Author Topic: Generators gone wild...  (Read 3699 times)

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Offline bj

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Generators gone wild...
« on: May 16, 2016, 07:04:44 am »
[MOD EDIT]
... insert 1/2 quart for the first 3 minutes, 1 quart per each additional minute...


Oops, cut this wrong... Split off from the scratch pad thread...

Quote from: madscientist267
The other notable issue is the generator is burning copious amounts of oil, and while I know it's probably both rings and the valve guide seal (apparently there's only 1, on the intake), the onset was quick enough that I think the seal is the primary culprit. Won't know until I get in there to look at it, but at least it looks like I may not have to remove it from the truck to inspect/repair it. If it's deeper than that, I'll just have to deal with the smoke and plug fouling as necessary until I can do something to replace the unit. It otherwise runs fine (but I can tell the plug is partially fouled already because it's stumbling above about 700W load or so... just need access to a bench vise to clean it (I'm not gonna drop a new plug in it every 10 hours, the oil is expensive enough!)


[/MOD EDIT]

  On the generator-----I have seen them do the oil thing suddenly because the crankcase
vent valve is stuck/plugged/just plain pooched.  Or, as you said could be rings or intake
seal.  Usually they don't come on suddenly though.
   If you can see in the spark plug hole with a good light, check the piston top.  Lots
of carbon on top, with edges clean about 1/4 in means rings.  Whole top carboned
means guide.
   Not all that easy to see there sometimes though.
"Even a blind squirrel will find an acorn once in a while"
bj

Offline MadScientist267

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Re: Generators gone wild...
« Reply #1 on: May 16, 2016, 07:13:13 am »
Sweet Bj, that's good experience talkin' there, I can just feel it ;)

I can see the crown pretty well thru the hole... I haven't had a real chance to look down in since it happened, but I did pull the PCV hose off the filter housing and it does indeed seem a little weak now that I think about it... I've always thought of that as a push-pull relationship but yeah you're right, it should be stronger even on it's own than it is. I'll figure out a way to hit it with some suction and see if I hear anything pop open and/or it makes a difference. While I'm there I'll pull the plug and look down in there and report back... it's gonna need to be cleaned up anyway.

Steve
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Offline MadScientist267

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Re: Generators gone wild...
« Reply #2 on: May 16, 2016, 03:09:21 pm »
Ok... got an updated report and a pic.

The pic is more useful than the report.

And it's not revealing any real secrets...

5658-0

We've seen this theme before, in the generator cleanup thread. I'm not gonna get all excited this time around, the novelty of it has worn off. :-\

The report:

The plug hole is much smaller than I remember it, and without a camera, I'm simply not going to see the edge of the crown and the wall in the same frame of reference... not for lack of trying... I even thought I was being clever by trying a laser pointer as the light source. Turns out, the white LED right next to it is still more suitable, but that's all for naught.

The crank simply doesn't have enough throw to get the piston out of the way far enough.

The PCV:

The "good" news - It's not completely blocked...

The bad news - My oral cavity isn't calibrated in mbar, atm, psi, kPa, or any other scale one might find air pressure and lack thereof listed in.

The "not-as-bad" news - I tried it but I didn't inhale

So I still basically don't have a whole lot to go on. I made sure to cycle the crank thru all 4 strokes and then some, a quarter turn or so at a time; no perceivable difference.

The only thing I can say for certain at this moment in time is that there's no gas in the crankcase, but it still tastes like $#!+.

I can't get to the PCV retainer bolts despite it being right there in front of my face... something about a plastic cooling duct and laws of physics, I can't recall exactly.

So, where does this possibly stand... From what I *could* work out, the carbon is highly irratic on the crown, but off to the one side I could see clearest, it *seems* like it may even be thicker near the wall? I really don't know what to make of it, and an eyeball I had "full usable 3D control" over was difficult enough to make sense out of anything... forget it with a once again temperamental phone camera.


