Diesel Generator Misfire Onan with Kabota Engine

[hypoxia]

I have an intermittant misfire on my Onan 12.5 Kw generator, HDKCB Spec B, Kubota Engine, 1100 hours.

It generally runs fine but once it misfires it continually misfires randomly, not in a regular pattern. It usually doesn't shut down but it does show a code for a shutdown due to the 0.5 second limit.

I did the fuel flow test which it passed by double the low limit. I changed the filter 6 months ago and due to the flow test think it is OK. The pump is pumping but may be worth changing as there is a possibility it is intermittant.

Next is the Governator Actuator which I have not tested, then the Control Board according to Onan.

Anyone have experience with this problem?

[twinboat]

When you did the flow test, did you watch for air bubbles in the fuel. A slight suction leak can cause the misfires.

[hypoxia]

No air bubbles & the line looks good.

[hypoxia]

It's running fine now. I talked to an Onan mechanic who also suspects bubbles in the fuel.

It did have a 36 code in the memory; 0.5 second miss causing shutdown.

The Onan guy suggested that since there's no way to know if the code is recent or from years ago, to disconnect a wiring harness & start it up creating a 27 code. Reconnect it and if the 36 code returns I'll know it just happened.