803a vibration

smokem joe · Apr 14, 2018

I went through a unit today that I picked up at auction a couple months ago. It is an 2010 803a with only 10 hours on it. Paperwork inside shows it was a national guard unit so it was never ran. Only repairs shown were battery charging and repair to one door they dented up so it wouldn't latch. Unit is spotless so I believe the hour meter in this case. Paperwork has correct serial number on it and hours match repairs listed.

It came from GL, and the odd thing was other than batteries it was complete. All fluids were in it, all filters were intact, and half a tank of fuel. The water separator was a Carquest filter so that was not original. Unit fired right up after changing fluids and filters. It made some odd noises that settled down to normal after running a few minutes. Engine sounds completely normal now after 20 minute run with no load.

It seems to vibrate a little more than a normal 803 though. Any thoughts as to what would cause a little more vibration than is common on these?

uniquify · Apr 14, 2018

Do you have the generator on the ground, floor, or some other firm surface? Or is it on a trailer or some sort of dolly? I had a 802 bounce like crazy on a dolly I made of 2x6's with a caster at each corner, but it ran pretty smooth once I put it on the ground. They also seem to do well on a trailer. I think the trailer's tires and suspension helps.

Another thought... I wonder if one cylinder is getting more/less fuel than the others. Do you have access to an IR thermometer? If so, check the temperature each cylinder. A large discrepancy may indicate that you need to adjust one of the fuel lift/meter pumps.

jamawieb · Apr 14, 2018

Have you put a load on it yet? You could have an injector not firing correctly causing the vibration. Usually it won't hold a 10kw load with a bad injector.
Also, could be the mounts. I believe the mounts for the 802a are little softer and if someone mismatched the mounts, it would cause more vibration. I.E put 802a mounts in for the 803a.

Guyfang · Apr 15, 2018

Roger that. The 802 mounts are made of a softer material. And that often happens.

Another thing you can try, is to start the set up, then loosen the IP's, one at a time, and turn then a tad back and forth, and see if the set runs a little smoother. You can put a wrench on them, and then make fine adjustments. I had several sets that ran rough, and this helped smooth them out.

Also check the mounts. Make sure they are tight, that all parts are there, (the big washers are often missing) and not cracked. Dosnt hurt to smear them with silicone grease, to keep them from cracking.

smokem joe · Apr 15, 2018

Thanks everyone. I will not have a chance to work on it for a bit but will keep you updated. I do have a thermometer to set injection pumps. I have only had to adjust one unit so far. I'll check temp on exhaust manifold and try that first. I have not put any sort of load on it yet. I ran it for 20 minutes just to get it running since records showed it hadn't been run since 2013, and that was only to charge the batteries and run it. I doubt this unit has ever been under much of a load in it's 10 hours. Anyone have a point of reference as to manifold temps for setting pumps? The center will be hotter for sure. How many degrees hotter than the ends?

I did check all the motor mounts first thing after seeing it had a vibration. They looked correct as they had the same amount of squish as the other dozen I have worked on. They look brand new, no cracks and all parts are there.

I work on these sitting on a 12x12 wood block under each corner. That picks it up enough to make it easier on my back. I've started several on this exact setup with minimal vibration so I don't think it is the way I have it set up.

I've only had one 802 that I've worked on and it vibrated for sure, but this particular 803 has more than the 802!

jamawieb · Apr 15, 2018

I take the temperatures on the head, right below where it attaches to the exhaust manifold. You'll have 4 flat portions of the head, it's about even with the oil pressure sending unit. Temperatures usually are 190-198 with no load and there will be about 1-2 degrees difference.

smokem joe · Apr 15, 2018

jamawieb said:
I take the temperatures on the head, right below where it attaches to the exhaust manifold. You'll have 4 flat portions of the head, it's about even with the oil pressure sending unit. Temperatures usually are 190-198 with no load and there will be about 1-2 degrees difference.

Ok that helps. Taking the temps from there do you notice a big difference if a pump isn't set right?

jamawieb · Apr 15, 2018

Yes, if an injector is not working correctly you'll see a swing of more than 8 degrees plus or minus. They could be all out of wack so take some temperature readings and report back.

smokem joe · Apr 16, 2018

Will do! It could be a couple weeks before I can work on it again.

smokem joe · Apr 26, 2018

Ok I had some time this morning to work on the unit. I let it warm up and checked temps on head. It was only 45 degrees here so my temps were 184-186. I had the cylinder close to the fan down about 5 degrees. I turned the pump clockwise a little and the temps all seem to be pretty even. It pulls 11K watts with no problem. Still has more vibration than normal. It got a little smoother as it ran, but not like any of the other dozen I've worked on.

Problem came up when I closed the breaker to apply load. I saw a flash out of the corner of my eye, and now voltage gauge only shows 120v when on the 240v setting. Black spot appeared on gauge face also. Unit still puts out correct voltage. I have 240v and running 11k load. But gauge is only showing 120. Seems like I had to adjust voltage up higher than I had it before as well to get to 120v.

