Suffolk eratic running

[paulw]

My 1996 14" Suffolk mower will not run at a constant speed.It will tick over and run flat out but I can't maintain a comfortable speed,I'm either too slow or I'm chasing it! The revs will increase at random.
It's been well maintained,had a replacement Delloto carb fitted and I've tried many different variations with the govenor arm and spring.Does it have some sort of internal speed control?
Any ideas welcome.
Thanks

 

[EngineMan]

My 1996 14" Suffolk mower will not run at a constant speed.It will tick over and run flat out but I can't maintain a comfortable speed,I'm either too slow or I'm chasing it! The revs will increase at random.
It's been well maintained,had a replacement Delloto carb fitted and I've tried many different variations with the govenor arm and spring.Does it have some sort of internal speed control?
Any ideas welcome.
Thanks

The link between carb and govenor is simple, a rod and spring, not sure what you mean by "I've tried many different variations with the govenor arm and spring" if you have tampered with the spring then I would replace it, make sure that the govenor is moving freely and fitted to the right hole on the carb, (see pic)

 

[bertsmobile1]

The throttle control stretches a spring which puts pressure on the govenor arm to try & make it open the throttle.
The govenor mechanism trys to close the throttle.
The faster the engine is turning the harder it tried to close the throttle.
At rest the govenor does not try to close the throttle.
Buy an inline spark tester and watch the spark.
If the tester is flashing out of sync with the revs of the engine you have an electrical problem
However I rather feel you will find this is a bad fuel problem so change your fuel and the plug.

Now Suffolk is a UK only brand so if you want anything other than generic information we will need the engine make & model number.

 

[paulw]

Engineman thanks, but my carb differs from the picture,does not have the "vane",#3 in diagram

 

[paulw]

Bertsmobile1 Thanks,any idea where I can find engine model and number on the machine?

 

[Catherine]

:welcome:

I'm going to move this thread over to our mower and equipment operation section in case you still need more advice.