup of water in it while throttling it to avoid it stalling. Then change the oil. It will only knock the loose carbon off the cylinder head and piston, the firmly bonded carbon would require a constant drip of water to clean more of it.

 

[Auto Doc's]

Water= H2O which is 1 part hydrogen and 2 parts oxygen. It blasts carbon off the piston tops and upper rings when used sparingly. Basically, it is glorified steam cleaning the top end of and engine in-cylinder.

I grew up learning how to de-carbon engine top ends back in the 60s-70s before emissions systems came along. The water being cold or hot really does not matter.

On a small engine use a spray bottle and keep the engine RPM up on high throttle to prevent stalling. It only takes a couple of minutes.

Don't get carried away and think "more is better", it is not.