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Ronbstewart · 05-27-2014, 02:24 PM

I currently own 94 Monaco Executive with 7.5 Kubota/Kohler generator set. Unit had about 1100 hrs when I purchased it. Dealer knocked off $500 dollars because generator would start every time and run as long as start button was pressed and quit when it was released. Turns out to have been bad/worn brushes in the DC section. $60 for the brushes and a couple hundred to have them put in, it has run great every since. It has just over 2600hrs now. Had to replace radiator cap once but no leaks or drips anyplace. What has always bugged me is the noise. There's not a problem with anything that needs to be fixed or tightened up such as valves or exhaust system. I took it to a dealer who states it's a great generator back then they were just a bit noisy. So I know the general thought is I should just sit down, shut up and be happy. But I'm not. My beast of choice is a good used Onan 7500 Quit Diesel. I'm hoping to find one in and around the 3 to 4 grand mark. But I've heard some horror stories about the rotors spitting out magnets in thousand hours or less. I would like to hear your yea's and nay's on this unit and what models or model years to stay away from. At 74 I still work a 40 hr week in the office, still get to travel some, but calling it quits next year and plan to travel a lot.

1skier · 05-27-2014, 03:49 PM

Not sure about the Onan 7.5 KW, but I really like my 2007 Onan 8 KW. 1100 hours or so and all I have ever done to it is regular maintenance and run it monthly. Ultra reliable and quiet to boot!

Dr4Film · 05-27-2014, 04:04 PM

HERE is a good place to find reasonably priced used Onan QD generators.

I own the Onan QD-7500 with almost 600 hours. I also belong to the Monacoers group which has well over 4000 members and I can tell you with confidence that the situation you described is rare. In fact I cannot remember if any member has had a failure of that nature.

Dr4Film ----- Richard

HicksRA · 05-27-2014, 06:56 PM

Whoever said "Nothing runs like a Deere" never owned an Onan.......

Ray,IN · 05-27-2014, 10:05 PM

An old post here has the fuel consumption rates for almost all MH gensets. The Onan 8K uses less fuel than the 7.5 according to the chart in that thread. Something about the variable-speed genset.

94-Newmar · 05-28-2014, 05:24 AM

Ron, my coach has a 94 Onan 7.5 DKD series genset. A bit noisier, but by no means offensively louder than the newer QuietDiesel series. Units of this vintage didn't have whole-unit shrouds around them, but nonetheless it's an absolute workhorse. Your Kohler unit is of the same quality and reliability. Should this DKD series parts ever become extinct I will, without hesitation, replace it with a 7.5 HDK series QuietDiesel Spec D or above. The rotor issues were from an earlier Spec unit and always failed in the first 1-200 hours and Onan extended their warranty to cover those units. That is no longer, nor will be a problem in the future. There were relatively few of those units produced before they caught the issue.

You could always construct a shroud for your unit, I have considered doing so on mine as well. I have seen others whom have done so. Care must be given to ensure airflow continues from the intake side of the radiator across the engine and exits properly. I've never taken the time to start this project as mine just simply isn't loud enough, and have certainly never had any complaints from anybody.

JManatee · 05-28-2014, 06:51 PM

Can you describe the noise? Have you listened to a new one for comparison?

Just because it is diesel doesn't make it supper quiet

Fred Cooper · 05-28-2014, 07:08 PM

Quote:

Originally Posted by 94-Newmar

...text deleted.... The rotor issues were from an earlier Spec unit and always failed in the first 1-200 hours and Onan extended their warranty to cover those units. That is no longer, nor will be a problem in the future. There were relatively few of those units produced before they caught the issue....text deleted

From what I've read, the problem rotor's were about 1999-2001, and I experienced this failure. Onan extended the warranty to the ORIGINAL OWNERS ONLY, and cleaned out my bank account to the tune of $4200.

I've also read where some owners were able to change the failed rotor's themselves saving lost of dollars.

Fred

Ronbstewart · 05-30-2014, 02:52 PM

Thanks for all the replies, JManatee asked about noise type, it's nothing out of the normal for an unenclosed unit. It's more me being jealous of my friends whose units are so quiet you almost don't realize they are running when setting inside the coach, mine seems to only be like that when I'm in the bed room. Have run across a Onan Quiet Diesel 7.5 model 5HDKAJ11451H that I can get for $3000 to $3500 hours are sort of high (about 6500) owner upgraded to a Onan 12000, it was on a 22' trailer toter pulling a 40' trailer pulling race cars, he needed a Gen that could power about 4 AC and other stuff. The 7.5 was installed by Onan and all service and repairs was done by them. Owner says it was always well maintained and serviced as in the racing business everything needed to work properly all the time. Anyone have experience with this model?