...If you can not hear the fuel pump you will also not have ignition and you need to troubleshoot that problem first. ...

Ken Burton wrote on Wed, 31 August 2016 22:26

...If you can not hear the fuel pump you will also not have ignition and you need to troubleshoot that problem first. ...

Not so. The pump and shut off solenoid can seize up from the varnish in gas. Mine did. I had spark but the pump wasn't working when I first tried to get it running.

No matter what, take the shut off solenoid out of system and see if you hear the pump tick tick tick.

If no tick tick tick from the fuel pump, post here and I will tell you how to unstick it.

On Sep 1, 2016, at 8:31 AM, Mike wrote:

> If you prefer an original style board instead of the Dinosaur one, you can get them here:
> https://www.flightsystems.com/p-ONAN-300-1073-4950-B944.html

Good price but ugh, spade lug connectors. Notorious for being a point of failure especially when exposed to the elements and vibration.

--Jim

Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH




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Hi Everyone.

Just purchased a 1977 GMC Kingsley 26' Motorhome (Elvis) after many years of wanting one. I have enjoyed every minute of the experience so far. I know these machines are 40 years old now but nothing can beat the style and cool factor of a GMC! Recently I took it on it's innaugural run from Calgary, Alberta to Yakima, Washington and back with no problems. The one issue I am dealing with is the Onan generator. I had a friend look at it who does more modern generator repair and we think it might be the board?? I have also been watching the responses on the list about the Dinosaur replacement boards vs. the original boards. My generator cranks over fine but won't start. There is no spark at the plugs. I tried to follow the troubleshooting guide but that didn't seem to help. It sounds to me like the Dinosaur board is not that reliable. Is there someone in the network who can diagnose Onan boards and repair them. Locally the Onan/Cummins dealer is willing to sell me a new one for $1,150 CDN or a local RV shop can get me a Dino board for $363 CDN or I can source one out of the USA for $150-175 USD next time I go to Florida. I wouldn't mind sending my Onan board away to be diagnosed, but who can I trust to do that??

Still can't get enough of Elvis!!

Neil Roach

1977 Kingsley 26' (Elvis)
Mostly Original - 403 Engine
Steers like herding a group of cats down the road...

I think you missed the point. He already states that he has no spark. If he also has no fuel pump them he probably has no 12 volts to both as they are wired together. Yes he could have a double failure (pump and ignition) but we will address that when the time comes. We are not shooting a fuel pump problem at this time. He was shooting what he thinks is a board problem. We are trying to determine if the board is good or bad.

Ken Burton wrote on Thu, 01 September 2016 04:35

I think you missed the point. He already states that he has no spark. If he also has no fuel pump them he probably has no 12 volts to both as they are wired together. Yes he could have a double failure (pump and ignition) but we will address that when the time comes. We are not shooting a fuel pump problem at this time. He was shooting what he thinks is a board problem. We are trying to determine if the board is good or bad.

Not necessarily no spark. You can't see the spark in daylight.

He also said he tried to follow the troubleshooting steps. If he was actually able to do that, it would be running now.

My sister the mechanic took out a spark plug on mine and we cranked on the starter with pin 5 jumpered to pin 9. She said she didn't see any spark. But when I bought the thing, Kerry Pinkerton had told me he messed with it until he got spark, but didn't do anything to get it running after that. I trusted what Kerry said and told her to put the spark plug back in and prime the carb. With some gas in the carb, it sputtered. We gravity fed the carb and it ran and powered the roof AC.

The fuel pump didn't make a sound. It was seized with varnish from old gas. Once I got it freed up and got the shut off solenoid out of the picture (and ran a new line from the pump to the carb), we dropped one end of a fuel line in a gas can and the other end to the pump and ran the Onan again for 10 - 15 minutes.

Yes, there is no spark if the 5A fuse is blown. But I say again, just because you can't SEE any spark at a plug when it is pulled out, and you can't hear the fuel pump with a good fuse and 5 jumpered to 9, DOES NOT MEAN THERE IS NO SPARK. The spark is too faint to see in daylight, and the pump might be seized.

Once you get 12V to pin 9, and some air/fuel mix of some kind in the combustion chamber, if it doesn't sputter, THEN you can probably figure no spark.

And if that's the case, my first reaction is the points need to be rendered operable (IMHO, coils last longer than points). Once the points are working Then MAYBE a new coil.

I guess I am trying to say that (again, IMHO) when one has been sitting, the problem is MUCH MORE LIKELY to be FUEL related than SPARK related. The state of the ignition system is what it was last time it stopped turning. NOT SO WITH THE FUEL SYSTEM. Think about getting a lawnmower resurrected in the spring. If it was running when it was shut down last in the fall, the ignition system is still working.

I am NOT saying it has spark. I AM saying that the dim spark of this wasted spark system can fool you into THINKING it has no spark.

Save a bunch of fiddling and get some fuel/air mix in the combustion chamber (starting fluid) with 12V at pin 9 and with the starter spinning it. If it doesn't sputter, then fiddle with spark stuff.

And when it does sputter, if you can't hear the fuel pump, the pump will need to be freed up or replaced. And the carb might need to be cleaned/rebuilt. No matter what, get the fuel shut off solenoid out of the system.