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Help with Carburetor Adjustment - 6.5NH-3CR/1600P


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  #1  
Old 03-16-2017, 02:17:17 PM
AppleTech AppleTech is offline
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Default Help with Carburetor Adjustment - 6.5NH-3CR/1600P

Love a little help here - just got my 6.5NH fired up for the first time since rebuild today.

I'm working on setting the carb per the manual:


Here's what I'm getting right now:
Un-touched idle (just for sound):
https://youtu.be/-xDMMGI-vF0

Voltmeter readings while holding governor back, no load:
https://youtu.be/rF8sAK35Tcg

Now, knowing that I haven't ever run a generator hooked up to a voltmeter before, I don't know if the jumpiness of these numbers is expected or if I should be trying to get a closer number? Is my idle bad or is this what they sound like? I'm curious what range would be acceptable for modern fridges and my AC unit as far as volts and hertz.

Any tips on a good procedure to tune this thing properly would be appreciated - this is the first carb I've touched!

---------- Post added at 01:17:17 PM ---------- Previous post was at 12:56:24 PM ----------

Also just to clarify - carb has been fully disassembled, cleaned, and resealed. I set the adjustment needles to the "default setting" as identified in the manual before starting the tuning procedure.
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Old 03-16-2017, 02:28:26 PM
Ben Cowan Ben Cowan is offline
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

experts will be along to advise. Seems like I remember others mentioning plugging in say one 60-75 watt light bulb. Small load can help meter stabilize your readings. worth a try. Luck, Ben
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Old 03-16-2017, 02:29:36 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

It should be steady and not hunting around (both voltage and frequency), you should use the procedure you have posted. Make sure when you adj. it loaded you have a fairly decent load close to it's rating on it. Then see how it runs without a load.

Last edited by nothingbutdarts; 03-16-2017 at 02:30:29 PM. Reason: added info.
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Old 03-16-2017, 02:34:42 PM
Jim Rankin Jim Rankin is offline
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

You are going to have to watch an analog (needle) type meter to accomplish that procedure. Or else get the meter to settle down. You might try a small load like an incandescent lamp or trouble light and see if that settles it down any.

Alternatively, watch the frequency/listen for speed change instead of the voltage.

The engine never runs at the low idle speed you are setting, so I would say those settings aren't very critical, though they have something to do with response to load changes. The high speed/under load settings need to be under FULL load to get the best response to the changes in adjustments. Once you have some run time you can look at spark plug deposits color to judge how well you did on the high speed mixture.
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Old 03-16-2017, 02:54:06 PM
AppleTech AppleTech is offline
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

Quote:
Originally Posted by Jim Rankin View Post
You are going to have to watch an analog (needle) type meter to accomplish that procedure. Or else get the meter to settle down. You might try a small load like an incandescent lamp or trouble light and see if that settles it down any.

Alternatively, watch the frequency/listen for speed change instead of the voltage.

The engine never runs at the low idle speed you are setting, so I would say those settings aren't very critical, though they have something to do with response to load changes. The high speed/under load settings need to be under FULL load to get the best response to the changes in adjustments. Once you have some run time you can look at spark plug deposits color to judge how well you did on the high speed mixture.
Thanks I will try that and use an analog meter to avoid crazy jumps that should help with getting me to set it right.

I'm kind of at a loss as to what to use around the house to try and get it to full load. Any thoughts off the top of anyone's head?
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Old 03-16-2017, 03:31:11 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

electric space heaters and blow dryers. Second hand stores sell hair dryers really cheap and they range in the 1,000 to 1,600 watts.

Last edited by nothingbutdarts; 03-16-2017 at 03:31:29 PM. Reason: spelling
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Old 03-16-2017, 06:54:04 PM
squidtrap squidtrap is offline
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

toaster oven is good if u dont have enough loads, can even cook lunch, best of both worlds.
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Old 03-17-2017, 12:29:03 PM
AppleTech AppleTech is offline
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

OK - so today I reset the carb back to factory settings for the idle and main screws.

