Onan 6.5 oil blow by and other issues


New Member
We just purchased our first our first RV about 2 months ago, its a 96 Itasca Suncruiser with very low miles on it (17k), and only 100hrs on the generator. As you could expect, the generator is a little quirky. Here are some of the issues and countermeasures I have done:

1. Under load, it was searching: Cleaned plugs and carb: seems much better now. :)

2. Microwave shuts off: noted that voltage is running approximately 130 and then drops to 120 while microwave runs...and then it shuts off. I have adjusted the low idle up, which helped, but now it shuts down really hard. :(

3. A lot of oil blow by: I have oil leaking out of the breather...when I opened the breather box, the filter was saturated with oil on the bottom and so was the box. I ran it without the filter on and I could see the oil blowing back. No resolution yet. :(

Any thoughts and recommendations would be much appreciated!



Senior Member
Onan 6.5 oil blow by and other issues

Gummed up carberator problems are very common with gensets that are nor run enough. Onan says that a set should be run under at least 1/2 load for a minimum of 1 hour each month. Your are probably on the right track. Now, run some carb cleaner through it and that should help. Adjusting the engine RPM is not good since an Onan links the voltage to the frequency of the power output. Normal at no-load is about 62 Hz and 130V. At full load it should be 59 Hz and 118V. On the oil problem, you need a better mechanic than I.