GardenBanter.co.uk

GardenBanter.co.uk (https://www.gardenbanter.co.uk/)
-   Lawns (https://www.gardenbanter.co.uk/lawns/)
-   -   Converting lawn mower to manual throttle? (https://www.gardenbanter.co.uk/lawns/184623-converting-lawn-mower-manual-throttle.html)

stoneattic 10-06-2009 05:06 AM

Converting lawn mower to manual throttle?
 
I have a cheap MTD mower with a 5hp B&S engine. The "automatic"
throttle lost a spring and the plastic piece that appears to control the
engine speed (the vertical piece in this pic:
http://www.kichline.com/chuck/fixit/...s4hpspring.jpg)
is broken so I converted it to a manual throttle cable. I connected the
cable to the piece that is connected to the plastic piece in the above
pic via a rod with a loop in it. (Hopefully the pic and description
make sense).
The thing is that if I'm sitting still the cable controls the RPMs as
expected but as I move the mower around RPMs fluctuate even if I'm not
cutting anything. I except the RPMs to drop when there's a load from
cutting but it seems random and will surge and drop.

Any thoughts? Is there something else that controls engine speed that I
haven't found on this engine?

thanks in advance!

ferrarif360cs 14-06-2009 12:10 PM

Quote:

Originally Posted by stoneattic (Post 850250)
I have a cheap MTD mower with a 5hp B&S engine. The "automatic"
throttle lost a spring and the plastic piece that appears to control the
engine speed (the vertical piece in this pic:
http://www.kichline.com/chuck/fixit/...s4hpspring.jpg)
is broken so I converted it to a manual throttle cable. I connected the
cable to the piece that is connected to the plastic piece in the above
pic via a rod with a loop in it. (Hopefully the pic and description
make sense).
The thing is that if I'm sitting still the cable controls the RPMs as
expected but as I move the mower around RPMs fluctuate even if I'm not
cutting anything. I except the RPMs to drop when there's a load from
cutting but it seems random and will surge and drop.

Any thoughts? Is there something else that controls engine speed that I
haven't found on this engine?

thanks in advance!

If I remember rightly there is a small air vane that sits in the air stream from the cooling fins on the flywheel. This keeps the engine at a reasonable constant speed setting, I suppose it is feasible this vane is damaged or something. The "throttle" control you mention is connected to that spring via the linkage. It tensions the spring and causes the air vane to be less effective in slowing the engine down.
I hope I explained this ok.

Bob F 24-06-2009 09:23 AM

Converting lawn mower to manual throttle?
 
stoneattic wrote:
I have a cheap MTD mower with a 5hp B&S engine. The "automatic"
throttle lost a spring and the plastic piece that appears to control
the engine speed (the vertical piece in this pic:
http://www.kichline.com/chuck/fixit/...s4hpspring.jpg)
is broken so I converted it to a manual throttle cable. I connected
the cable to the piece that is connected to the plastic piece in the
above pic via a rod with a loop in it. (Hopefully the pic and
description make sense).
The thing is that if I'm sitting still the cable controls the RPMs as
expected but as I move the mower around RPMs fluctuate even if I'm not
cutting anything. I except the RPMs to drop when there's a load from
cutting but it seems random and will surge and drop.

Any thoughts? Is there something else that controls engine speed
that I haven't found on this engine?

thanks in advance!


It looks to me like the vertical piece is the govenor, that adjusts the throttle
according to load. Missing that, the speed will be very unstable.



mm[_1_] 07-09-2009 03:52 AM

Converting lawn mower to manual throttle?
 
On Tue, 09 Jun 2009 23:06:17 -0400, stoneattic
wrote:

I have a cheap MTD mower with a 5hp B&S engine. The "automatic"
throttle lost a spring and the plastic piece that appears to control the
engine speed (the vertical piece in this pic:
http://www.kichline.com/chuck/fixit/...s4hpspring.jpg)
is broken so I converted it to a manual throttle cable. I connected the
cable to the piece that is connected to the plastic piece in the above
pic via a rod with a loop in it. (Hopefully the pic and description
make sense).
The thing is that if I'm sitting still the cable controls the RPMs as
expected but as I move the mower around RPMs fluctuate even if I'm not
cutting anything. I except the RPMs to drop when there's a load from
cutting but it seems random and will surge and drop.

Any thoughts? Is there something else that controls engine speed that I
haven't found on this engine?

I'm late but you still need the automatic part, even with a manual
throttle. They all have it. Otherwise it will stall quicker than you
can ajust the throttle.
thanks in advance!




All times are GMT +1. The time now is 10:11 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
GardenBanter