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frankdamp's avatar
frankdamp
Explorer
Mar 11, 2013

Onan 5.5 HJAB-901A starting problem

We don't use the generator very often, other than exercising it to prevent varnish build up in the carb. It's in an '02 Georgetown.

I had used the drain screw to empty the float bowl when we parked it in early November2011. That December I had an angioplasty op and I didn't get to trying the usual monthly generator run until about April 2012. When it started then, it ran for about 2 seconds and shut down. I've been fiddling with it ever since.

Son-in-law and I really got into trouble-shooting last weekend. We found the electric fuel pump was intermittent - sometimes it would prime but most times would not. We replaced the pump with an Airtex, following the advice in an old thread on RV.net which a google search had found. We were confident we'd fond the source of the trouble, but we hadn't.

I'd like to get some ideas. It looks to us like there's somethiong in the control box that isn't working properly. The fuel pump now primes an empty carb and the engine starts. When the governor lever starts to move, the engine coughs and dies (about 2 seconds after it atsrts).

The entire generator is very clean, no signs of dirt anywhere. It has a total of 51 hours on the Hobbs meter. After it dies, as described above, we get fault code 32, which is "Engine didn't achieve correct cranking speed". We think it's cranking as well as it did when we first bought the RV, so we're beginning to wonder whether the RPM sensor is not working and the "brain" giving a "shut-down" command.

My questions are:

1. Where can I find a schematic of the innards of the controller?

2. Where is the RPM transducer?

3. Should I take the carb off and clean it anyway, just in case it's gummeed up.

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