Onan Generator Carbon Knock

[Rich Biebel]

An old trick that does work........WATER......While the engine is running feed it some water thru the carbs air horn......Steam cleans it....and it does work.

I worked in an engine machine shop for many years. If you see how hard the carbon deposits are to remove from heads of all kinds you'd know there is no magic chemical that is going to remove this stuff..

I rebuilt many Mack cylinder heads......The carbon buildup in a diesel intake port is so heavy it can close the port down almost completely shut. The old hot tank does not cut thru this stuff since it's so thick.....

I literally chipped it out with a hammer and chisel before hot tanking the heads....


The carbon buildup in an Onan flathead is nowhere near that bad but it's still the same stuff....unburned hydrocarbon.....COAL....
Superman could make it into a diamond.....LOL
I am sure of it....I saw him do it on TV.......

[Tom Goldman]

Originally Posted by Rich Biebel

An old trick that does work........WATER......While the engine is running feed it some water thru the carbs air horn......Steam cleans it....and it does work.

I worked in an engine machine shop for many years. If you see how hard the carbon deposits are to remove from heads of all kinds you'd know there is no magic chemical that is going to remove this stuff..

I rebuilt many Mack cylinder heads......The carbon buildup in a diesel intake port is so heavy it can close the port down almost completely shut. The old hot tank does not cut thru this stuff since it's so thick.....

I literally chipped it out with a hammer and chisel before hot tanking the heads....


The carbon buildup in an Onan flathead is nowhere near that bad but it's still the same stuff....unburned hydrocarbon.....COAL....
Superman could make it into a diamond.....LOL
I am sure of it....I saw him do it on TV.......

Rich, you are OLD to remember that!!

[Rich Biebel]

Tommy I am old but still pretty spry as you well know......
Who else my age rides a bike for hours on end when racing NHRA events.....Nobody thats who......LOL

I loved Superman.....The dude squished the rock and made a diamond and put in some statue to keep the natives happy......Well thats how I remember it anyway...... .....

I Might run the S/C series this year.....Matt's workin on me...I feel the need for speed......LOL

See ya soon my friend.....Rich

[Peter Ash]

And if they glaze the rings from too much idling/low load time, a little bon-ami down the intake will rescuff the rings and cylinder walls. Used to be supplied by Caterpillar with a part number. Also a long time ago.

[Rich Biebel]

Bon Ami was supposedly used in the early to mid 60's on Pontiac motors in dealerships that had some ring seal problems. Add some to the oil....run it for a while and than change it. They might have been using chrome rings.
Was a little before my time but some guys told me about it at a Pontac dealer I worked at in the '70's as a line mechanic....

[Paul Wong]

Is there a way to prevent this carbon build up in this design of generator? should you run it out of gas when you shut it off?

[Mark Ruset]

Hey Paul from all the research I've done this it seems to be a common occurence. What I've read, running the generator as often as possible under a load will lessen the possibility of carbon build up. If you are running down the road in the motor home have the generator running with a load applied, such as the microwave oven, for a period of time. I can say this that after I removed the heads to clean the carbon build up the generator runs smoother than it ever did before and with much less noise.