Initially I got it to fire up OK and generate roughly 100v with me holding back the governor. Was getting 120v at idle. When applying small loads (greater than 60w, but below 1kw), it was hunting a bit. Once I put a 1850w hair dryer it was hovering steady at 120v and reacted well when powering it on and off. I added my electric air compressor (not sure of W) and it was OK.

The issue I'm having is with the idle and main mixtures. As soon as I mess with those it doesn't run well and doesn't hold V properly. Adjustments of the idle screw seem to not make much difference no matter how far I turn it (I was afraid it was going to pop out at one point I had backed it out so far). I just want to make sure its not set to run too rich because the motor had a ton of carbon buildup when I rebuilt it, so I'm wary of setting it incorrectly.

I also noticed the set tends to run smoother around 140v - when I get it down to 120v it vibrates much more, so maybe that is an indicator that the mixtures are incorrect?

Should I just aim to fiddle with the mixtures until it runs smoothly at low, mid, and high load?
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Old 03-17-2017, 02:24:56 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

For starters what you really need to do is get a Kill A WATT meter and use hertz readings, not voltage for setting it up, they are cheap like $25.00 - $30.00.

When it's running with no load is the throttle lever touching the IDLE SPEED adjustment screw at all?
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Old 03-17-2017, 02:45:35 PM
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

Quote:
Originally Posted by nothingbutdarts View Post
When it's running with no load is the throttle lever touching the IDLE SPEED adjustment screw at all?
It was initially, then it got tuned to a bad state where it wasn't and was still putting out 120V.

I'll try and tune it on hertz and look into getting a KW meter.

Also - is this what you are referring to?

https://www.amazon.com/P3-P4400-Elec...l-a-watt+meter

Does this detect KW on what is going THROUGH it or what is on the line? Need to make sure it is OK for me to pass a full load through?
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Old 03-17-2017, 03:26:22 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

Yes, that is exactly what I am talking about. It will read HZ, amps and KW.
Be aware! It is only good for 15 Amp and like 1,600 KW so you can plug usually one hair dryer into it and watch what it is drawing amp and KW wise.

The IDLE SPEED SCREW should NEVER touch the throttle linkage lever. There might be a MOMENT the governor will let the throttle lever come back and touch the idle screw but, that would only be when the the generator is close to fully loaded and all the load is instantaneously shut down. The throttle would come against the idle stop till the RPM/HZ got back down to around 61 HZ then it will come back off the idle screw. Most likely so quickly you would never see it happen.
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Old 03-17-2017, 03:29:55 PM
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

Quote:
Originally Posted by nothingbutdarts View Post
The IDLE SPEED SCREW should NEVER touch the throttle linkage lever. There might be a MOMENT the governor will let the throttle lever come back and touch the idle screw but, that would only be when the the generator is close to fully loaded and all the load is instantaneously shut down. The throttle would come against the idle stop till the RPM/HZ got back down to around 61 HZ then it will come back off the idle screw. Most likely so quickly you would never see it happen.
Right but when I hold the governor completely forward for baseline, it is supposed to rest on it - that's why you set it per the manual anyways. It wasn't sitting on it while governor was doing its thing. Sorry I probably wasn't being clear.
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Old 03-17-2017, 04:30:28 PM
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

Quote:
Originally Posted by AppleTech View Post
Right but when I hold the governor completely forward for baseline, it is supposed to rest on it - that's why you set it per the manual anyways. It wasn't sitting on it while governor was doing its thing. Sorry I probably wasn't being clear.
You are good to go then and did it like the manual!

I have had troubles before trying to get a governor set only to find out the idle speed screw is screwed in to far.
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Old 03-22-2017, 11:07:51 AM
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

Ugh I am still struggling with this. I gave up on mixing at base idle because the idle screw never really did anything other than cause the unit to run above 120v, even holding the governor back. I could get it to hover around 100v but as soon as I turned the mixture screw out it ramped up to 120+v and never dropped back (never indicated a rich mixture). I was afraid the screw was going to back all the way out.