This was taken the other day while I was up at the auto parts store and had replaced the majority of the [then missing] oil with the last combination that was known to be ok... which didn't work, and neither did adding "stabilizer goo".

The special fx are courtesy of good old fashioned frame rate slip. :)

Okie... ideas? LOL

Steve
Wanted: Schrödinger's cat, dead and alive.

Offline bj

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Re: Generators gone wild...
« Reply #3 on: May 17, 2016, 08:42:12 am »
  To state the obvious, that is a lot of oil consumption.
  From what you were able to see, probably the guide/seal are the worst of it,
but rings may not be wonderful either.
  If you don't have it back together yet, try a brisk pull on the cord with the plug
out.  The vent valve should make a sound somewhat like a goose honking on
every stroke.  (it is a reed valve)
  As always, wish you were closer for help.
"Even a blind squirrel will find an acorn once in a while"
bj

Offline MadScientist267

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Re: Generators gone wild...
« Reply #4 on: May 31, 2016, 12:42:22 am »
Bj -

There's a pretty decent chance that it's the PCV, and as of yet, no geese.

Also should have access to a suitable camera here in the not too distant future so the crown can tell a clearer story.

Right now, between this and the #4 battery, I'm running in critical load only mode most of the time, as the weather is also having it's way with us for the time being.

Hopefully I'll have more info about the generator in the next couple of weeks. The battery *should* at least be getting replaced in the morning... and after that the rest of my week is either filled completely out, stuffed with weather, or both. Maybe if I'm lucky (for a welcome change? LOL) I'll be able to look inside this weekend.

Steve
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Offline bj

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Re: Generators gone wild...
« Reply #5 on: May 31, 2016, 07:07:13 am »
  Haven't seen much of the sun here either.  UP side, had a fair bit of rain, which was much
needed.
   Hopefully a replacement battery, and a bit of sun, (fingers crossed) will get you out of
critical.
"Even a blind squirrel will find an acorn once in a while"
bj

Offline DBCollen

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Re: Generators gone wild...
« Reply #6 on: May 31, 2016, 10:05:32 am »
an old farmers trick for glazed cylinders is to "puff" some bon-ami  scouring powder into the intake while it is running. it is just abrasive enough to reseat the rings and then disintegrate. good idea to change the oil afterwards.
Dustin.

Offline MadScientist267

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Re: Generators gone wild...
« Reply #7 on: June 11, 2016, 06:17:30 am »
Hmm, might see what that's all about and even try it depending on what the camera says... Still waiting on that before I start yanking things apart again. Any good tricks like that to unplug the PCV as well? I strongly suspect that's a very possible cause as things sit right now... if I do tear into it after having to remove it from the truck, I'll be replacing it regardless, but would like to know ahead of time what the more and less likely situations are... and of course, as you may know, that valve is held behind the black layer of cooling duct plastic in there and is completely inaccessible except by the fuel pump vac line and PCV breather hose.

There's another (rather messy) experiment I want to repeat because my intent at the time wasn't diagnostic with it - and that's to crack the oil fill back open like I did when I was looking to bleed off excess oil... I seem to recall the smoking stopped while it was open, or at least became minimal. If so, more reinforcement for PCV stuck theory...?

Steve
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Offline bj

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Re: Generators gone wild...
« Reply #8 on: June 12, 2016, 07:01:08 am »
    I know people that swear by the Bon Ami trick.   I however have never been brave enough
to try it.  Theory is good though.
    Is there room to put an extension on the oil fill tube?  Might stop some of the oil spray, and prove
the point.  Any reduction at all in exhaust smoke would prove the point.
    That just triggered another thought------The PCV hose goes to the air intake between the filter
and engine.  If you can disconnect it from that point temporarily, and run it, you should have a
continuous pulsing flow from it.  No oil in the flow.  Anything other than that says valve is defective.
"Even a blind squirrel will find an acorn once in a while"
bj

Offline MadScientist267

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Re: Generators gone wild...
« Reply #9 on: June 15, 2016, 12:33:38 pm »
I wish I could figure out a suitable way to put an extension on it anyway... there are a couple of reasons I could think of that it would be beneficial to do so... That's just another to add to the list.

