Author Topic: Generator voltage drops  (Read 853 times)

Jackie

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Re: Generator voltage drops
« Reply #15 on: January 02, 2019, 02:52:30 PM »
Hi,
Thx for info The fuel rack is exactly like mine I will get some fuel system cleaner but I do not have any rust or anything dirty in this rack area but yes inside might be dirty
Let me check it out!!
Jackie

dieselspanner

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Re: Generator voltage drops
« Reply #16 on: January 02, 2019, 05:25:42 PM »
As it looks like a governor problem you could try........

Disconnect everything except the water pump, start the genny and then use a bit of string, baling wire or bootlace to manually get the revs into the correct zone and stay there.

As it's a constant load it should stay wherever you leave it, with a bit of luck whatever is stuck could well free up with the warmth and vibration, should you be that lucky the motor shouldn't overspeed, the governor ought to shut it down.

Anyway, if you stand by it for half an hour or so you'll have moved some water in the right direction whilst Bob continues with the non bush engineering side of the problem!!

Cheers
Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

dax021

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Re: Generator voltage drops
« Reply #17 on: January 02, 2019, 05:29:04 PM »
Jackie, where in SA are you?

Jackie

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Re: Generator voltage drops
« Reply #18 on: January 02, 2019, 05:35:37 PM »
Hi
I live in East Londen

Jackie

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Re: Generator voltage drops
« Reply #19 on: January 03, 2019, 08:57:37 AM »
Hi Bob
How is your time to further test / check the engine governor side please?

dax021

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Re: Generator voltage drops
« Reply #20 on: January 03, 2019, 01:07:50 PM »
Jackie, you are lucky.  EdDee on this forum is a genius and he lives in EL.  I'm sure he can help you if he pops his head up.
« Last Edit: January 03, 2019, 01:11:34 PM by dax021 »

Jackie

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Re: Generator voltage drops
« Reply #21 on: January 03, 2019, 04:18:46 PM »
Hi Dax021,
I am hoping that Ed Dee is back on the seventh Jan as he was very willing to assist me
Will keep you guys posted on the outcome!!

ajaffa1

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Re: Generator voltage drops
« Reply #22 on: January 03, 2019, 11:09:53 PM »
Hi Jackie, I did send you a dropbox link where you should be able to download the workshop manual. Since I have very little faith in modern technology, I also printed and scanned the relevant pages and have emailed them to you. I also attach a couple of photos of of the governor assembly on mine before I rebuilt it.

When you get my email, please see the top left hand corner of page 39, it is very possible that you have this speed adjustment on your engine. If the spring is damaged it might well bog down under load.

If EdDee lives locally he would be an ideal man to help resolve these issues.

Bob

Jackie

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Re: Generator voltage drops
« Reply #23 on: January 05, 2019, 12:59:23 PM »
Hi Bob
Just opened mycover and governor looks identical to yours Does this gorvenor work on your genset I will look at that spring on P38 that you are referring to aswell If i do not come right I will contact ed on Monday to assist
Thx so long

ajaffa1

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Re: Generator voltage drops
« Reply #24 on: January 05, 2019, 09:43:45 PM »
Hi Jackie, yes that type of governor works very well on my generator and holds RPM to within 1/2 a percent, even under heavy load. My generator is a Startomatic so it has a solenoid to switch the fuel rack on and off. It also has the adjustable throttle mechanism shown in the photo. the RPM can be adjusted by loosening and tightening the long bolts.

Bob

Jackie

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Re: Generator voltage drops
« Reply #25 on: March 30, 2019, 06:16:58 AM »
Hi guys
Good news I found the fault on my lister st 2 8kva genset wrt volt drop under load In the control box there is a rectifier snd current tranformer The transf was fine but somehow previous owner swapped the bridge rect positive and negative The genset is now running inductive loads starting on 15 amps with minimall change in voltage and freq I just changed the bridge frectifier for good measure So all the stripping governors and injector checks are now done anyway but at the end a R40 bridge caused the fault
Thx to all for help much appreciated

ajaffa1

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Re: Generator voltage drops
« Reply #26 on: March 30, 2019, 08:33:23 AM »
Well done Jackie, you managed to resolve a very unusual problem. I hope your Lister will now give you many years useful of service.

