Onan KY broken valve spring

Wayne Dohnal wrote:
This story could have a happy ending. The responses above gave me a few ideas of things to check out. After inspecting what I was able to without pulling the head, including seeing a little bit of the valve and piston through the spark plug hole and pressurizing the cylinder with compressed air, it looked like there is a chance that nothing was seriously damaged. I ordered 2 new valve springs ($30 each!) and popped them on. Lo and behold, the other original spring was also broken. Ran the air conditioner from the generator for an hour today and it all went well. Only time will tell, but there's a chance that the thing is ok now.

The generator was built in 2008 in the middle of a period where there was an epidemic of broken valve springs in the Microquiets. Did Onan maybe try out a new Chinese supplier and get burned? A lot of these units were fixed under warranty. I paid the penalty for not running up a lot of hours before the warranty was out.

Here is a good link to have. Service Manual for KY Microlite 4000 series

The below comes from page 1-2 (page 7) of this PDF: http://www.cumminsonan.com/www/pdf/manuals/981-0503.pdf

3.6 = 3600 watts
KY = Product family
F = remote startable
A = voltage and Freq. (120V, 60Hz)
261120 = Specification number
L = Specification letter



C = build month: March
08 = build year: 2008
0 = MFG'd in Fridley, MN
167118 = Active Serial #