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efstewart · 03-08-2015, 11:35 AM

I have a 2006 DSDP, model 3817, with a Onan quiet series 7500 generator that runs off of Diesel. I was using it almost daily for several months and did not have a problem. One day it just did not start.

Here is what I have done to it so far

Changed the oil, air, and fuel filters,

Checked the inline fuses inside the top cover of the generator.

It has 688 hours on it and I have been getting it serviced either by a good garage, or by myself ( I did the last service)

Any ideas before I take it to a garage?

GaryKD · 03-08-2015, 11:42 AM

Hi efstewart,
Does it crank but not start? Does is to anything to indicate it would like to start. Does the pre-heat light come on when trying to start it (the light on the dash switch)?

efstewart · 03-08-2015, 12:15 PM

Yes, the light comes on and it does preheat and it also cranks. It doesn't seem like it is close to starting when I crank it. I also pressed the stop button in order to prime the new fuel filter, according to instructions, and it still did not start. When I prime the filter should I smell some fuel, like with a car engine?

OldToolmaker · 03-08-2015, 12:30 PM

If most everything is working o-kay you should, at the very least while cranking, smell raw diesel fuel coming out the exhaust. At best you will have white finely atomized diesel fuel wafting away to annoy all and sundry. If this is where you're at then you ain't got no glow plug action going on. If you ain't there then you got no fuel and part of the injection system is airbound. So which is it? FWIW how cold is it where you are?

efstewart · 03-08-2015, 12:36 PM

So california, nice and warm today, so either I have a problem with no fuel coming into the new filter (I have a pretty full tank of gas), or I need to replace the glow plug?

GaryKD · 03-08-2015, 12:51 PM

Hi efstewart,
I agree, there is no fuel or no glow. Consider checking the new fuel filter first. It will be easy to determine if there is fuel to the new filter. If that is okay, the glow plug(s) may be a bit more difficult. The Onan Service Manual is attached to this post.

OldToolmaker · 03-08-2015, 12:54 PM

At the very least check that there is voltage at the glow plug, them maybe check if power can go through the glow plug. Ahhhhhh! You said you changed the fuel filter! What did you do to release the trapped air? You may need to crack the high pressure fittings to allow the air to escape. So crank and sniff then go on from there.

efstewart · 03-08-2015, 01:04 PM

Ok, I will try that later. Do I need to crack open both fuel lines or just one of them?

palehorse89 · 03-08-2015, 01:08 PM

Quote:

Originally Posted by efstewart

Ok, I will try that later. Do I need to crack open both fuel lines or just one of them?

No need to crack/bleed the fuel lines, these are self priming with a empty new filter, air is forced back to the tank.......
Try the stop/prime button several more times.......and see if that helps.
By your post in #3, a bit of air might still be in the system?........sounds like you are just about there by what you posted.

OldToolmaker · 03-08-2015, 01:10 PM

I'm a big believer in making space for good luck to occur. Do them one at a time, don't forget a rag and keep your body parts away from the spray if any. At those pressures the fuel will spray right through your skin but what you'll probably see is a little dribble of fuel and maybe some air bubbles. Don't forget to turn on the fuel valve.

Sky_Boss · 03-08-2015, 01:10 PM

I ran into a similar situation occur about 3 weeks after having the 1000 hour service done. I was getting ready to depart "home base" after sitting for those 3 weeks and while running all systems to verify we were ready to depart I discovered the problem. BTW...the generator had been tested and run after the service because I installed an AGS and ran several tests.

The symptoms were that I could crank the generator, hear it ALMOST start but it wouldn't run. I don't recall whether or not I could smell any fumes.

It turned out to be a bad governor signal wire wire connection. The shop that did the 1000 hour service fixed it for free. BTW...they slammed me into the shop on NO NOTICE other than a call that late morning on a Friday. They double checked fuel flow, scratched their head and almost gave up when the tech had the ah-ha moment. It was the first time he had ever run into that. According to him, this was not something that would have been disturbed or affected by the 1000 hour service but since I had just spend SOOOO much money...free was a curtesy for my continued business.

dennis45 · 03-08-2015, 02:04 PM

I had similar issues with mine last summer. Just for the heck of it, one day I pulled it out and disconnected the umbilical cord, sprayed both sides of the plug with electrical contact cleaner and applied a little dab of dielectric grease. Reassembled and have not had a problem since. Takes 5 minutes, give it a try.