New HRX Line

trekgod3 · Jan 28, 2019

dfwchief said:
What reading do you get from the tach? I've looked at the engine specs here https://global.honda/newsroom/news/2018/p180613eng-gcv.html

and it shows max HP at 3,600 rpm, and max torque at 2,500.

I actually haven't used the mower since installing the tach. I couldn't wait for it to be delivered before I used the mower. But , I will report back the next time I do. I should be using the mower on Wed or Thurs

stygz · Jan 28, 2019

I would think higher torque is more beneficial than HP when cutting grass

cruzenmike · Jan 28, 2019

stygz said:
I would think higher torque is more beneficial than HP when cutting grass

You are correct that the torque plays an important role in cut quality, especially under adverse conditions (damp/wet, long, fast ground speed). You will notice that some lawn and garden equipment such as snow blowers make no mention of HP and instead they are simply rated by torque.

stygz · Jan 28, 2019

cruzenmike said:
You are correct that the torque plays an important role in cut quality, especially under adverse conditions (damp/wet, long, fast ground speed). You will notice that some lawn and garden equipment such as snow blowers make no mention of HP and instead they are simply rated by torque.

This would leave me to wonder why raise the rpm on the mower? Doing so would also decrease engine life.

cruzenmike · Jan 28, 2019

stygz said:
This would leave me to wonder why raise the rpm on the mower? Doing so would also decrease engine life.

Because doing so increases the blade tip speed. Increasing blade tip speed creates more vacuum under the deck, cuts the clippings more often and discharges clippings at a greater velocity. I am not saying that everyone should go out and just increase the rpm of their engine, because it can and will lead to premature failure and in most cases increase the vibration which the user may feel through the machine/handles. But in the case of the HRX line, there were machines being set from the factory anywhere from 2600 to 3200 rpm. This was likely an issue in the manufacturing process. There is a video on youtube where a user adjusts his rpm and his manual shows the recommended engine speed to be 2,950 to 3,100 rpm. In my case I adjusted mine to the highest recommended speed of 3,100.

https://www.youtube.com/watch?v=mxsIK00NN6E

Here is a link of the video. Be sure to consult your specific manual or Honda before making adjustments.

dfwchief · Jan 28, 2019

This new one I got doesn't have two holes in the linkage, just one. A person could make a 2nd hole or bend the end of the spring shorter. I guess I'll get a tach and see what I've got. I've always wondered if Honda put the two holes there because the first one met safety and emissions regulations, but they knew a lot of people would like to rev it up a bit for better performance.

In the good ol' days there would be a screw you could turn to make accurate adjustments.

trekgod3 · Jan 29, 2019

dfwchief said:
This new one I got doesn't have two holes in the linkage, just one. A person could make a 2nd hole or bend the end of the spring shorter. I guess I'll get a tach and see what I've got. I've always wondered if Honda put the two holes there because the first one met safety and emissions regulations, but they knew a lot of people would like to rev it up a bit for better performance.

In the good ol' days there would be a screw you could turn to make accurate adjustments.

I saw a video on YouTube where a guy uses pliers to physically bend the tab with the 2 holes in it instead of just moving the spring to the second hole.

https://youtu.be/7YrA3QEIFnE

trekgod3 · Feb 4, 2019

trekgod3 said:
I saw a video on YouTube where a guy uses pliers to physically bend the tab with the 2 holes in it instead of just moving the spring to the second hole.

https://youtu.be/7YrA3QEIFnE

Just ran it today for the 1st time with the tach. Start up rpm was 3010 and after warming up it was 3070

cruzenmike · Feb 4, 2019

trekgod3 said:
Just ran it today for the 1st time with the tach. Start up rpm was 3010 and after warming up it was 3070

It sounds like you are right on the money. How did she run and cut?

dfwchief · Feb 4, 2019

trekgod3 said:
Just ran it today for the 1st time with the tach. Start up rpm was 3010 and after warming up it was 3070

Thanks for measuring and posting. 3,000 seems to be the number for 21" mowers. Was that with the blade engaged and self-propel, or idle?

I've got a tach now, and some warm days here, so I'll see what mine reads. If it's right around 3,000, I'm not going to fiddle with it unless/until I have a chance to mow some tall and thick grass and it doesn't seem to perform.

I still don't have any grass to mow to check RPM while cutting.

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