Bob

glort

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Re: Generator voltage drops
« Reply #27 on: March 30, 2019, 10:45:21 AM »

Sounds a bit like 3 problems I have come across in the last couple of weeks with petrol engines.
Everything pointed to the carbs but turned out to be Ignition.
Had me fooled till the 3rd one.

1st one a mate couldn't get the engine on his cherry picker to run properly.  Pulled the carb, seemed ok, cleaned it and put it back, same. Changed carbs from another similar running engine. No difference.  He'd put new fuel in it that morning thinking the thing had got water or condensation in it.  Mate casually mentioned it was running fine till they changed the starter motor. I said that should change anything. Son said what a pain it was having to remove the Flywheel and coil .

I said what did you gap the coil at when you put it back on?  About 2-3 mm?  DOH! Thereeers  "ya problem!!

Off comes cover, yep, waaay too wide. What should it be? Buggered if I know mate but closer than that! I'll gap it by hope and inspiration and see how it goes.  Thing fired on the first compression stroke and ran like it should. Mate didn't know whether to hug me or smack his son in the back of the head.
they had been frigging with it 2 hours before I showed up.

2nd one was my over size weed wacker.
Ball tearer of a machine that is over powered substantially ( 75cc 2 stroke) but I was tearing my hair out trying to get it started and keep it running.  Again pulled carb apart, several times, re tuned and did everything I could think of. Exhausted from yanking on the thing I held it different and got a belt off the plug wire. HUH???

Turned out the HT lead had pulled back in the rubber cap and the spark was having to jump to the plug.  Pushed it back and re connected it onto the plug and like all my 2 strokes, only have to will the thing to start now hot or cold and it does.  Must have been not connected right when I got the thing because it NEVER started so easy before and the thing has scary power now. Can rip though any woody weeds with teh thickest line they make and never need more than 30% throttle.

3rd one was neighbors Mower.
Ran the thing out of fuel and I heard it backfire. He refilled it and when he got it to start the thing would barely rev and when it did the exhaust was glowing in about 30 sec.  He was fiddling with the carb and changing the fuel filter and when I heard the cursing and blue words  after he fired it and it was coughing  again, I went over to see how I could  make the situation worse.
The exhaust was shooting flames better than a top fueler which gave me the clue.

I pulled the plug, held it on the head  while he cranked and the timing was so far out I could feel and see it was off by the pressure out the plug hole. Ah Hah! I know what happened here!

Took off the blower cover and could see the Flywheel had sheered the key in the crankshaft and had rotated quite a bit making the timing very late.
He went into town, got another couple of keys, I lapped the flywheel for him and we put in the new key , put the flywheel back on and again it went first touch of the key although the mixture was now rich as buggery so had to re set that again. 

Geez these petrol things are misleading and complicated!! 

 :laugh:

dax021

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Re: Generator voltage drops
« Reply #28 on: March 30, 2019, 01:21:22 PM »
Jackie, would you mind posting some photo's of the inside of your junction box.  My Hoffberg generates fine, but the battery charger is putting out something like 60V.  I'd like to compare, thanks.

ajaffa1

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Re: Generator voltage drops
« Reply #29 on: March 31, 2019, 10:06:36 AM »
Hi Glort, I have seen the ignition coil gap problem so many times it always one of my first checks. Without a good spark it`s never going to light off. A trick I learned years ago and have used ever since is to put a strip of insulating tape on the flywheel. Adjust the coil until it touches the tape and tighten, spin the flywheel and remove the tape. Insulation tape is around 10 thou thick, I have never had it fail. It`s a lot easier than buggering about with feeler gauges, even if you know what the correct gap is supposed to be.

Bob