I have a Genarac in my Gas Georgtown 37ft Class A that is 6k Watt. My Brother in Law is selling an older Toyhauler and since he won't get any value out of his Onan 5500 Marquis Gold I was thinking about seeing if he would swap. My Generac seems to have issues once in awhile and seems harder for me to get parts for. Size wise they look the exact same. Is this something I could do myself as far as swapping one for the other or is it pretty involved? Like needs to be done at the dealership? Or is it not worth the trouble? I have always loved all the Onan 5500's I have owned. The Generac I don't really love.

We do this allot with ENG news trucks, and the only thing we ever pay attention to is the size of the box since it and generators evolve over the years depending on what was installed originally. After that its blower venting and exhaust. If you guys are mechanically handy at all and it fits in the existing box, you're 90% there already

So my Brother on law says he would do it. So what do you think should I make the swap? I'm going to go take a look and see how hard of a deal it's gonna be to make the swap first. I don't want to pay for a dealer to do it so it would have to be something I could tackle. What do y'all think?

If the mounts can be fitted and the ventilation is adequate it should be a good upgrade.

Your generator swap should'nt be a very hard job at all. As long as the fuel line and power lines to the transfer switch reach, its mostly a matter of reconnecting. The exhaust may need to be modified or replaced but other than some heavy lifting, I don't think you'll have any problems.

Based on my experience with the Onan 5500 Marquis Gold, I'd say don't waste your time, unless you have significant problems with your current unit or the Onan has EFI. My MH has the 5500 Marquis. It's an '02, which means the generator is probably a 2000 model.We bought the MH in 2010. The generator worked fine the first 2 years we had the rig, though we didn't use it much as we tend to stay in FHU campgrounds. In late 2011, I had cardiac problems and was out of service for a couple of months. I didn't get to do the monthly "exercise" of the generator for about 10 weeks. It hasn't started since.It backfires like crazy when I try to start it and spits out great gouts of white smoke. I suspect the problem is with the carburetor. If the one you're considering is EFI, go for it. If it has a carb, expect problems, particularly if it hasn't had regular exercise. Ours has about 70 hours on the meter - it was around 55 when we got it. I figure 55 hours in 8 years with the original owner was probably all the "monthly exercise" time.Since we don't use it, I've been less than diligent in trying to fix it. I'll have to figure things out this year, as we plan to sell the rig in the fall. Having a dead generator tends to dissuade folks from buying!

What's involved to swap my Generac to Onan? | Good Sam Community

Bendare2
Explorer
Oct 23, 2015
lacofdfireman wrote:
Well on an update I messed around to long and my brother in law ended up selling his trailer with the Onan in it. I missed out. Still having issues with my Genrac. It's still garbage. Have it in the shop as I speak getting it worked on...

But a new Onan is $4500 before install. OUCH.... Isn't there a Motorhome graveyard somewhere where you can pick up an Onan for cheap? There has to be a ton of them out there..

http://visoneautomart.com/

Visone......in Kentucky.......MH graveyard.....got a lot of coaches on their lot.
Google them.......I'll try to find my link.
I had coach burn and they have it there.....that's how I know about them!

Good luck........Ol'Ben
Tinstar
Explorer
Oct 22, 2015
There's a ton of them on eBay.
wolfe10
Explorer
Oct 21, 2015
Might start here: http://craigslist.thingweb.com/results.aspx?cx=partner-pub-2437314722686902%3Ayxqqljgzey4&cref=http%3A%2F%2Fcraigslist.thingweb.com%2Fcse%2F&cof=FORID%3A10&ie=ISO-8859-1&q=onan&sa=Search
lacofdfireman
Explorer
Oct 21, 2015
Well on an update I messed around to long and my brother in law ended up selling his trailer with the Onan in it. I missed out. Still having issues with my Genrac. It's still garbage. Have it in the shop as I speak getting it worked on...

But a new Onan is $4500 before install. OUCH.... Isn't there a Motorhome graveyard somewhere where you can pick up an Onan for cheap? There has to be a ton of them out there..
glamisorbust
Explorer II
Jul 03, 2015
I would go ahead and replace the generac. This is an old thread, surprised you haven't done it already. It really shouldn't be that big of a deal if you're mechanically inclined.

