Board logo

Turbocharged Honda (lawnmower)
v8kid - 26/10/16 at 08:50 PM

no it's not another go faster USA lawnmower blog but a seriously important point (for graasscutters).
I've got a 650cc twin lawnmower and cut a sloping 6 acre lawn, it's too bloody slow! Going uphill I have to slow down to leave enough power to the cutting blades I reckon if I had another 5 hp I'd Fi is at least an hour sooner.
So how to do it?
The ignition is magneto and the fuel is a rudimentary carb. Fuel consumption is not an issue as I can cut the whole field on a tank full. The engine has a vertical crank and I'm willing to spend 1k.

What do I do?

If the time spent exceeds 1 years time saving it's a bummer as I have a life (of sorts)

The existing mower has a 1.2m cut and to upgrade to a significantly wider cut is def not locost.

Unusually I can't decide looking for inspiration

Cheers!


ste - 26/10/16 at 10:34 PM

Nitrous Oxide?


ettore bugatti - 26/10/16 at 10:39 PM

Already taken the governor off?

But youtube offers all the options you want to look into.


mark chandler - 26/10/16 at 10:55 PM

Sell it, put the money towards some gang mowers and a little Ferguson tractor.


russbost - 27/10/16 at 08:04 AM

could you not simply add a 2nd engine linking the 2 with a drive belt - something like this unit maybe (I'm assuming what you have has a vertical shaft drive?)

6.5hp engine electric start petrol vertical straight shaft 196cc 4-stroke 2L

Alternatively simply a larger or more powerful version of what you already have - you don't say how many HP it has at the moment, if it was horizontal drive I'd say stick a motorcycle engine on it

You already have 650cc, would higher compression, gas flowing & a larger carb not give you another 5hp?


mark chandler - 27/10/16 at 08:58 AM

You could of course go left to right rather than up and down, that's free!

Bigger carb may provide more HP, will it add a lot of torque though... If you can find a small turbo, feed it oil (has your motor got an oil pump you can access) then this does sound promising.

Older mowers had horizontal engines as that's all they made with a v belt twisting 90 degrees, will your drive allow this?

I w our still go TVO fergie, more fun , my mate had a few acres and dragged a mower gang around behind a landrover....

[Edited on 27/10/16 by mark chandler]


motorcycle_mayhem - 27/10/16 at 04:12 PM

You need a MF35 and a cutter deck.

In a previous life, this is what I used when I had some real estate. The MF35 is a lovely thing.


Irony - 27/10/16 at 05:12 PM

quote:
Originally posted by mark chandler
You could of course go left to right rather than up and down, that's free!

Haha, the OP is probably kicking himself.

[Edited on 27/10/16 by mark chandler]


Jon Ison - 27/10/16 at 05:28 PM

Buy a horse


joneh - 27/10/16 at 06:40 PM

Lose weight? Sharpen the blade? Check tyre pressure? Check air filter is clear?

Free to do and could make some gains.


morcus - 27/10/16 at 09:21 PM

Geese


sdh2903 - 27/10/16 at 09:26 PM

Horses destroy fields, you need a small flock of sheep. Give em a bit of a haircut everynow and then and you'll get some good fresh lamb in the spring.


owelly - 28/10/16 at 04:16 AM

Mount another engine on the cutter deck and tow it alongside the tractor. That leaves the tractor engine to do its thing whilst the mower engine can run flat out.


nick205 - 28/10/16 at 08:08 AM

quote:
Originally posted by Jon Ison
Buy a horse





Quality - let nature do the work for you.

With a father selling garden machinery for a living my suggestion would be to take it easy and invest in a lawn tractor with collector. Much more fun!


v8kid - 10/2/17 at 02:50 PM

OK tried almost all of those suggestions - SUCESSFULLY!

With hydrostatic transmission the highest gear ratio is fixed so logically I have to increase revs - first suggestion was to remove governor however her indoors drives it sometimes

A bit more research showed that these engines get valve float above 4k revs so some experimentation with governor springs increased the no load revs from 2700rpm to 3600rpm. So far so good.

However additional revs does not necessarily mean sufficient power to pull revs so I changed the mulching blades to straight cutting blades which absorb substantially less power. Ditching the grassbox and making up a polycarbonate grass ejector chute dropped 50lb weight.

Result? I now cut the whole field in a quarter of the time that I used to - the wee sonsie thing even does power slides in the muddy bits going downhill The extra revs on the cutter blades seems to cut rushes easier and it does not slow down when going through a patch of them now. However the noise of the twin rotor blades is scary - needs ear defenders and I'm very happy to have a solid steel deck in case the blades come loose - as has happened before!!! ( witness the gauges out of the deck).

I think I have just enough room to go up a tiny bit in tyre diameter at the back and that's it for the mechanical mods. Total cost £60 for new blades - the old ones had been sharpened umpteen times so say half that could be allocated to wear and tear - £30 cost!!.

As for cutting patterns you are all wrong the fastest way is cutting in a circular pattern and ensuring going downhill at boggy bits otherwise it gets well and truly stuck ( perhaps paddle type rear wheels is a solution?).

Ta for all the replies after my research I now know more about GX620 engines than most people really should

Cheers!

PS Horses make a Bl00dy mess of fields - never again!

[Edited on 10-2-17 by v8kid]

[Edited on 10-2-17 by v8kid]