I got it to idle well on gov control at 120v/60hz (+/- 3v/hz at most) and adjusted idle mixture there. However when putting a small load (1875 hair drier) it is dropping to 115v and staying there. Not sure what adjustment to make as that is the governor, right? Main mixture screw didn't really seem to do anything cranking it back a couple turns... I do want it adjusted properly around 2000W as my main electric needs (2 fridges and some lights) will cause it to hover around there.

Is my expectation that small adjustments to the mixture screws (1/2 or full turns) should yield results or do they really need to be cranked a lot to elicit change? Appreciate any help...
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Old 03-22-2017, 02:21:15 PM
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

I guess the part I'm confused about is idle speed mixture adjust. It never gets to the part where the manual says "when too rich, speed/voltage will drop" - it just ramps the speed up when I dial back the screw...
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Old 03-22-2017, 02:35:32 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

In my opinion, heck with the idle mixture adj. screw for the time being!
A 1,800 watt load should not bother a 6.5NH much and it should be more than capable of keeping the voltage above 115 volts. We need to know with the 1,800 watt load and the RPM/voltage is dropping, when it levels off there what happens when you grab the throttle and go wide open with it? Will the voltage come up towards 120 or more volts????
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Old 03-22-2017, 02:41:41 PM
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

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Originally Posted by nothingbutdarts View Post
In my opinion, heck with the idle mixture adj. screw for the time being!
A 1,800 watt load should not bother a 6.5NH much and it should be more than capable of keeping the voltage above 115 volts. We need to know with the 1,800 watt load and the RPM/voltage is dropping, when it levels off there what happens when you grab the throttle and go wide open with it? Will the voltage come up towards 120 or more volts????
Well yes when I grab throttle up volts go up (saw as much as 200 when I was fidgeting with it) but since this is mechanically governed we really only expect it to maintain 120v at a specific RPM. The trick is keeping it there at idle, mid load, and high load... right?
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Old 03-22-2017, 04:19:22 PM
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

Specs.
63 HZ no load and 59HZ full load.

Did you get a Kill A WATT? No load HZ reading should be 63HZ, what is it??? The governor needs to be the syst. holding it at 63 HZ no load, not the idle speed screw. Just asking.
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Old 03-22-2017, 04:28:27 PM
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

Quote:
Originally Posted by nothingbutdarts View Post
Specs.
63 HZ no load and 59HZ full load.

Did you get a Kill A WATT? No load HZ reading should be 63HZ, what is it??? The governor needs to be the syst. holding it at 63 HZ no load, not the idle speed screw. Just asking.
Didn't get a KillaWATT yet but my meter no load was hanging around 60Hz so I will have to adjust.
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Old 03-22-2017, 05:16:11 PM
JohnnyC JohnnyC is offline
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Default Re: Help with Carburetor Adjustment - 6.5NH-3CR/1600P

I'm jumping into this thread a bit late and forgive me if the questions I will be asking were already answered ---

1) In your opening post you mentioned "- just got my 6.5NH fired up for the first time since rebuild today." Is the rebuild just a carburetor or the entire generator including the carburetor?

2) Which carburetor do you have? Nikki?

3) Did your 6.5NH run to spec before the rebuild?

4) Did you know that the intake manifold is a 2 piece manifold and is known to develop vacuum leaks which can affect the performance. Are you 100% sure there are no leaks in the 2 piece manifold?

I have the same 6.5NH. I rebuilt Nikki and Walbro carburetors (and in some cases many times over while experimenting). I had several RV gensets that had the leaking 2 piece manifold. Once I repaired the leaks and FULLY rebuilt the carburetors I never had any issues running the carburetors set to the factory adjustment recommendations. I just rebuilt my 6.5NH's carburetor twice in a 2 weeks time span because my Facet fuel pump puked up it's internal rubber components due to deterioration which plugged up the carburetor in both cases.

JohnnyC
New Jersey
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