# Teach me about HP



## Jace3809 (Mar 31, 2006)

While I'm mowing all day, every day, it leaves you lot's of time to think. Well, today I was thinking about engine sizes. While I was putt'n on my 12.5 I was thinking about some threads I read here the past few days. I'm trying to speed my machine up, and have been contemplating an engine swap. But tell me... Does a bigger HP engine equal more RPM's? The other day I asked if I could adjust the governor to increase RPM's, and I was advised not to. Seems to me that a bigger engine would increase torque but not RPM's, and RPM's = speed. So I ask you guys, am I understanding this right or am I missing something. What is a bigger engine going to do for me? :freak:


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## bugman (Aug 12, 2004)

Ok, a bigger more powerful engine will still run at the same 3600 rpm as your 12.5, but take this.... say one 12.5 powered 42 inch riding mower... and one 42 inch 18.5 powered mower... the 12.5 can cut the grass at the same low level as the 18.5, BUT if your going to fast the engine will want to bog down, while the 18.5 can go a much higher speed cutting the same grass. This is why you don't see small hp engines on zero turn commercial riders. You can basically notice this between a 3.5hp pushmower, and say a 7hp pushmower. The 7hp will have a bigger deck, maybe a self propelled system, and go through the grass faster and easier. Atleast I do notice the difference between my 3.5hp briggs 20 inch, compared to my 6hp quantum 22 inch, and my 12 horse briggs compared to my 18.5 intek. The 12 horse has a 39 inch cut, while the 18.5 has a 42.


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## bsman (Jan 22, 2006)

I think of it as a fire... a small fireplace you can put wood in, and get a little heat.....but a bigger fireplace you are able to add more wood and get more heat......if that's helps.


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