Onan Generator

[DothanAntelope]

Hello All. We have a 2004 Tiffin Allegro Open Road that we have had since new. Gas engine that has on 23k miles on it. Body is in good shape. Here is my question. Our Onan generator has over 3200 hours on it. We used this coach mostly for tailgating in Tuscaloosa on football weekends, hence the high hours on generator. The generator stopped and I had it checked by a local shop who told me the motor was “ shot”. What are yalls opinion? Should I try to get this engine rebuilt or buy a new one? Harbor freight has a 7k Onan for 5100 dollars. 115 dollars to deliver.
Thanks in advance.
Tim

[Gjac]

I would check the simple things first if you haven't already. Does it have spark when you crank it over? Is fuel coming out of fuel pump when you disconnect it from carb and hit the start button? Are you batteries fully charged?

[koda55]

When my Onan gas 5500 died it was low on oil.

[Rgtopda]

michaelhebert1986 I had the same problem with shutting down after 30 minutes while in Talladega..Put a fan under it and it kept running without a problem...So when I got home I took it to my guy that works on the generators and he said it was my batteries...I thought he was nuts..However I put two new batteries and never had a problem with it shutting down. It seems when the generator is trying to charge the batteries and they wont charge it overheats the sending unit that powers the batteries..I know that sounds weird but BAM it worked

[wa8yxm]

Jim@HiTek wrote:
It's odd that you now have to dig three pages deep in Google search to find them now days when they use to be the 3rd one down back in 2005. All those other companies paying lots of money to be higher in the search results.

Google gives top billing to paying clients. Always has but now it's getting worse as more and more companies find they can pay for better listings..

[Jim]

I don't know where that '3200 hours and it's no good' info is coming from, I've been reading for years that an Onan generator is designed for 10,000 hours before a major overhaul is needed. I'm pretty sure that's in my owners guide too.

If your genset was running fine, and just stopped? Mine did the exact same thing. One of the end shaft bearing balls in the ball bearing broke and boom! engine stopped dead. Shop in Portland had it out and replaced for $640.

You don't tell us much about what happened before and after it got to that point like did you try to restart it? What happened if you did? That could help with a more accurate evaluation.

But if it were me, I'd remove my generator from that shop and tell them thanks but no thanks.

Here's the goto guides for analysing your Onan's symptoms, very handy resource with their complete testing guides: Onan Troubleshooting

It's odd that you now have to dig three pages deep in Google search to find them now days when they use to be the 3rd one down back in 2005. All those other companies paying lots of money to be higher in the search results.

[wa8yxm]

On many RV's the major cost is removal and replaement.. Though the generator itself can be expensive.

IF the shop has the unit out of the RV I'd look to a shop that can restore the engine,, That seems like Well let's see 3200 times sixty 192000 "Miles" on as it were (60 MPH) many car engines now last 2x that long with decent care.

[A_Good_Cigar]

DothanAntelope wrote:
Sorry it was Northern Tools not harbor Freight. The generator was running for about an hour and just stopped. Under no particular heavy load. I personally changed the oil and filter on a regular basis.

Ok, since then will the engine crank but not start? At least 1/4 tank of fuel & verified engine oil topped off? Is the start/stop switch flashing any code numbers? You're still not giving us enough information to help you, but we at least need know what wattage the generator is! 5500 Marquis gold?

[dougrainer]

michaelhebert1986 wrote:
Also,

I haven't had that problem. My problem with the Onan 5500 Marquis Gold onboard generator is that with the cover on and the latch closed, the generator runs for 20 minutes and then shuts off. After 30 minutes or longer, it will start back up and do the same thing, over and over again.

It does this with a load or not and either plugged in to the 50 amp receptacle or not.

Today I tried taking the cover off and leaving the hatch open and it has been running for 55 minutes at the time of this post without any problems (I have the front AC on, several lights turned on, and a box fan plugged in.

Not really sure what the problem is now. At first I thought it may be a fuel issue. Maybe the fuel pump gone bad or a crack in a fuel line. But since it was ran now for twice the length it was before I purchased the motorhome (2 weeks ago), I am stumped.

Any suggestions?

I would check for overheating. Make sure the compartment mount plate has the required holes for the air flow to cool the engine. And the cool air can flow correctly in and out. Even tho the OEM's do not do this now, because the design of the Onan cooling system has changed, the access door on the RV used to be 1/2 screen to allow fresh air in. But, having that fresh air can help. Doug

[michaelhebert19]

Also,

I haven't had that problem. My problem with the Onan 5500 Marquis Gold onboard generator is that with the cover on and the latch closed, the generator runs for 20 minutes and then shuts off. After 30 minutes or longer, it will start back up and do the same thing, over and over again.

It does this with a load or not and either plugged in to the 50 amp receptacle or not.

Today I tried taking the cover off and leaving the hatch open and it has been running for 55 minutes at the time of this post without any problems (I have the front AC on, several lights turned on, and a box fan plugged in.

Not really sure what the problem is now. At first I thought it may be a fuel issue. Maybe the fuel pump gone bad or a crack in a fuel line. But since it was ran now for twice the length it was before I purchased the motorhome (2 weeks ago), I am stumped.

Any suggestions?

[michaelhebert19]

What does the generator make sound wise when you try to start it?

[ksg5000]

If it were me I would buy a used one - plenty of low hour onans available - my next choice would be rebuilt which will save you 3K. That's assuming that your current Onan is actually caput.

[gbopp]

Will the engine turn over, or is it seized?

[rgatijnet1]

A generator engine just does not die without some prior symptoms. Was it using a lot of oil when you last used it? Did it seem to take a long time to get it started when cold, indicating low compression?
If the engine was running fine and just shut down, it may be something as simple as a clogged/leaking fuel line. Low oil shutdown, etc.
As suggested, take it to a QUALIFIED shop and have then do a complete diagnosis of the issues and then make a decision as to what needs to be done.

[dougrainer]

You are looking at about $5500 to buy a new onan. I would call a few independent Gen shops and ask what they would charge to either rebuild the engine or just short block the engine. Gensets have 2 sections. The ENGINE and the GEN part. Usually, a qualified shop can rebuild or replace just the engine for less than $2000. Saving you $3000. Onan Gensets are designed to be rebuilt, unlike the disposable ones you get at HD or Lowes or even Harbor Freight.