Onan 20 KW generator won't start - Has to be electrical

ragin cajun said:

Glad you found the problem! Could it have been a faulty reset switch?

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Uh...no...re read my last sentence.

twistedtree said:

So much for the mechanic who took patr of the injection pump home for repair.

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It's even worse than that....turns out the "repair" was installing a new O ring on a part on the injector pump easily removed from the outside !

1 insane not to have a general O ring selection kit on the truck in the first place

2. And if not , just drive to the hardware store 3 miles away and come back within 30 minutes.

3. With the icing on the cake being that had absolutely nothing to do with the actual problem in the first place.

I'll tell you more when at a regular keypad...don't like typing on a virtual keyboard.

I'm guessing the problem was a cable that got knocked loose, probably by someone who you paid to fix something else.

I'm guessing if he would have listened to me the genny would have been running 32 posts ago. :lol:

Dune said:

Fixed it. Now you guys get to guess what it was

Hint- it was electrical to panel related and ridiculously simple....but not a blown fuse and not a tripped or defective sensor fault breaker.

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I wait with abated breath.

what_barnacles said:

I'm guessing if he would have listened to me the genny would have been running 32 posts ago. :lol:

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Perhaps if you had been more detailed in that part of your response you might have a point, but obviously there was "power to the generator" as the starter was turning it over just fine. And how to determine if there was power to the gauge panel was both unclear (before I got the service manual) and difficult due to having to remove the water maker obstacles before I could even get a decent look in there.

But really, I know now, the first thing to check with symptoms like this, during cranking, is if there is power to the injection pump solenoid, which in spite of my bizarre mechanics proclamation, there was not.

Anyhow, the answer is I did remove the water maker stuff (my lord why do these things need a dozen hoses and so lame they use nuts and bolts instead of bolts in proper tapped holes ??) in the way and got the top panel off finally. Only then did I see that someone in the past had apparently redone the DC main power supply wire to the panel and their crimp fitting had failed...just a few wire strands still hanging on. So, re did that with new fitting and all was well.

Thanks for the suggestions..esp Ski in NC and Alaskan for the phone number to Cummins/Onan...which was extremely helpful to have proper manuals !

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Now, just out of curiosity.....if an injection pump solenoid ever goes bad can it be replaced with a new one or do you have to replace the entire injection pump ? And if so, any idea what a new injection pump would cost on a 4 cyl Cummins diesel ? (yes, I'm sitting down.... )

I replaced a stop solenoid on a 1979 Onan a few years ago and it cost $600!

I recently replaced one for my current boat's Onan but this time I bought a Chinese knock-off o E-bay for under $100.

A new pump could be a few boat units.

That's a Stanadyne pump. All parts should be available and serviceable at an injection shop. No need to go to Cummins.

Do note that this engine was mfr'd by Onan, then Cummins bought Onan. Tagged as a Cummins, but they never made any of the parts. It's production run was not very long and many engine parts are no longer available. Good reliable engine, but an orphan.

Ski in NC said:

That's a Stanadyne pump. All parts should be available and serviceable at an injection shop. No need to go to Cummins.

Do note that this engine was mfr'd by Onan, then Cummins bought Onan. Tagged as a Cummins, but they never made any of the parts. It's production run was not very long and many engine parts are no longer available. Good reliable engine, but an orphan.

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Right, Stanadyne pump...so is the bizarre secondary fuel filter (but Napa has them) Thanks Ski.

Glad you found your problem. Always look up the part number on Google first. I have bought a lot of parts from Jack's Small Engine at a good discount. The only issue is it could take a few weeks to get the parts.

twistedtree said:

I'm guessing the problem was a cable that got knocked loose, probably by someone who you paid to fix something else.

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On the offhand chance the end of your sentence was supposed to imply I often pay for mechanical or electrical boat related services, nothing could be further from the case. I only employed a mechanic this time as the boat is for sale, and part of the contract was that the generators be "certified" by an Onan repair facility !

