# RPM adjustment



## Cgreencorn1 (Sep 5, 2018)

Hello all, 

I have a HSS1332 new with less than 1 hour. I have replaced the original 102 jet with a 110 jet as per all the reading i have done. 

I checked the RPM today and at low speed its 2200rpm and high speed it tops out at 3400 RPM. I have no play in the cable to increase the rpm, should i adjust it to get the 3600 nominal speed and is it adjusted with the screw below air cleaner closer to handle bars?


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## Cgreencorn1 (Sep 5, 2018)

This is a pic of the screw i believe i should adjust to allow me to get to 3600 rpm at wot. 
Item number 12.


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## panzer (Mar 25, 2018)

Yes just back out screw 12. I am a little braver set mine to 3750 rpm.


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## Cgreencorn1 (Sep 5, 2018)

panzer said:


> Yes just back out screw 12. I am a little braver set mine to 3750 rpm.


Great, its 3550 +/- 150 correct? It appears when i load the motor by ingaging the auger there is very little RPM increase.


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## panzer (Mar 25, 2018)

Cgreencorn1 said:


> Great, its 3550 +/- 150 correct? It appears when i load the motor by ingaging the auger there is very little RPM increase.



Always set with no load, quite a few guys run up to 3900 rpms. The ignition will stop you at 4k rpms. If I am wrong someone please correct me.


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## tabora (Mar 1, 2017)

Actually, per the HSS1332A Service Manual it's officially 3,550 +0/-150 - That's 3,400 to 3,550 max, and FINAL Operating speed range is 50 RPM below those ranges: 3500 +0/-150 = 3350 to 3500 (nominal - see service manual pages attached). However, I set mine at 3650 and am happy with that. The torque starts to drop off pretty fast after that.


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## mmosberg (Feb 9, 2016)

Just bought a new HSS 970A ETD (the European version of the HSS 928).

I am going to check that the fast idle is at spec, 3650 rpm +0/-150. Furthermore I understand that slow idle is to be 2200 rpm +150/-150. Is there any downside of adjusting the throttle travel downward to for example 1200 rpm? Will for instance lack of lubrication come into play?


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## JLawrence08648 (Jan 15, 2017)

Honda, OHV, I'd set it at 3,650-3,700 rpm. I think there is significant improvement in throwing for every 100 rpm.


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## 1132le (Feb 23, 2017)

JLawrence08648 said:


> Honda, OHV, I'd set it at 3,650-3,700 rpm. I think there is significant improvement in throwing for every 100 rpm.



correct
impeller rpm goes up around 30 rpm for every 100 in engine rpm depending on factory setup
increased impeller rpm more then makes up for lost torq as long as you have enough motor


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## tabora (Mar 1, 2017)

mmosberg said:


> Furthermore I understand that slow idle is to be 2200 rpm +150/-150. Is there any downside of adjusting the throttle travel downward to for example 1200 rpm? Will for instance lack of lubrication come into play?


The output voltage from the coils would be pretty low at 1200. Could cause issues? I would keep it @ spec.


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## mmosberg (Feb 9, 2016)

Installed a digital tachometer on my HSS 970A ETD today. High idle was 3500 rpm and idle was 2200 rpm. Adjusted to 3650 rpm and 2000 rpm respectively.


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## Lake Effect (Jun 13, 2017)

What are you guys using to check rpm? I have an old auto dwell/tach tool but my HSS928ATD plug wire isn't as user friendly to hook up.


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## RIT333 (Feb 6, 2014)

Lake Effect said:


> What are you guys using to check rpm? I have an old auto dwell/tach tool but my HSS928ATD plug wire isn't as user friendly to hook up.



You need an inductive tach that picks up the signal with a wire that is wrapped around the plug wire.


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## 1132le (Feb 23, 2017)

Put a mounted tach/ hour meter on the 28 inch 414cc today high reading 3840rpm low reading 3780 rpm 2040 idle

Going to be interesting to see what the rpms do in a full bucket eod wet load
haven't swapped the .46 jet in yet for the stock .448


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## jsup (Nov 19, 2017)

Lake Effect said:


> What are you guys using to check rpm? I have an old auto dwell/tach tool but my HSS928ATD plug wire isn't as user friendly to hook up.



https://gtc.ca/Products/TA100.html


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## Lake Effect (Jun 13, 2017)

I didn't realize those digital hr/rpm meter were so cheap.


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## groomerz (Feb 7, 2015)

Treysit tachometer/sirometer made in west Germany sold with a brigs 19200 or tec 670156. Old school mechanical fits in top draw of tool box lasts for 20 years no batteries. Works by holding against outside of motor . 
Here is a video 

 https://youtu.be/TB-YeMOdGeg


Sent from my iPhone using Tapatalk


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## jsup (Nov 19, 2017)

groomerz said:


> Treysit tachometer/sirometer made in west Germany sold with a brigs 19200 or tec 670156. Old school mechanical fits in top draw of tool box lasts for 20 years no batteries. Works by holding against outside of motor .
> Here is a video
> 
> https://youtu.be/TB-YeMOdGeg
> ...



I looked into those, they were $500-700, so I got the TA100 I listed above. 



Sticht 6239 Vibrating Reed Tachometer 1000 to 5500 rpm from Davis Instruments


Do these work the same way?


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## groomerz (Feb 7, 2015)

The round treysit tachometer is like 25$ and last a lifetime


Sent from my iPhone using Tapatalk


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## Lake Effect (Jun 13, 2017)

Picked up a Runleader tach/hour meter off amazon for $22 shipped. Found full throttle at 3800rpm, 2210 idle. Hasn't been adjusted from new, only a #92 jet installed. Dialed it back to 3600rpm, left the idle speed alone. Next snow I'll see if it lugs down more.


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