microlite 4000 starting

[rsusag]

I am having trouble finding instructions on starting procedure for my Onan microlite 4000. When I push the start switch either in the motorhome or on the generator itself it appears that it is ok to hold the switch in the start position. I mean it's not like a car ignition switch where you should let go once started. what exactly is it doing besides engaging the starter motor? The gen starts but stops right away. By continuing to press the switch is it getting extra fuel to get it going? Thanks from a newbie.

 

[Alfa38User]

Nah, the fuel pump is electric, external and runs all the time. (It could be pumping too much air and too little fuel if there is a leaky rubber hose though). When starting the generator, it has built-in safety measures like an oil pressure check, and a check that it is actually generating 120V AC. Those checks are disabled when the start switch is in the start position. If the engine quits when the start switch is released, it is usually because one of those checks is not being satisfied. On many Onan generators there is a method of narrowing down what that problem is by the flashing lights on the engine panel. The manual should have those instructions.

No manual?? try here: https://www.cumminsonan.com/www/pdf/manuals/981-0503.pdf

 

[cgmartin]

rsusag, instead of continuing to press the start button, you need to hold the button in the stop position in order to prime it. Hold it down for about 4-5 seconds, then press the start button, then release once the motor starts. That is the procedure for starting the microlite 4000. If the generator is already hot an has been running, it will almost always start by pressing the start button, but when it is cold and has not been running, you need to prime it.

 

[rsusag]

Update on Microlite problem. On my Microlite 4000 which is a 1999 year model there is no priming ability. It has an automatic choke which was set to an extremely lean setting. We adjusted it and it started fine. It also would quit after 10 to 30 minutes. I finally after reading about this problem went ahead and replaced the fuel pump. I pried the old pump apart and found that the rubber parts were degraded from gas with ethanol. I bought a pump from a cummins store so am certain it has parts that can withstand the ethanol. Also thanks to a youtube video I replaced the pump without too much difficulty. Ron