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So the stock jet on a new GX390 snowblower is #102.
What were they using on older GX390 equipped blowers before they went too lean?



On a side note, I've seen a lot of mention of drilling jets.
I wouldn't even consider it as drills do not produce clean or round holes, for that you need a reamer and it really can't be done by hand as you want to ream perfectly straight. If you look at a drilled hole closely, it's pretty much trashed for anything that needs precision like a jet.

I'd always recommend buying properly sized jets.
ive been inspecting more jets. another gx390 off another pressure washer....oem carb- untouched.....105 jet. super easy to start. not a hint of lean misfire.
another unit......not marked, aftermarket carb.....also seems to be very similar sized.....

another gx390 oem carb had a 92 jet.

i have a china clone 440cc......that has a 100 jet in it...and its quite hard to start, needs choke everytime.

draw your own conclusions.....

next time I pull off my carb on the ariens ax306...ill inspect that. that thing runs like a top, 1/2 a pull already running.......
 

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ive been inspecting more jets. another gx390 off another pressure washer....oem carb- untouched.....105 jet. super easy to start. not a hint of lean misfire.
another unit......not marked, aftermarket carb.....also seems to be very similar sized.....

another gx390 oem carb had a 92 jet.

i have a china clone 440cc......that has a 100 jet in it...and its quite hard to start, needs choke everytime.

draw your own conclusions.....

next time I pull off my carb on the ariens ax306...ill inspect that. that thing runs like a top, 1/2 a pull already running.......

To me, I expect a properly jetted carb to need at least partial choke to start cold. If it was just shut off I'd expect it to start without it.

My Predator 420 has a #101 and will not start without choke even hot.

I had considered getting some pin gauges to check the jet to see if it's really 1.01mm.
 

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To me, I expect a properly jetted carb to need at least partial choke to start cold. If it was just shut off I'd expect it to start without it.

My Predator 420 has a #101 and will not start without choke even hot.

I had considered getting some pin gauges to check the jet to see if it's really 1.01mm.

cold? yea.....choke.
warm--hot....should not.

I have a 420cc here too...that had a 95 jet. just bought me an assortment of jets...ill be playing....

just ran the Little wonder 13hp...its 45f.....105 jet. runs like a thief in the night.
 

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cold? yea.....choke.
warm--hot....should not.

I have a 420cc here too...that had a 95 jet. just bought me an assortment of jets...ill be playing....

just ran the Little wonder 13hp...its 45f.....105 jet. runs like a thief in the night.
105 jet with or without an air filter?
 

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So the stock jet on a new GX390 snowblower is #102.
No, that's not what I said. Older machines had the #102 as stock. It's now a #110, same as what many of us upgraded ours to, effective with the /A rev at serial number SAFA-2000001. They also closed up the pilot jet screw a bit to compensate. I've kept mine at 2 turns out.
 

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No, that's not what I said. Older machines had the #102 as stock. It's now a #110, same as what many of us upgraded ours to, effective with the /A rev at serial number SAFA-2000001. They also closed up the pilot jet screw a bit to compensate. I've kept mine at 2 turns out.
Ahh. . I'm sorry I misunderstood.
 

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No, that's not what I said. Older machines had the #102 as stock. It's now a #110, same as what many of us upgraded ours to, effective with the /A rev at serial number SAFA-2000001. They also closed up the pilot jet screw a bit to compensate. I've kept mine at 2 turns out.

tabora,
Any idea if Honda uses a different pilot jet in their cold weather machines, or if it's the same exact one used in all of the GX390s etc?
 

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tabora,
Any idea if Honda uses a different pilot jet in their cold weather machines, or if it's the same exact one used in all of the GX390s etc?
For the HSS1332 / GX390 the Pilot Jet is:
99204-ZE0-0450JET SET, PILOT (#45)
For the GX390 on an EB7000 generator, for example, it would be a #40...
 
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Help at elevation

I'm at 6150 feet in elevation and I have a hss724a that was constantly bogging down with wet snow. It would constantly clog in the chute and would come to a stop. I found this snowblower forum from google searching for answers, and I found others with my issue.

I was able to get the new chute design replaced from honda under warranty. While it was there, I talked with service about getting a larger jet put in and provided them the link to this long rejetting thread. They asked where I lived, and gave them my address and altitude. They said they'd take care of it for like $25 in parts/labor and give it some additional power with a new jet while they did the chute swap. I said that's fine and had them do it.

I fired it up these last few days while we had snow, and the thing is bogging down worse than before with small amounts of snow. Even "dry" snow seems to choke it out and make the thing bog. It just sounds like the engine is struggling. I pulled up the invoice sheet and I see they went down to a 72 jet from the 75 factory. I see honda says to do that for certain altitudes, but clearly this did not help me.

