Onan LP Generator hard to start

[Darryl]

I have a 6.5 Kw Marquis LP genset in my motorhome that has suddenly become more difficult to start. Once it starts, it runs and performs great. It has always taken longer than I thought was normal (about 15 seconds of cranking), but now will not even start unless I go out and place my hand over the air intake for a couple of seconds. Then it starts right off. After discovering this, I also discovered that it will start within about 4 seconds of cranking it over (instead of the 15 it normally took).

If this were a gasoline model, I'd say the choke is not working. However, I don't know how these LP units get their fuel delivery, if they have a special start circuit that delivers extra fuel for starting, or if they even have a choke. I've watched the carburater and after about 3 seconds of cranking, the throttle opens fully. I recently changed the spark plugs on it and this didn't make a difference.

This unit is faily low hours (less than 200), but since I've had this motorhome, it gets run an hour or more every month. In the summer, it powers the A/C while going down the road --- usually 3 or 4 hrs at a time. No other problems.

Does anyone have experience on these LP units that could point me in the right direction?

["007"]

Darryl, in this PDF theres mentioned of a electric fuel solenoid and a " side draft mixer with demand regulator" as with a gas furnace or water heater you need correct air mixture for proper air LP mix. When you place hand over vent intake you change mix.
See your manual it may have info on how to adjust the side draft mixer.

[Darryl]

Thank you. I'll take a look at this.

DH