# Generac iq2000 frankenstien build help



## Theeonlyduck (Dec 1, 2021)

So I acquired a non running generac iq2000, it needed a led board, I was getting extremely weak spark and could never get it to run at the correct speed it would run but extremely slow and then die, maybe 3 sec max. Anyway we are way past that, I've removed all electronics except inverter board. I Installed a pit bike cdi 12 volt, used 3 lithium batteries in series to power it up and when it's running it takes the 120 volt to a small lithium charger to keep the battery full at all times. Now it has very strong spark and engine runs and output power to outlet is 122 volts at 61 hz.

You ask so what's the problem?
Well I'd runs like it's missing and is not smooth at all. It should basically run like a honda eu2000 if you have heard those just purrr smoothly. I know this gen can do that I just don't know what else at this point to try. It runs and handles a load and everything but runs very shaky and vibrates you can here a miss. I'll try to upload a video

I've changed oil
New Air filter
Set valve lash to spec
Replaced spark plug
Fresh gas
Cleaned carb 4 times now most recent was with a ultra sonic cleaner(carb didn't have any bad gas in it anyway).
Opened head and checked it out, extremely clean.
The original pick up works for the signal wire to the csi box unless it's not getting the correct constant signal. 

I've been an rv tech for 20 yrs. I have never been stumped by anything but this. I've cleaned a thousand carbs successfully. I fixed tons of rv generators. Just started messing with portable to keep myself busy after hours.

Could the spark be to hot, is that a thing I've fixed a ton of generators but never installed a cdi box to piece something together that was otherwise junk.

Please help. I'm sure someone here is smart enough to figure it out.


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## OrlyP (Oct 19, 2021)

How many hours does it have? How's the compression?


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## Theeonlyduck (Dec 1, 2021)

No info on hours, but I completely took everything apart and piston head and valves were so clean like it ran for a max of 15 minutes for the life of it. Has a compression relief and I get 60 on the gauge.


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## OrlyP (Oct 19, 2021)

You clearly know what you're doing. All I can offer you are the usual suspects.... Does it improve if you give it some choke?

Assuming that fuel delivery and compression are not the problem, misfiring could be due to timing or intermittent spark. The problem is likely something ridiculously simple as a faulty HV cable, for example.... or a sheared shaft key or even timing marks on the gears not matching up.

I hope you can upload a clip of it running.


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## iowagold (Jan 22, 2020)

Theeonlyduck said:


> So I acquired a non running generac iq2000, it needed a led board, I was getting extremely weak spark and could never get it to run at the correct speed it would run but extremely slow and then die, maybe 3 sec max. Anyway we are way past that, I've removed all electronics except inverter board. I Installed a pit bike cdi 12 volt, used 3 lithium batteries in series to power it up and when it's running it takes the 120 volt to a small lithium charger to keep the battery full at all times. Now it has very strong spark and engine runs and output power to outlet is 122 volts at 61 hz.
> 
> You ask so what's the problem?
> Well I'd runs like it's missing and is not smooth at all. It should basically run like a honda eu2000 if you have heard those just purrr smoothly. I know this gen can do that I just don't know what else at this point to try. It runs and handles a load and everything but runs very shaky and vibrates you can here a miss. I'll try to upload a video
> ...


use an inline spark tester and look at the spark to see if it is a fail to spark issue.
they also make fancy scope spark testers it might be worth it to see if it is missing fire part of the time.

also try a new carb.
yea these days a new carb is not that expensive...
unless you have a flow bench you cannot see the AF exact mix ratio.


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## Theeonlyduck (Dec 1, 2021)

OrlyP said:


> You clearly know what you're doing. All I can offer you are the usual suspects.... Does it improve if you give it some choke?
> 
> Assuming that fuel delivery and compression are not the problem, misfiring could be due to timing or intermittent spark. The problem is likely something ridiculously simple as a faulty HV cable, for example.... or a sheared shaft key or even timing marks on the gears not matching up.
> 
> I hope you can upload a clip of it running.


Checked gears and timing all set correct, I'm just confused why the cdi box would give it intermittent spark...if I choke it at all It will start to die out, so maybe more fuel? I could drill out the jet one more size and see what happens. I can't tell if its to lean or not. Carb has a servo on top and is controlled by the inverter board (basically the governer) and when loaded ramps up and unloaded ramps down all seems to be working great but can get the shake out of the unit. I'll check spark on adapter and see if it's inconsistent next. I don't wanna drill jet, no coming back from that lol 😆


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## Theeonlyduck (Dec 1, 2021)

iowagold said:


> use an inline spark tester and look at the spark to see if it is a fail to spark issue.
> they also make fancy scope spark testers it might be worth it to see if it is missing fire part of the time.
> 
> also try a new carb.
> ...


When I originally had inverter disconnected and I could throttle it myself it would run at high speed, didn't sound like a miss but back to an idle still controlled by myself it def runs exact same as everything hooked up, that's what makes me think It may be a tad lean. Maybe not. When I first start it I cannot take full choke off or it hiccups worse and that would be a more rich scenario. So I'm confused on that part, must be cdi box picks up funny signal from flywheel. I don't know if the pickup outputs 12 volt or 110 volt to cdi box to tell it when to fire. I do remember metering it and getting 1.4 volts dc from pickup when spinning with a drill. It has to be cdi box not meshing well with flywheel pickup. I dunno how to match that up as a frankenstien build. Anyone know what voltage the cdi box should see on the signal wire? 🤔


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## drmerdp (Apr 10, 2018)

Does it stumble when the side cover is removed?


