Onan Generator Choke Adjustment

Last spring I did a tuneup on my Onan 4k Micro-Quite generator. This improved the starting and running of the genney.

However,  when starting, it seemed like I had to crank the generator for a long time, especially when cold.  Cranking times would be 20-30 seconds, and if it was real cold (below freezing, I’d usually need to crank for 20 seconds, it would catch and act like it tried to start.  I’d let it sit for a 10 seconds,  then on the second crank it would usually start.

I read through the 4000 MicroLite Service Manual and found a procedure for adjusting the choke.  The procedure calls for visually verifying the position of the bi-metal strip through a small opening in the choke control. On mine the only way to look through that opening is to remove the generator, then remove the entire cover.  It ain’t happening.

Its 30 degrees outside. Perfect for adjusting and testing the choke.

Before starting,  I briefly cranked the engine and watched the choke.  What I seen was the choke would get blown (sucked) open as the engine cranked.   I pulled gently on the chokes connecting rod to see how much resistance it had,  very little.  It seems like it needs a little more.

Initial adjustment points to about 10-11 oclock
New adjustment, points to about 8-9 oclock

I decided to simply move the adjustment until I felt comfortable with where it was at. I loosened the adjustment lock screw (it wasn’t very tight to start with!!!)  and turned the adjustment while pulling a little on the connecting rod to see how much force was being required to hold the choke closed.

I had turned it about 90 degrees CCW, and this felt good.

I tightened up the lock screw,  then attempted to start the genney.

Choke fully opened as genny warmed up.

WOW – It cranked for about 2 seconds and started right up.    Now thats the way its supposed to be. 🙂   I let the genny run for about ten minutes to make sure the choke was opening,  no problem.

Over the next few days,  I’ll go out and try the genny.  Its supposed to get down to about 10 degrees tonight so I’ll give it a try tonight.

Below are links to the various manuals for the Onan MicroLite:

SERVICE MANUAL

OPERATIONS MANUAL

PARTS MANUAL

FLIGHT SYSTEMS TROUBLESHOOTING

 

2 thoughts on “Onan Generator Choke Adjustment”

  1. same problem seems to take longer to start now and only has 55hrs
    ill try this adjustment
    thanks
    Kerry

  2. I made the same adjustments ….. starts like its supposed now….
    you should write a book you know (or buy another motorhome) lol
    all the problems that you have had ..most other people have had also, and I thank you so much for sharing it with other owners…
    is there any way other people can post pictures?

    Kerry
    2002 coachman mirada 30 ft
    66,000 km (39,000) miles
    thanks again

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