Forum Discussion

sccawildcat's avatar
sccawildcat
Explorer
Nov 02, 2014

Onan Marquis 5.5 gas no start

I have a 2007 Marquis 5.5 gas generator with about 250 hours on it. Used it 3 weeks ago without issue for about 5 hours over 2 days.

Went out this morning to remove freezable item and found the start button flashing. Checked the button on the generator and it is also flashing. The pre-heat lights up when holding but the unit will not start at either button. It has good fuel and oil levels and the house batteries run everything else. The MH has been plugged in to shore power since its last trip.

Any ideas where to start?

4 Replies

  • othertonka's avatar
    othertonka
    Explorer
    Nov 02, 2014
    sccawildcat wrote:
    Fixed, did a code check(push pre-heat 3x quickly) no codes flashed. pushed start and it ran!


    I am not aware of a pre heat button on the 5.5 gas generator. Mine has a prime button which runs the fuel pump when you push and hold down the STOP/PRIME button. Hold it for 20 seconds or more or until the pump quits clicking. Then push start button
  • sccawildcat's avatar
    sccawildcat
    Explorer
    Nov 02, 2014
    Fixed, did a code check(push pre-heat 3x quickly) no codes flashed. pushed start and it ran!
  • sccawildcat's avatar
    sccawildcat
    Explorer
    Nov 02, 2014
    I've read and re-read the service manual. It says nothing about a constant flash with no code. I've held it to pre-heat to get a code and all it does it a single flash every second or so.

    I just discounted the battery cable from the generator and left it off for 5 minutes with no change when re-connected.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,369 PostsLatest Activity: Mar 11, 2026