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## OrlyP (Oct 19, 2021)

Theeonlyduck said:


> Checked gears and timing all set correct, I'm just confused why the cdi box would give it intermittent spark...if I choke it at all It will start to die out, so maybe more fuel? I could drill out the jet one more size and see what happens. I can't tell if its to lean or not. Carb has a servo on top and is controlled by the inverter board (basically the governer) and when loaded ramps up and unloaded ramps down all seems to be working great but can get the shake out of the unit. I'll check spark on adapter and see if it's inconsistent next. I don't wanna drill jet, no coming back from that lol 😆


If it dies when you give it some choke, it means it does have enough fuel.... maybe a little too much. So right now, it's possible that it's running a little rich. Either there's too much fuel or there's not enough oxygen. Try fiddling with the A/F screw and see if it does anything. But do remember where it was by counting the turns going in until it stops.... you know the drill (no pun intended).


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## iowagold (Jan 22, 2020)

Theeonlyduck said:


> When I originally had inverter disconnected and I could throttle it myself it would run at high speed, didn't sound like a miss but back to an idle still controlled by myself it def runs exact same as everything hooked up, that's what makes me think It may be a tad lean. Maybe not. When I first start it I cannot take full choke off or it hiccups worse and that would be a more rich scenario. So I'm confused on that part, must be cdi box picks up funny signal from flywheel. I don't know if the pickup outputs 12 volt or 110 volt to cdi box to tell it when to fire. I do remember metering it and getting 1.4 volts dc from pickup when spinning with a drill. It has to be cdi box not meshing well with flywheel pickup. I dunno how to match that up as a frankenstien build. Anyone know what voltage the cdi box should see on the signal wire? 🤔


check the idle jet under the throttle lever
go one size larger.
pm if you need links to the special bits for that


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## Theeonlyduck (Dec 1, 2021)

drmerdp said:


> Does it stumble when the side cover is removed?


No stumble when side door is open


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## drmerdp (Apr 10, 2018)

Theeonlyduck said:


> No stumble when side door is open


The flywheel fan pulling cooling air through the engines primary shrouding is causing the engine air intake to get starved of air. A rich condition. You need more flow through the Intake slots in the front of the enclosure or the side cover to feed the engines intake.

I had the same issue with my eu1000.


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## Theeonlyduck (Dec 1, 2021)

Hers a video 



You can see playing with choke only kills engine. I have jet drill bits, do I need to increase main jet or idle jet? I though portable generator didn't use the idle jets...

Main jet at .026 thou
Idle jet at .015 thou

Here's a pic of spark plug, seems rich


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## iowagold (Jan 22, 2020)

try it with the air box cover and filter removed


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## OrlyP (Oct 19, 2021)

Definitely running rich. Either the jets aren't set correctly or the choke isn't opening fully.

With the engine off, try opening up the air box and remove the air filter. Observe whether the choke butterfly is opening up fully when you turn the knob to the Run position.


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## iowagold (Jan 22, 2020)

oh yea
drain all of the gasoline out, purge the whole system to total dry.
change the spark plug.
and fill it with fresh e-0 93 oct fuel and see if it is better!

runs like it has gezel in it!
(1/2 diesel and 1/2 gasoline)


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## Theeonlyduck (Dec 1, 2021)

Tank was empty I just filled it with 93 octane. 
Set intake and exhaust valves to .10 mm. 
Choke is 100% open, runs exact same with airbox and filter removed.
Brand new spark plug
Drilled out pilot jet from .015 to .017, made no difference. 
This thing is crazy. 
Who is in socal (long beach) that wants to come test their knowledge. You will feel defeated on this one lol. I would drill main jet but I can see it running rich from the looks of the plug. So that wouldn't help...I've had this thing together and apart at least 20 times now, nothing has made a difference. I'd bet 95% chance a new carb wouldn't make a difference. There was no trace of old fuel at all.


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## iowagold (Jan 22, 2020)

try a new carb
it could be a plugged emulsion tube jets or air bleed
that would give way way too rich.


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## Theeonlyduck (Dec 1, 2021)

I'm thinking I may be getting pre ignition, I noticed timing wasn't set to fire at top dead center. It fires about 17* before tdc. So I'm wondering that's prob good for original electronics but since I put in a cdi box it may need to be set to a degree closer to tdc, what do you guys think about that? Like say 10*. It's also running at 3600 rpm on the dot, weird.

The reason I feel it fires a bit to early is because sometimes when pull starting it yanks the pull cord from my hand violently...


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## iowagold (Jan 22, 2020)

yea if the ecm spark unit has a retard to start setting... that is always good.


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## Theeonlyduck (Dec 1, 2021)

Well new carb, same prob....
Took of caseing to see flywheel and pickup, here are photos where you see black line on case is top dead center compression stroke, but look how early it fires according to pickup. Way early. Sheer key is fine, proh with original electronics that would work fine but I'm useing a pit bike cdi box. Should I set it somehow at exactly tdc and try it out. I'd have to remove sheer key and add new to another spot I guess, never tried it before but hey learning is fun.


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## iowagold (Jan 22, 2020)

if it is a true key, they make off set keys.
most are for the drag race gx390 honda engines for kids
easy to make them if you have a full machine shop.

most of the fly wheels i have seen have a fixed key made in to the aluminum flywheel on the little engine gens.
unless it is a steel flywheel or cast iron.


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## Theeonlyduck (Dec 1, 2021)

Well, figured it out. So with original electronics is was okay spark at 15 degrees btdc. But this pit bike cdi box needed dead on top dead center so I was able to still use the key way on the crank and clock the flywheel, so it lined up tdc when firing, thing runs like a charm now. Wow when useing all aftermarket parts to make a frankenstien generator you basically have to start from ground up. Finally we are done! Thanks everyone for your inputs.


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