I see another user listed the various jets for the hss724a, and it has a 78 above the factory 75, but maybe that won't help with my altitude? Do you think I should just go back to the 75, or buy both a 75 and a 78 and see what happens at this point? I haven't adjusted anything with the throttle from factory, but I do own a throttle gauge that I've used to adjust my honda mower. I could toss it on the blower to see what it's running at.

I appreciate any input others may have at altitude
 

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Do you think I should just go back to the 75, or buy both a 75 and a 78 and see what happens at this point?
Yes, I would think a #78 (or larger) is the right direction if a #75 was bogging and a #72 is worse. Maybe try first a #78 & then a #80 if needed?
 
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I moved from a #75 to a #78 on my HSS724 just recently and it runs better, but I am at 200'.

I installed an hour meter/tach this week. Running 3720 RPM at full throttle with no load. Going to bump that up to 3850. The throttle screw is not easily accessed. Will pull off air intake cover this week and bump the RPMs up. No real snow yet on the East Coast.

I would be very interested in your results at #78 at your altitude. I am tempted to try the #80.
 

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I moved from a #75 to a #78 on my HSS724 just recently and it runs better, but I am at 200'.

I installed an hour meter/tach this week. Running 3720 RPM at full throttle with no load. Going to bump that up to 3850. The throttle screw is not easily accessed. Will pull off air intake cover this week and bump the RPMs up. No real snow yet on the East Coast.

I would be very interested in your results at #78 at your altitude. I am tempted to try the #80.
Why are you increasing the rpm?
 

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Going to bump that up to 3850.
Beware getting close to 4K RPM. The voltage for the LED light will go over-limit and will nuke your lamp assembly. There's actually a warning in the shop manual about that.
Rectangle Font Parallel Magenta Circle


Rectangle Slope Plot Parallel Font
 

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I couldn't seem to find the RPM for the HSS724 in the owners manual. I don't have a shop manual yet.

I was able to find online a Honda "Dealer Instructions for Set-Up and Pre-Delivery Service" Manual for the HS Series. It listed the set-up RPMs as follows:

Use a tachometer to check the maximum governed rpm with
the throttle lever in the FAST position and auger clutch lever
disengaged.
MODELMAXIMUM RPM
HS6243,800 ± 150 rpm
HS7243,850 ± 150 rpm
HS828
HS928
HS1132
3,600 ± 150 rpm

I was assuming the HSS724 is the same as the HS724. Appreciate any intel, particularly if anyone has a shop manual.
 

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The HSS724 service manual states that the maximum engine speed at no load is 3800 +0/-150. Idle speed is 2100 +/- 150. Be mindful of the range notation difference.

This is most helpful. Is is worth bumping up from 3720 to 3800 RPM? I appreciate that it is within range, but I recollect others noting that a 100 RPM gain makes a difference.

I can disconnect LED while making the adjustment.
 

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The HSS724 service manual states that the maximum engine speed at no load is 3800 +0/-150. Idle speed is 2100 +/- 150. Be mindful of the range notation difference.
My HSS724 manual, the same page, lists both 3800 and 3850 (+/- 150) I should take a picture. Anyway, when new last year it both took multiple cranks to start and surged until warm. I put in a #80 jet in the off-season at my 700 ft. altitude. It now easily starts on first crank. I have to move it out of full choke within seconds or it will stall. At half choke it does push out some grey smoke, but once started I can move immediately to low idle with no issue. It purrs like a kitten at both high and low idle now with no smoke whatsoever and no surging. My tach did go to 3850. I did adjust the cables slightly and brought full throttle down to about 3830… leaving it there for now. My idle screw is nearly all the way out but idle is at 2200. Close enough for me. Unfortunately, no plowable snow yet for me this year and no artic temps yet. I look forward to trying to start in really cold weather to see the impact. I have Stabil in my Midwest ethanol fuel, and battery on the Optimate 4. I start and run the engine for about 5 minutes each weekend. I should probably check the plugs to see if current setup is too rich. I’ve been debating whether the #78 is more ideal? I had bought that as well at the same time. For now, I’ll leave as is. Looking forward to the first big snow. Worst winter I’ve ever seen for snow in 20 years where I’m at (go figure). All the snow hitting about 2 hours north of here.
 

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Keep in mind when you go to winter use you need a larger jet to adjust for the more oxygen rich air. So the stock size may be intended for summer use. The size of the carb throat is a factor too. I have found with aftermarket carbs the throat diameter can be a bit larger and the jet needs to be adjusted to keep it from surging. Good Luck!!!!
 
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