Motor seems pretty smooth but makes a weird sound. Hopefully it comes through on one of the videos. Governor has been messed with for sure and is set way different than any I've seen. It does pull the load, and I don't normally do this but I did dump 11K on it all at once to test it. HZ dropped to 58.8 and then recovered to 60. Motor mounts are all intact with all pieces and don't seem to be compressed any more than normal.

Any ideas on voltage gauge and vibration/sound?

smokem joe · Apr 26, 2018

View attachment 074.MOV

smokem joe · Apr 26, 2018

Ok I guess I'm not clear on how to attach a video! It does work if you open it though

Guyfang · Apr 26, 2018

smokem joe said:
View attachment 726464

In the second picture, you can see where someone has knob dicked the governor. I don't know if you have read the adjustment procedure for the governor, but a short version is in the SS form for Technical manuals. Go to the 803 thread, and the last document, bottom, is the procedure. I would try and readjust it properly, by the procedure, then see if that helps.

Guyfang · Apr 26, 2018

smokem joe said:
Ok I had some time this morning to work on the unit. I let it warm up and checked temps on head. It was only 45 degrees here so my temps were 184-186. I had the cylinder close to the fan down about 5 degrees. I turned the pump clockwise a little and the temps all seem to be pretty even. It pulls 11K watts with no problem. Still has more vibration than normal. It got a little smoother as it ran, but not like any of the other dozen I've worked on.

Problem came up when I closed the breaker to apply load. I saw a flash out of the corner of my eye, and now voltage gauge only shows 120v when on the 240v setting. Black spot appeared on gauge face also. Unit still puts out correct voltage. I have 240v and running 11k load. But gauge is only showing 120. Seems like I had to adjust voltage up higher than I had it before as well to get to 120v.

Motor seems pretty smooth but makes a weird sound. Hopefully it comes through on one of the videos. Governor has been messed with for sure and is set way different than any I've seen. It does pull the load, and I don't normally do this but I did dump 11K on it all at once to test it. HZ dropped to 58.8 and then recovered to 60. Motor mounts are all intact with all pieces and don't seem to be compressed any more than normal.

Any ideas on voltage gauge and vibration/sound?View attachment 726460 View attachment 726461

From where did you see the flash?

jamawieb · Apr 26, 2018

Something arched inside the gauge so you will need a new gauge. The vibration could be the rotor. I think, I've read that you could pull the rotor and turn it 180 degrees to help with vibration problems. But that could have been on something else I was working on.

smokem joe · Apr 26, 2018

Guyfang said:
In the second picture, you can see where someone has knob dicked the governor. I don't know if you have read the adjustment procedure for the governor, but a short version is in the SS form for Technical manuals. Go to the 803 thread, and the last document, bottom, is the procedure. I would try and readjust it properly, by the procedure, then see if that helps.

I was looking that up at the shop this afternoon but ran out of time to actually do anything with it. I can't figure out why someone monkeyed with it so badly, and how it runs in spec with it being so far off.

smokem joe · Apr 26, 2018

Guyfang said:
From where did you see the flash?

Just saw it out of the corner of my eye. I was watching load as I flipped breaker to load the unit. I think it was from the gauge but not 100% sure. I had it running with just a halogen light on it a week and a half ago and it worked fine then.

smokem joe · Apr 26, 2018

jamawieb said:
Something arched inside the gauge so you will need a new gauge. The vibration could be the rotor. I think, I've read that you could pull the rotor and turn it 180 degrees to help with vibration problems. But that could have been on something else I was working on.

I have one extra gauge on a parts unit. I don't want to install it and fry it as well though. Freak thing? Chance of frying a new one? I could see if something arced inside and killed it completely. Is there something inside that would let go and show half voltage? I guess I will be tearing that one apart to inspect and see what happened.

Vibration is less with 11K load on it than with no load. But it is enough that the Hz changes, even with the lock tightened as much as I can. It moved 1.5 to 2 Hz on its own.

Guyfang · Apr 27, 2018

Did the needle on the gauge go back down when you shut the set off? Or stay in the middle,(approx 120 volt range) after shutting off? What says your multi meter when you use it on the back of your meter? Like jamaweib said, its probably the meter. The meter takes its signal direct from the S6. The S6 directly from the S8. So unless you have some sort of major malfunction on the two switches, it can only be the gauge.

And yes, even though its a PITA, I would at least loosen the rotor mounting bolts, spin the rotor, and put it back together. Or completely remove and spin it 180 degrees. Normally loosening it and spinning it works.

Bmxenbrett · Apr 27, 2018

Since that gauge is basicly junk theres no harm in taking it appart. I would guess that a 120v wire came loose and shorted to the case..thats why it still shows 120v.

803a vibration

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