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How much hp for a tow behind mower?

11K views 11 replies 10 participants last post by  biker 
#1 ·
How much hp would I need for a tow behind mower? I have a extra lawnmower engine at about 5 hp. Would it be possible to hook it up to a extra lawndeck 38-40 inch wide? Would it cut tall grass well?
I know many small 38-40 inch mowers have 10-15hp engines. But they have a extra load to pull(person, and the rest of the tractor). So would a small engine be a bare minimum?

I was looking at something like this.

http://www.mytractorforum.com/showthread.php?t=180722

or this

http://www.mytractorforum.com/showpost.php?p=1380159&postcount=7

Thanks for the feedback!

7
 
#2 ·
I'd say you'll be a bit short of horsepower for cutting tall (field) grass at speed. An 8hp Gravely walk behind (all gear drive, minimal loss) can easily bog out on high grass with a 40" deck in high gear. In low gear with a 30" deck, they are pretty good. Remember that small mowers are typically used for mowing LAWNS, not high grass. Deck throughput clearing the grass end up sucking up a good bit of horsepower. I think that what you are proposing would probably work OK for lawn mowing, but will bog down in high grass.
 
#3 ·
I have rebuilt my friends Haban 42 inch tow behind twice now. First time replaced the 8 HP Briggs (lost a valve seat) with an 11 HP Briggs engine that also last a valve seat. The second time went to a 13.5 HP Briggs OHV. More HP is better. 5 HP is for a 18 to 22 inch deck. Most tow behinds are much wider. Roger
 
#4 ·
Minimum of 2 hp per foot of width for a manicured lawn. More for mulching or bagging.

Minimum of 4 hp per foot of width for tall grass.

As has been stated, more horses eat more grass!

You're a wee bit light in the horsepower department for that mower.
 
#6 ·
Minimum of 2 hp per foot of width for a manicured lawn. More for mulching or bagging.

Minimum of 4 hp per foot of width for tall grass.

As has been stated, more horses eat more grass!

You're a wee bit light in the horsepower department for that mower.

This tractor is only 4 hp. I've mowed grass over the hood with no problem. I've pulled full size pickups with no problems.
 

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#5 ·
Thanks for the feedback!!! Really good info here. Now I just have to find out how many inches are a foot.... ;)

Too bad, I was hoping for a nice project next winter. Well maybe I can hunt down another lawnmower engine => one engine per spindle! :D


7
 
#7 ·
Yes you can use a 3 1/2 HP 20" or 22" push mower. I have mowed more then enough acres that way 60 years ago. It's how fast you want to mow. My guess is with a pull behind you want to cover a lot of area fast. I would say 10 to 12 HP minimum and more is better. As I remember it you went very slow in heavy grass and real heavy grass there was stop and back up to keep from killing the engine.
 
#10 ·
The 5hp tractor to your left runs a 28" deck, and a 27" snowblower.

Simplicity had a 6hp RER that ran a 32" deck.

The Simplicity 700 ran either a 36", OR the 42" deck with a 7hp 19D Briggs engine.

I would say that you might be working the 5hp engine a little hard if you end up cutting thick grass. You might find yourself with very slow ground speed if the engine is working too hard.
 
#12 ·
The onew behind the Ford looks nice. I don't why you cant do what you want to do. All you can do is try it.
 
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