I suspected it would be a complete waste of money from the get go, but nonetheless agreed just to get the contract thru. Only later I find out the mechanic was highly suspect in his knowledge base, especially on the electrical end of things. But at least the buyer got his "proof" the generators are in excellent condition.

As an aside, all I ever got was a credit card charge for $730.... no invoice explaining the hours, O ring costs, nothing. An email to the company about this received no response.

The mechanic spent less than 3 total hours on the boat. Travel time I would estimate at maximum 45 minutes x 4 (2 trips) but it should have been 45 x 2, since the second trip should have been completely unnecessary if he simply had the O ring with him, or went to the hardware store* just 2.5 miles away to fetch one.

Amazing, isn't it ?

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*This Tru Value hardware store has the motherlode selection of O rings, btw. I went there on Thursday for something else and while there asked to see what they had in O rings which confirmed what I suspected.

Dune said:

On the offhand chance the end of your sentence was supposed to imply I often pay for mechanical or electrical boat related services, nothing could be further from the case. I only employed a mechanic this time as the boat is for sale, and part of the contract was that the generators be "certified" by an Onan repair facility !

I suspected it would be a complete waste of money from the get go, but nonetheless agreed just to get the contract thru. Only later I find out the mechanic was highly suspect in his knowledge base, especially on the electrical end of things. But at least the buyer got his "proof" the generators are in excellent condition.

As an aside, all I ever got was a credit card charge for $730.... no invoice explaining the hours, O ring costs, nothing. An email to the company about this received no response.

The mechanic spent less than 3 total hours on the boat. Travel time I would estimate at maximum 45 minutes x 4 (2 trips) but it should have been 45 x 2, since the second trip should have been completely unnecessary if he simply had the O ring with him, or went to the hardware store* just 2.5 miles away to fetch one.

Amazing, isn't it ?

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*This Tru Value hardware store has the motherlode selection of O rings, btw. I went there on Thursday for something else and while there asked to see what they had in O rings which confirmed what I suspected.

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Our local Ace hardware has a large number of O-rings. And a good selection of SS nuts and bolts. But much better prices for nuts and bolts is at York Bolt.
York bolt is more than 50% cheaper than Ace hardware.

https://www.google.com/maps/uv?hl=e...ved=0ahUKEwivqJvz6uzTAhXIeSYKHSlWAWQQoioIdTAK

If these o rings are the ones at the top of the injector pump (common issue with Onan) I was told to use OEM rings. But they were $10 each.

sdowney717 said:

Our local Ace hardware has a large number of O-rings. And a good selection of SS nuts and bolts. But much better prices for nuts and bolts is at York Bolt.
York bolt is more than 50% cheaper than Ace hardware.

https://www.google.com/maps/uv?hl=e...ved=0ahUKEwivqJvz6uzTAhXIeSYKHSlWAWQQoioIdTAK

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Good to know but in this case I don't think I would have fretted too much about paying 39 cents for an O ring that would have saved hundreds of dollars vs another trip ! Plus it was needed immediately.

Alaskan Sea-Duction said:

If these o rings are the ones at the top of the injector pump (common issue with Onan) I was told to use OEM rings. But they were $10 each.

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Told by who ? If told by someone like my guy, it would be meaningless. But this one was on the left side, probably just for bleeding purposes as the steel fitting screwed in. There was a small leak there and it did need replacement but had absolutely nothing to do with my generator not starting.

As an aside, McMaster Carr sells O ring "kits" that are comprised of various O ring diameter strands and a special plastic holder that allow fitting in the strand of proper diameter and cutting a straight cut with razor blade. Then the ends are glued together with "crazy glue"....which amazingly, does hold rubber or butyl of that composion probably better than it holds anything. If you were to stretch an O ring glued together in that way until it broke it would probably break somewhere other than at the glue joint.

Of course it would still be better to have a purpose sized and diesel resistant O ring but in this case, for example it would have solved the leakage for weeks until the exact right O ring was obtained.

Hardware store o-rings are generally nitrile rubber and rated at 80 deg C. (176 deg F)

Some O rings are not compatible witg fuels. They may fit and seal for a while. Then you are back where you started.