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From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Q for owners of inverter style gensets
Date: Mon, 26 Mar 2007 19:39:29 -0400
Message-ID: <>

I don't know about the Kipor in particular but in general,
oscillations like that are caused by a too-lean mixture.  In the past
that was usually due to gunk coating the inside surfaces of the jets
and effectively reducing their flow area.  Now it's usually because of
the EPA small engine emission rules.  OHV engines can generally squeak
by by running a very lean mixture.

Is there any sort of altitude compensation on the carb?  If so setting
it for sealevel will richen it up.  Because of EPA there probably
aren't any mixture screws on the carb.  If there are, try enrichening
the low speed mix a little, maybe a half-turn on the screw at a time.

If there are no screws, an indirect way of richening the mix is to
slightly raise the float level.

You might also see if slightly damping the stepper will stop the
oscillation.  Try gently resting your finger on top of the carb
throttle shaft so that friction between the shaft and your finger
resists motion.  Too much pressure will make the oscillations worse
but just a little might damp the oscillations.  If this works then we
can figure out how to mechanically damp the thing.

You might also look to see if the stepper arm has more than one hole
for the throttle linkage (assuming it has a stepper arm :-)  Moving
the linkage closer to the stepper shaft reduces the mechanical gain
and might be enough overall gain reduction to stop the oscillation.
The tradeoff might end up being more sluggish response to load step


On Mon, 26 Mar 2007 07:40:18 -0700, Mickey <> wrote:

>Recently purchased a small Kipor genset and so far is working ok.  Have
>noticed with little or no load the engine speed isn't consistent.  Took
>a look and have noticed the reason for the pulsing of the speed is the
>stepper motor is also pulsing.  Don't think it should be operating this
>way but I have very little experience with this type of genset.  My son
>has a Yamaha 2800 model and his does the same thing but don't know if it
>for the same reason.
>Anyone either have seen this kind of operation or heard of anyone that has?
>This is not a big issue but if it's not right, I do want to get it taken
>care of as it may be a sign of future controller problems.

From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Q for owners of inverter style gensets
Date: Tue, 27 Mar 2007 20:34:37 -0400
Message-ID: <>

On Tue, 27 Mar 2007 08:27:59 -0700, Mickey <> wrote:

>Thanks for the comments.  This is not a mixture issue.  I can get my
>finger into the area and feel what is happening.  Definitely the stepper
>motor is pulsing back and forth & is a fairly strong pulse.  I suspect
>is is an issue with the servo portion of the controller but with lack of
>experience and only other unit I have any real knowledge of doing the
>same thing, it raised the question of "could this be normal".

This IS a mixture issue.  What happens is that the mixture gets lean
enough that the engine drops speed.  The servo loop opens the
throttle.  The engine momentarily bogs a bit and then picks up.  By
then the servo has the throttle too far open so it closes it.  The
engine underspeeds and the process repeats.  That you can damp the
oscillation with your finger firms up my diagnosis.

Something to check to confirm.  Load the generator slightly until it
just stops oscillating.  Ideally the control loop will be on the edge
of oscillating - the stepper quivers back and forth but not enough to

Run it like that for awhile then kill the ignition.  Remove and look
at the plug.  I bet it'll be white as snow.  The best place to judge
the mixture, as opposed to the plug heat range, is about a mm from
where the insulator meets the shell.  There should be a fuzzy ring of
color down in the shell.  White is too lean.  coffee-with-cream is
just right.

Adjusting the mix via either method I described will completely
confirm (or not) my diagnosis and cure the problem.

>Purchased this at Harbor Freight and suspect they are ridding themselves
>of inventory since Kipor has changed their US distributor.  Paperwork
>that came with the genset said HF was the dist and to contact them for
>service.  Suspect with change in US dist they no longer are dist for
>this model.  Picked up the unit for $300 (new in sealed retail
>box)including a 2yr extended warranty good for swap or return money Vs
>actual repair.  Price was right, size is suitable for intended needs.
>Not ready for refund if they no longer have any inventory.

Hmm, I'd like to get one for that price.  Do you happen to have the
stock number?  I just searched their web site for "kipor" but no good.
I know that sometimes if one has the stock number he can order from
remaining inventory after the item has been removed from the site and
the catalog.


From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Q for owners of inverter style gensets
Date: Tue, 27 Mar 2007 23:16:06 -0400
Message-ID: <>

On Tue, 27 Mar 2007 22:45:41 -0400, Neon John <> wrote:

>On Tue, 27 Mar 2007 18:29:42 -0700, Mickey <> wrote:
>>Here you are on the item.
>>As for mixture problem, sorry you are wrong.  I'm a long ways from being
>>inexperienced with engine operation and carb issues.  Speed does not sag
>>prior to servo upping the throttle.  As I said in prior message, if I
>>prevent the servomotor from moving, the engine runs smooth as silk.
>>Initially my first thought was lean mixture and did richen up the
>>mixture some.  Made no difference that's when I started looking at what
>>was happening at the throttle.

Have you looked at your manual, at the troubleshooting section?

I just downloaded a copy here:

Sorry it took so long.  Darn dial-up!  On page 16 is a diagnostic tree
labeled "Engine speed does not increase or stabilize."  The first item
to check is the air cleaner (duh!)  The second is valve clearance.
That hadn't crossed my mind but yeah, that makes sense, especially if
the intake is tight.  Everything else in the tree is lean-mixture
related or low compression.  If all else fails it sends you to the
section to check the servo, Page 19.  Basically, check the wiring,
check the servo for free movement then replace the control module.

Still betting on lean mix if it isn't the valve clearances.


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