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


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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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