My first post, question about throttle speed

1ManCrew

LawnSite Member
Location
South Florida
The throttle cable recently snapped on my Scag and I had to simply pull the throttle lever near the engine all the way to where the Kawasaki factory set-screw was set. The mower is raging with power now, goes about 2mph faster, with tons of cutting power. I don't have an RPM gauge..... is this throttle stunt going to damage my mower? Or am I now merely running it at the full 18 HP it was designed for? Thanks for your help.
 

AlohaMowing

LawnSite Senior Member
Location
Hilo, HI
Until you can get a tach to check the rpm, and until you can replace the cable, I'd suggest you not "pull the throttle lever near the engine all the way to where the Kawasaki factory set-screw was set" but rather rely on your ears to pull the lever to the point the engine rpms sound like before. While running the engine faster than necessary probably is not going to cause a problem, there would be some additional wear if this goes on long and the engine would probably run hotter, and fuel consumption can increase greatly at higher rpms.
 

fastline

LawnSite Member
The throttle cable should not be dictating the RPMs your engine runs at full throttle. That is controlled by the governor. Entirely possible that you are finally getting the throttle moved to the real full throttle though but as suggested, I do recommend a quick check with a tach.

I use a very basic and cheap optical tach for stuff like this. I put a piece of aluminum tape on anything connected to the crank and use the optical tach to read that. Very simple and 100s of uses.
 

flintknapper

LawnSite Senior Member
What engine do you have on it?

Some of the 'Kaws' can benefit from upgrades *especially the FH series*.

For instance its possible to increase the HP of an FH601V *19hp* to 23hp or even 25hp with a simple throttle shaft change and governor adjustment. *Oil cooler added for the 25hp mod*.
 
OP
1

1ManCrew

LawnSite Member
Location
South Florida
What engine do you have on it?

Some of the 'Kaws' can benefit from upgrades *especially the FH series*.

For instance its possible to increase the HP of an FH601V *19hp* to 23hp or even 25hp with a simple throttle shaft change and governor adjustment. *Oil cooler added for the 25hp mod*.
FR600V
 

flintknapper

LawnSite Senior Member
When you get your tach set your high speed at 3600 rpm.

One thing you might look at (engine off) is when the throttle lever is fully 'thrown' 'WOT' Wide Open Throttle, check to see the position of the butterflies on the carb throttle shaft. IF they are not fully open *Horizontal*....then there is still some performance gains to be had. But do so at your own risk.

Kawasaki on several of its Engine series uses the carb setting to control engine HP.

Both the FH series and your FR series engine do this. There are engines within those series that have identical displacement, bore and stroke. In most cases identical carb jetting and only by opening the butterflies more... do they control the hp output, along with the attendant governor adjustment.

In any case....you don't want to exceed the mfg. recommended high speed setting of 3600 rpm, which I suspect is what you are doing....OR it wasn't running at the that MAX rpm before and now is.

Do..... take the time to make sure your engine is properly adjusted so you get full performance. A small tweak here or there can make a big difference as you've discovered.
 

Freaky Fido

LawnSite Bronze Member
Location
Northeast USA
Sounds like your throttle cable wasn't adjusted properly. If it just has a clamp that holds the casing, those can slip because you can't crank them too tight or you'll mash the housing. On backpack blowers, especially those with tube throttles, it's very common for the cable to stretch and for the blower to lose power. You don't realize it because it happens slowly over time. The one on my Husqvarna 580BTS stretched so much that I had to bend the bracket to get it to full throttle.
 

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