Onan 12.5 kW HDCAB Generator Fuel Injector Service

[Lee Smith]

The Periodic Maintenance list, per the Onan/Cummins manual, states that the fuel injectors service is to be performed at the 1,000-hour service or at least every five years. I just bought my 2004 Signature in April of this year. My generator is 18 years old, and I have no records to show what has been serviced.
I am scheduled to have the 1,000-hour service done next week at the only nearby Cummins Service Center. Unfortunately, they left the fuel injector service off the estimate and when I asked to have it included, they responded "Due to equipment constraints we are currently unable to perform the injector service at this time".  Sounds kind of odd plus the fact that they did not disclose ahead of time is somewhat troubling.

Any thoughts?

Thank you,

[Frank McElroy]

1 hour ago, Lee Smith said:

The Periodic Maintenance list, per the Onan/Cummins manual, states that the fuel injectors service is to be performed at the 1,000-hour service or at least every five years. I just bought my 2004 Signature in April of this year. My generator is 18 years old, and I have no records to show what has been serviced.
I am scheduled to have the 1,000-hour service done next week at the only nearby Cummins Service Center. Unfortunately, they left the fuel injector service off the estimate and when I asked to have it included, they responded "Due to equipment constraints we are currently unable to perform the injector service at this time".  Sounds kind of odd plus the fact that they did not disclose ahead of time is somewhat troubling.

Any thoughts?

Thank you,

That's an interesting service requirement to check injectors at 1,000 hours so I looked up the maintenance on my 10kw generator and sure enough there is a maintenance item to check the injector pressure and spray pattern every 1,500 hours.  From what I read it's more driven by an EPA emissions check to be sure the injectors are operating properly for low emissions.  The likely reason this isn't done is that it's more cost effective simply to replace the injectors if they go bad and the generator starts smoking.

[Ivan K]

My 1999 12.5kw with Isuzu truck motor only lists checking Injector pressure at 1500 hrs, per EPA. Just as Frank said. In my opinion, 1500 hours equals roughly 75k miles in a vehicle, don't know anyone who really does that unless there is a problem, eventhough it should be quite simple to do with only 3 pumps.

[Lee Smith]

Okay so in further checking I find that it is apparently not necessary to have the injectors serviced unless there is a problem. I switched from the local Cummins shop to an RV Service center that I used a few years ago when I had a Class C. They put me in touch with their 78-year-old part time generator mechanic and he explained in detail how he determines if the injectors need service. Does not seem likely they will. He recommended the use of "Sea Foam" to clean the injectors if needed. He said he could probably get the entire service done in one day. I will take it in for service on Wednesday. I will post how this works out. 

I am very thankful for the help I received on this great forum.

Please see my water pump post for a very similar follow-up.

[Ivan K]

I have never used Sea Foam in diesel engines but occasionally I dump a dose of Diesel Clean into the tank and that makes it everywhere.

[FrayJo]

When I was reading it seemed unusual service requirement to check injectors every 1,000 hours for me too. So in my generator maintenance that I conducted last summer, listed to check injectors every 1,000 hours. I did not delve into the essence of what was being checked, I decided to trust the professionals. I guess your right this isn't done is that it's cheaper to simply replace the injectors if they go bad and the generator begins smoking.