Onan QG 4000 RPM

[Glenn Briglio]

Originally Posted by Rich Biebel

They are my favorite model and I own 2 myself....

Most Every Class C Motorhome has one.....

I have one in my trailer and one in my Class C Motorhome....

They are not like the older 1800 rpm units for sure and are far less durable.

Older models were twin cylinder flathead engines that ran 1800
From a 4 to a 7 KW

20 years ago they started making their modern versions....

Single cylinder 3600 rpm....on the QG 4000's......The 5.5 and 7kw's are twin cylinder and nothing like the 4's....

Onan stopped making their own engines back then and everything they build uses an import built engine......No big surprise....

For those that don't know.....
A modern Onan QG 4000 has NO low oil shutdown....
If it runs low on oil it will at the very least seize up and usually much worse.....

The aluminum rod usually blows up and takes out the engine.

They only hold about 1-1/2 quarts of oil and it should be changed often.....and checked often.....No filter.....splash oil....

I saw more than one that blew up and really busted up everything in there.....changing an engine is not a good option so it winds up being trashed....

What oil do you like for this generator?