Forum Discussion

Ed_Manifold's avatar
Ed_Manifold
Explorer
Nov 07, 2021

7500 diesel generator

Just got back from a 2000 trip. Had trouble with my generator, I think that it is self inflicted. The generator will start after much trying and only run for a couple minutes and then shuts down and when it does run its very rough. About a month ago I serviced it which included changing the fuel filter. When I started it after the service it was hard to start but finally did. I figured that air was in the lines and worked its way out after it started and ran. I think my problem with it now is that I still have air in the fuel lines. My question is how do I bleed the air out? The generator is an Onan 7500. Thanks for your help.
Class A
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Nov 07, 2021
    The blinking is a code that indicates the problem area. Read up on the codes and decipher the code.

    Air leaks are due to suction and may not show any signs of diesel.
  • Ed_Manifold's avatar
    Ed_Manifold
    Explorer
    Nov 07, 2021
    Thanks for replies, changed the air filter, I did get blinking when the generator stopped and I will check the spark arrestor. I do have a new fuel filter coming and I will change just in case the one installed was faulty. After I initially changed to the new filter I did have a leak from the largest fitting but was able to tighten it and the leak stopped. Thanks again for the help.
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Nov 07, 2021
    larry cad wrote:
    Been running my 7500 for 16 years and never had to prime it.
    X2 for my seven years. But if it ran better for a short time after priming that might be useful information.

    OP The input fuel line etc is a closed system and unless leaking will not normally have any air except when the tank is low or maintenance.

    IF your problem is air in the fuel then my first suspect would be as a result of the maintenance, but another issue could have developed.
  • larry_cad's avatar
    larry_cad
    Explorer II
    Nov 07, 2021
    Did you change the air filter when you changed the fuel filter?

    Also, have you cleaned out your spark arrester, per the instructions in the manual?

    Been running my 7500 for 16 years and never had to prime it.
  • FloridaRosebud's avatar
    FloridaRosebud
    Explorer
    Nov 07, 2021
    My genny is gas but I'm having a similar problem. My error code on the switch says the engine stopped without any input from the control or electrical system - IOW, a fuel issue. I disconnected the gas line at the carb, tried to start, and the fuel only shot out maybe 6" to a foot, and not very strong. My rig is 16 years old, so I've got a new fuel pump on order. (I should add it also stops when I'm going down the road, but not sitting still, and my fuel filter is new) The plan is to blow out the lines into the fuel tank, and replace the fuel filter (again) and fuel pump.

    Al
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Nov 07, 2021
    Possibly something developed a air leak. On a 19 yro rig it could be a leak due to age of hoses or fittings or improper tightening, etc. Normally just priming and running will resolve any air.

    Do you have adequate fuel? Gen fuel pickup is higher than the engine for obvious reasons.

About Motorhome Group

38,707 PostsLatest Activity: Jan 05, 2014