# HS55 engine speed



## bosco659 (Feb 1, 2013)

The owners manual for my HS55 states that the max engine speed for its GX140 is supposed to be 4,200 rpm. That sounds high to me as most small engines I have owned run at 3,600 rpm. Any thoughts? Currently set at 3,600 and am concerned I might damage it if I crank it up another 600 rpm. 
Thanks


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## orangputeh (Nov 24, 2016)

my manual states 4200 also. i'd keep it at 3600 if you are comfortable with it.

on the HS50 the max speed is only 1850-1950. i always wondered about that.


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## JimmyD (Nov 20, 2016)

orangputeh said:


> my manual states 4200 also. i'd keep it at 3600 if you are comfortable with it.
> 
> on the HS50 the max speed is only 1850-1950. i always wondered about that.


They're two completely different engines. 

The HS50 is the older flathead/side valve design, and the HS55 uses the GX OHV design. Flatheads don't like to rev freely or highly.


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## orangputeh (Nov 24, 2016)

JimmyD said:


> They're two completely different engines.
> 
> The HS50 is the older flathead/side valve design, and the HS55 uses the GX OHV design. Flatheads don't like to rev freely or highly.



thanks. i learn something new everyday here.


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## bosco659 (Feb 1, 2013)

Checked with our local Honda distributor tech and he said spec is 3900 +/- 100 rpm. I think I'll be conservative and keep it under 3900. After all it runs like a champ at that speed so no sense in pushing it too hard.


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## ER Guy (Jan 27, 2019)

*The max RPM is 3200 for Honda HS55*

I found your message online while I was doing a GX140 engine swap. I did see the Honda HS55 manual mentioned the max HP 5.5 @4200. But I also found the follow information on Honda GX140 owner's manual, it says max output 5.0 HP @ 3600 RPM, but very importantly the Max torque 7.7 lb-ft @2800 RPM. So with those information I went to a local Honda snowblower dealer with a long history, talked to service tech, I was told the Honda HS55 the Max RPM setting is 3200. He said the engine may surge when you set the RPM @3600. It makes a lots sense to me now. Max torque is more important for the snowblower.


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