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Collection, Preservation and Display of Old Lawn Mowers

How do you stop it ?

Hi one and all,

I've recently acquired a QualCast 35DL and unlike a lot of other posters I can start it easily but it doesn't stop.

On the handlebar there is the throttle control that all works just fine and it says 'stop' on there. However it doesn't stop the engine. I assumed that the cable, in the stop position, earths out the ignition and then that would cause the engine to cease and so I adjusted the cable so that contact was made (on top of the carb) but that doesn't seem to be the answer.

So, my question is what does stop the engine - just want to make sure I'm not barking up the wrong tree.

sidevalve@44 Fri, 11/05/2018

I am assuming your Qualcast is similar to my ATCO with a Suffolk A98 engine with Zenith carb. If the lever on the carb is making contact with the earth stop and the engine won't stop then it would appear that the earth cable has a break in it somewhere. Firstly, is the lever actually making contact ?  I have to give mine a helping hand for the last fraction of a millimetre !  If that doesn't work, then check the wire back to see if there are any obvious breaks, and make sure the spade connecter is making good contact with the terminal. If that's OK, you may have to remove the flywheel to see if it is connected OK to the coil or if there is any obvious damage. 

CaptainKid Sat, 12/05/2018

Thanks for your reply. I was pleased to see that the lever wasn't making contact (at the carb end) as I then thought it would be easily sorted.

I did help it assuming that this was how it would 'short' out the engine - but it didn't stop.

I just wanted to make sure that this was the intended way to turn it off which you have confirmed.

I can now follow through your other suggestions to see what's amis, again many thanks.

wristpin Sat, 12/05/2018

Having discovered that the “switch” is ok you have now to investigate the other of the wire. The A98 May have electronic ignition or if a early version a points ignition system with the condenser encapsulated in the coil. Either way that cut out or kill wire should be connected to the low tension side of the coil, either directly or via the contact breaker points. 

You may be able to observe that it is physically connected through the window in the flywheel that is provided for cleaning and adjusting the points but if your engine has the later electronic system, it will be necessary to  remove  the flywheel. If you have multimeter  it may pay to make a couple of continuity checks before  undertaking any dismantling.

hillsider Sun, 13/05/2018

Just to prove that there is not an earthing problem with the throttle lever have you tried shorting the terminal directly to earth using a screwdriver or a short length of wire?

Following a valid comment from a fellow forum member I should clarify that the throttle lever that I am referring to is the one on the carb body, my thinking is that you need to eliminate the possibility of that lever not earthing due to dirt or dried grease.

CaptainKid Sun, 13/05/2018

Plenty to try then - once again thanks all for the input.

I can't 'play' until Wednesday now so will update then . . . 

CaptainKid Wed, 16/05/2018

Once again thanks for all the input. And the winner is . . . 

" . . . my thinking is that you need to eliminate the possibility of that lever not earthing due to dirt or dried grease."

Turns out that although it looked like it was touching it wasn't. Used brake cleaner liberally over the carb (and cable) and all is well.

hillsider Wed, 16/05/2018

Thanks for updating us on your progress, it would be a good idea to apply some fresh oil to the cable though if you have note done so already just keep things moving smoothly.

Note for Admin: -

Please can you delete the blank postings for me there was a malfunction this morning that resulted in blank postings.