Have a good friend with Onan 5500 gas generator in her motorhome has had brushes changed twice from same place unit has less than 800 hrs and guys is telling her this isn’t unusual I’m calling B.S. she shows dogs so is very worried about reliability with motorhome full of clients dogs

It’s not BS and it can happen that often.

Clean the rotors slip rings as good and smooth as possible.

Put a flat washer under the brush holder to space it back more and verify the wires are on right.

Wires are marked F-1 and F-2 and F-1 goes on lower terminal on brushes if I recall right.

I usually check and confirm that in the service manual.

They will work either way but I put them on as shown in the manual.

The brush holders are easily heat damaged and I’ve seen brushes go many hours and just the opposite sometimes.

They cost $30 and can be changed in 10 minutes on a 5.5 or a 7kw.

I have serviced and repaired many of them and lots of dog groomers that have the 7kw versions.

Just serviced one for one of my oldest customers.

8500 hrs on her machine. I always check the brushes when they come in for anything.

Okay thank you I will look into that for her was just surprised first set only lasted 150 or 160 hrs she said and they are saying she should do them quite often but she said they are charging quite a bit

Was just with her this weekend and it burnt up another set I pulled them out to inspect this time has about 80 hrs on this set and it’s only burning up lower brush she said that’s how they all have looked

I've had this discussion many times

I'll repeat what I posted previously

Clean the slip rings and get them as smooth as possible and if there is any wear there that creates an uneven surface the brushes will rapidly wear.

They are arcing and it is generally on only one and creates heat and rapid wear.

Another issue is the brush is sticking in the plastic holder from heat


Back the brush holder up by putting a small washer under the mounting foot...


Other than that I have no good answer.

I Have seen them go hundreds to thousands of hours on various machines

Also have seen them toasted in under 100....

I've seen Generac portables eat a set of brushes in 5-10 hours.....

I just did a 4 KW Onan with 600+ and that's not unusual.....

This message has been edited. Last edited by: SCDIV1,

Thank you for the advice am going to look at those things you mentioned and she is ordering a spare set to have also

Rich,
Thank you for being the generator guru! You have worked through and solved many a persons issues on here and at the track!

I am glad to help but to be honest, I'm about used up from doing it and also doing some jobs at races I am at.

Sometimes I want to use a fake name and wear a disguise while I race....Hide in my trailer or MH

At MG a few weeks ago I changed a belt on a diesel in the rain......and was supposed to do a service on another diesel but never did that one....Both racers are good friends really and talked to me months ago about doing those jobs at the track

I'm working with someone now to try and fix a machine that so far refuses to work...It's most likely getting pulled out and brought to me to figure out.

I just fixed a 5.5 gas machine that seized a rotor bearing.....the racer who owns it is at New England Dragway running Stock

I am waiting for a van with a 7kw gas machine that quit.....probably a major failure...maybe a pullout and big repair....

Never a shortage of work this time of year....

I have to laugh Rich at the idea of you having to hide. Not that i mind and appreciate all the work
that once i bring the service truck to the track.
From AC partials to tire repairs to comp regen issues ETC. The one year i had to tell my good friend take over with the car. You are driving.
I'm busy I just can't do it. Racer helping Racer

Hopefully there will always be another day.

Once I was R/UP in Super ET at Etown and they sent letters out to us saying they overpaid us in the final. Asked for the $$ back....

The next week I entered using my friends name as driver......People were asking me where he was and I told them the story I'm not giving them the $ back....Etown was not my home track and I was not in the points. The other racer who won was and had no choice...

So I've already used a fake name to race

I think that was the day I almost hit the tree !!

My Vega got crazy at the launch ....If I would have hit the tree I'd have been in deep shyt....

How do you know to replace the brushes? Inspection? Performance? How difficult is this while in the generator rv compartment?

Leave all GPS's at home. Where is he hiding now. lol. The one year,a friend of mine asked me Hey. Is that your other service truck with the guy sleeping in it? What service truck? Here come to find out he was scouting for work during the event
Never even heard of the company from this area.

Almost identical service trucks with only the DOT number on the door.

Have at it.All the power to him.

quote:

Originally posted by Bucky:
How do you know to replace the brushes? Inspection? Performance? How difficult is this while in the generator rv compartment?

Brushes wear out your machine won't run.

Old machines more difficult than new but still no big job on gas units...

Some Diesels are much harder......brain surgery is easier....

[QUOTE]Originally posted by SCDIV1:
I've had this discussion many times

I'll repeat what I posted previously

Clean the slip rings and get them as smooth as possible and if there is any wear there that creates an uneven surface the brushes will rapidly wear.

They are arcing and it is generally on only one and creates heat and rapid wear.

Another issue is the brush is sticking in the plastic holder from heat


Most idiots just stick in new brushes. If you dont give them a good surface on the slip rings they wont last. Just did a 7K diesel, red scotchbrite on a pencil made quick work. Start engine, it runs for as long as the computer takes to find no power, and do it again and again.

I did the job Friday for my wife’s friend found lower slip ring very black leaned with paint stick and fine sand paper got them both clean and smooth also found old brushes were worn on an angle found if you don’t hold the brush holder level while you tighten it hole assembly tilted and my guess would jam brushes again I want to thank Rich for the advice and will keep an eye on them

It doesn't take much to create a problem in there.

Cheap plastic brush holder and like a lot of things in those machines the heat gets to them...

The 7KW version is the same engine running at a faster speed. Makes more heat and wreaks havoc on some parts over time....