Onan running runs rough

[ron preston]

My 6000 W power drawer starts ok but runs rough, it will idle for awhile
then misses, the governor opens up the throttle to full , it will almost
die then come back and idle rough, backfire through carb etc. , put in
new plugs, trimmed insulation on plug wires , and rebuilt carb resulting
in little change. Points look OK
Any advice would be appreciated.
Thanks
Ron Preston , 75 Glenbrook, headers,
flowmasters, Alcoas
San José,, CA

 

[jim miller]

>
> My 6000 W power drawer starts ok but runs rough, it will idle for awhile then misses, the governor opens up the throttle to full , it will almost
> die then come back and idle rough, backfire through carb etc. , put in new plugs, trimmed insulation on plug wires , and rebuilt carb resulting
> in little change. Points look OK

Try jumpering battery+ to coil+ to bypass the control board. If it still acts up then remove the jumper and go after ignition issues in the order below. Stop after each one and re-test the engine.

1. Put a ignition test light in series with one of the plugs and confirm that you indeed have an ignition issue. The Onan runs slow enough that the naked eye can see lost sparks.

2. Burnish the points with a proper burnishing tool….or simply replace them. I know you said they “look OK” but this is a very important step.

3. Disconnect the AM-radio noise filter from the side of the coil.

4. Replace the coil condenser. Condensers are notorious failure items.

5. Hold the points wiper away from the plunger. Use a pair of needlenose pliers (gently!) to ensure the points actuator plunger moves up and down freely with no sticking or binding.

6. Try another coil.

If you have a points box that is accessed through a side panel then make sure to note EXACTLY where the points were adjusted so that you can put them back in with the identical setpoint. The later top-access points box is much easier to work with and will maintain the points setting without the need to be marked.


Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH

 

[john r. lebetski]

What does "trimmed insulation on plug wires" mean?
--
John Lebetski
Woodstock, IL
77 Eleganza II