Genset solenoid issue.

[Simi 60]

Have had an ongoing fuel solenoid or battery issue on a Kubota genset.
Because I rarely use it due a large solar array it has been down on my priority list to fix as I had a workaround.

I thought for ages that it was battery related, plenty of cranking power but not enough to click the solenoid in.
Workaround was battery charger on until battery showed about 13.5v and then the solenoid would work.
If needing glow plug as well I needed about 14.7 volt to get preheat, solenoid and start.
I thought the battery was failing under load.

Today I was going to replace the battery but before I did I connected up one of the big truck batteries from the main engine and........it wasn't the battery.

Next I checked voltage at solenoid and it was getting 12.47v and I could hear a faint click but not the loud click indicating it had sucked the plunger in.

Cleaned connections, no change so solenoid issue I think, unless someone has another idea?

Its a 2 wire solenoid being used
Almost all the ones i find online are 3 wire solenoids
What does the 3rd wire do and can I use one of these?

Thanks in advance.

[Jd1]

Three wire solenoids have (often) a 'draw' (not sure on terminology) solenoid and a 'hold' solenoid. The 'draw' solenoid uses a higher current to draw the solenoid into an active state but once active it requires much less current to hold the solenoid in that condition so the draw solenoid is deactivated and only the hold solenoid is kept active.
If the draw solenoid remains stuck in the on condition for too long it can burn out.
The switchover of draw to hold can also happen internally so you could have a solenoid that has the hold section working and the draw section burnt out and therefore not generating enough magnetic pull to activate the solenoid.
You could have too much friction someplace to allow activating the solenoid.
In order to use a 3 wire solenoid you would have to have external switching of some kind to control the power.
It doesn't make sense to me to have a 3 wire solenoid only for fuel unless it also does something mechanical or is a very heavy duty device.

[Bill Seal]

Beat me to it.

[Simi 60]

Originally Posted by Jd1

.
You could have too much friction someplace to allow activating the solenoid.
.

That 12v won't do it but 13.5v will?
Sounds like I pull it out tomorrow , take the boot off and see if a clean and lube yields results.

[OldGreyB]

Simi,
Jd1 is correct with regards to your question. But before you go off hunting for a replacement 2 wire solenoid, check your existing one is actually the issue. You don’t state what model Kubota engine you have on the generator, but online most of the replacement fuel solenoids are plungers that operate on the rack. Suggest you remove from the rack and energise, while having the admiral holding the plunger with a pair of pliers. Then you can see if the piston on the solenoid is moving or not and has “pull” .

Remember that grounding (or lack there of) is often the cause of electrical components not working as per design. So even with correct apparent voltage reading on your voltmeter, the lack of a good ground can cause insufficient current flow to allow the device to operate correctly.

Hence just using two wires from a known good battery directly to the solenoid terminals and doing the above test will give you an idea if you have 1) Bad wiring to the solenoid, 2) Faulty solenoid, 3) Fuel rack issue.

As an aside, I have seen your musing on the Trawler forum and hope to one day to meet you out on Morton Bay.

[Simi 60]

Its a Kubota d950 - Diecon engineering built 7kva.

[Simi 60]

UPDATE

Pulled solenoid out and hooked up wires and connected to same battery we use to start and it clunks in and out convincingly.
Pull the plunger out, squeaky clean and put it back together.
Still works but then I put the very slightest amount of hold on the plunger and its a no go.
Can't even feel it trying to pull.

New solenoid or does the bakelite end cap come off and could there be some crud in there affecting contact?

Its this one here
https://m.ebay.com.au/itm/Fuel-Shutd...a808%7Ciid%3A1

[Simi 60]

Update 2

Checked ohms plunger in and out and seems to meet spec (I found a solenoid troubleshooting guide online)

Checked again on battery, plunger in and out
Checked on engine wires and it tries, but can't do it.
Connected clean wire to ground and it tries, but can't do it.
Connected clean wire to positive and to first set of connections and it tries, but can't do it.
It still sees 12.4v on multimeter. )-:

Seems its a problem with that wire between switch panel (solenoid button) and the first connector.
Investigating further.

[Simi 60]

Update 3

Traced wire back to switch panel , disconnected at genset and and piggybacked a new one into the solenoid button at panel.
Went below and it tries, but can't do it.

Rude words said, gave it a stern talking to and I need the genset for 30 minute kick start to the day so connect everything back up as it was, put charger on to bring it up to 14+v like previous start procedure, walks up stairs and sees 12.7v at the panel and thinks, I wonder...............

7 seconds of glow plug and presses the button, hears click and turns key and the bastard starts.

Obviously it was the rude words and stern talking to that fixed it.

[Jd1]

Originally Posted by Simi 60

Update 3

Obviously it was the rude words and stern talking to that fixed it.

Glad you got it solved! I find that hitting things works really good too - whatever caused the issue is afraid and starts to cooperate!

[OldGreyB]

Originally Posted by Simi 60

Update 3

Obviously it was the rude words and stern talking to that fixed it.

Glad to read you are generating. Just shows what a stern talking to an inanimate object does!

If it plays up again, PM me as I have a few other suggestions if the stern talking to does not work again.