Maybe just buy an onan off of craigslist. There are tons of them for sale. Onan is the best generator manufacturer out there. I have a 7500 quiet diesel in my coach. I absolutely love it. I knew someone that had a toyhauler with an onan 5500 and it was extremely quiet. Go for it! Generac sucks!
lacofdfireman
Explorer
Jul 02, 2015
mc.cc wrote:
glamisorbust wrote:
I had a generac primepact 50G, 4800 watt gas generator and absolutely hated it. Worst generator i've ever owned. There were tons of problems with it. First one was the arm that controls the engine speed broke(made of very thin steel)while I was on a week-long camping trip, boondocking and had no power for most of the trip. Made the trip miserable. So I welded it back together and away I went. Then, the carburetor started leaking from the float bowl rubber gasket. Guess what, can't buy parts for the carburetor. But you can buy a new carburetor for lots of money. Also, this genny was VERY hard to start all the time. Crank, crank, crank, and sometimes crank some more before it would actually start. It was all dialed in and tuned up, just a steaming pile of junk. All this with a full tank of gas, clean filters, topped up oil, etc. Never again.

I had the exact generator with mostly the same problems. Could not keep it running while driving down the road either. It was the worst experience I ever had. Dealing with the authorized Generac dealer was a nightmare as well. Finally paid for a brand new onan 5500 installed. 600 hours later, it is still running perfectly.

I know this is an old thread but what did the new Onan cost you and to have it installed?

Also still have the Generac and still have issues keeping it running. I'm really considering replacing.
mc_cc
Explorer
Aug 30, 2014
glamisorbust wrote:
I had a generac primepact 50G, 4800 watt gas generator and absolutely hated it. Worst generator i've ever owned. There were tons of problems with it. First one was the arm that controls the engine speed broke(made of very thin steel)while I was on a week-long camping trip, boondocking and had no power for most of the trip. Made the trip miserable. So I welded it back together and away I went. Then, the carburetor started leaking from the float bowl rubber gasket. Guess what, can't buy parts for the carburetor. But you can buy a new carburetor for lots of money. Also, this genny was VERY hard to start all the time. Crank, crank, crank, and sometimes crank some more before it would actually start. It was all dialed in and tuned up, just a steaming pile of junk. All this with a full tank of gas, clean filters, topped up oil, etc. Never again.

I had the exact generator with mostly the same problems. Could not keep it running while driving down the road either. It was the worst experience I ever had. Dealing with the authorized Generac dealer was a nightmare as well. Finally paid for a brand new onan 5500 installed. 600 hours later, it is still running perfectly.
JoeH
Explorer III
Aug 27, 2014
I would do the swap, the Onan is probably much quieter. While you are doing the swap, take off the carb and clean it good, then when you install the genset, put an inline fuel shutoff ( get at a lawn mower shop) .... when you are putting the unit away after a trip, start the genset, get it warmed up, then shut off the fuel via the shutoff valve you installed. This will pretty much empty out the carb bowl and help avoid gum up issues and corrosion from the ethanol gas sitting in there for a long period
vegasfoodguy
Explorer II
Aug 27, 2014
lacofdfireman wrote:
This is with fuel full or above half. It doesn't matter which. Maybe I should take off the carb and clean. Or is there a better way to do it?

Gas can with gas and Seafoam. Then Seafoam in fuel tank.
glamisorbust
Explorer II
Aug 27, 2014
I had a generac primepact 50G, 4800 watt gas generator and absolutely hated it. Worst generator i've ever owned. There were tons of problems with it. First one was the arm that controls the engine speed broke(made of very thin steel)while I was on a week-long camping trip, boondocking and had no power for most of the trip. Made the trip miserable. So I welded it back together and away I went. Then, the carburetor started leaking from the float bowl rubber gasket. Guess what, can't buy parts for the carburetor. But you can buy a new carburetor for lots of money. Also, this genny was VERY hard to start all the time. Crank, crank, crank, and sometimes crank some more before it would actually start. It was all dialed in and tuned up, just a steaming pile of junk. All this with a full tank of gas, clean filters, topped up oil, etc. Never again.