Generator starting problem

alale11

Junior Member
#1
I have a 2.8 Onan microlite RV generator when its cool it will start, and run until I shut it off, once I shut it off, it will re-start if done within a few minutes, but wait 15 or more minutes, and it will not start for at least a couple of hours. I have replaced the ignition coil, and the spark plug, since I do not get a constant spark when it fails to start, but, just one spark when the start button is released. I have checked the magneto voltage at the time that I am not getting a constant spark, and it reads 31 volts which is within normal range when cranking. At this time I have run out of ideas, maybe someone out there has had a similar problem and can help me.
Thanks
Al
22
 
#2
There are about 4 possibilities. Bad circuit board, bad voltage regulator, dirty slip rings, or low oil pressure/or bad oil pressure sending unit. Probably the most common no-start problems are fuel supply, so change the inline fuel filter and make sure fuel flows freely. Cracked fuel lines are a common problem too, allowing the genny to suck air along with fuel.
 

alale11

Junior Member
#3
Well it seems that non of those 4 possibilities is the culprit, since I have already replaced those parts with the exception of the voltage regulator, which I have no problem the voltage and frequency is constant no matter what the load. Parts replaced: control board, ignition coil, spark plug, fuel filter, and air filter. and the problem has not changed one bit. So I think is time to bring in the experts.
 

alale11

Junior Member
#4
Just to update everyone that read the original post. The problem was the magneto, even though I was told that if I was getting between 15 and 50 volt A/C the magneto was good, well if was not. Replaced it, and it runs and starts, just like when it was brand new.
Live and learn.
 
#5
One tip I've learned over the years is to make sure to exercise the generator at least once a month especially when your RV is just sitting for a while. I use a great program on my computer called Automotive Wolf vehicle maintenance software to track all the maintenance on my RV including the generator. Basically I run the generator once a month for about 45 minutes with no load and then 15 minutes with the AC on high. Ever since I've been doing this I have not had any issues with my generator. Letting it sit for an extended time without running it will cause problems.
 
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