Maybe I can find a suitable piece of tubing that I can just shave down or whatever to get a halfway decent seal and connect the other end into some kind of rigged trap to test.

Losing faith in the idea that a bore cam is going to show up nearby, ugh... but the PCV "bypass" test would supersede it anyway, like you said.

Hopefully soon... things are kinda nuts at the moment... just changed over to summer mode and a lot [more than usual] of my stuff is in the storage unit. At least the days are long and the idea of overkill on the roof is panning out for the most part at the moment. I did ok it seems on fault tolerance for the most part, but of course now that I've said that... :o

Steve
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Offline Pete

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Re: Generators gone wild...
« Reply #10 on: September 11, 2016, 04:52:01 pm »
Hi Steve, if the generator has been running on light loads most of the time then glazing of the bore could be a possibility. Other than that I reckon you will find the rings are stuffed.  You could try putting a bit of oil down the spark plug hole, then leave it to see how long before it disappears. If the oil stays a long time turn the engine over a couple of times and see if it stays on top of the piston. If it disappears then the rings are worn out. If the oil is still there then you may be looking at valve stem seals or worn valve guides. Generally the amount of carbon shown in your pic means get the spanners out.
The next step is to pull it apart. I have tried the bon ami thing in the past, really the best thing is to pull the engine down, if the bore is not too worn( no big lip at the top) then hone the bore and put new rings in. By the amount of carbon on your spark plug I reckon the rings are most likely broken, or really worn.
Running the engine briefly with the oil filler plug will tell you if the rings are badly worn. There will be smoke and lots of oil flying out the hole. A piece of plastic tube shoved in the filler hole will help in diagnostics, keeps the mess level down a bit.
good luck
I hope mad scientist status means you are au fait with spanners.
Pete

Offline Norm

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Re: Generators gone wild...
« Reply #11 on: September 12, 2016, 08:20:25 pm »
Hey on my 18hp .....lot and lots of oil all over after a lot of figuring .....
take the OHV head off and guess what ?  all that because of a blown head gasket......new head gasket and runs like new no smokin now
maybe your problem also ?
Norm.
( fixed dozens of lawnmowers but still don't consider myself an expert )  :)

Offline MadScientist267

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Re: Generators gone wild...
« Reply #12 on: October 08, 2016, 12:22:11 pm »
Indeed things to check for... unfortunately I have very limited resources and it's most important that it be available even if that means "constant excessive maintenance requirements"

I finally had to shell out the 5 bucks for a new plug, and a spare... the original failed recently with first a memo involving a hard start, then 2 runs later, it caught what I believe amounted to a "minimal flood", and popped all of a dozen times total in the attempts to start it, but ultimately bridged the gap. Replacement went in, gapped, and first pull, little puff of blue and then was ready to rock and roll like nothing ever happened.

Here's a shot of the new plug after about 8 hours at 25~30% load, not allowed to idle except briefly after start (less than 30 sec or so) and for about as long after a no load eco off cool down, the full speed run lasting for between 2 and 3 minutes, trying to keep the exhaust clear while it gets good air flow but not doing anything. Best compromise I could come up with.

6239-0

Sorry about the file size, new phone does screen shots (EZ zoom lol) only in PNG and the resolutions are only getting bigger with time lol... haven't gotten around to working out the new resizing challenges it poses with a phone... sigh

Anyway, Hurricane Matthew is eyeballing us, Gotta get things back ready to roll for the next run. No real perceived danger at this point, it's done landfall and swapped out an eye already, gonna likely just be the usual "didn't know there was this much water in the universe nevermind in the sky" routine.

Til next update...
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