My first post. Hope this is the correct section to post this question
I have a Qualcast Suffolk Punch 35s electronic ignition lawn mower that as be cutting my lawns for a long time with no problems, just a service at regular intervals.
But the other day while trying to start the lawnmower there was a bang which I believe to have been a back fire? After then the mower would not start
I checked the fuel and the carburettor that was ok and the compression
But unable to produce a spark at the spark plug
Being a electrical engineer I check the cut off lead and the continuity of the ht lead all ok
Replaced the spark plug with a new one as there was no continuity on the centre electrode
Also replaced the electronic module 3 pole unit inside the flywheel with a new one
And still no spark also removed the spark plug cap which from the reading as a 10k ohm suppressor built-in and connected the lead directly to the plug
Inside the flywheel the electronic module is screwed in place with no adjustment and the flywheel with the magnets build in are keyed to the shaft so there is no adjustment
There is a small voltage at the plug but nowhere a voltage to create a spark also turned the motor over with a portable drill with the spark plug removed and the thread connected to the frame
Has anyone any suggestions what maybe wrong with the mower that’s stopping it sparking at the plug

On Mon, 25 Aug 2014 20:34:02 +0200, manuel
wrote:


My first post. Hope this is the correct section to post this question
I have a Qualcast Suffolk Punch 35s electronic ignition lawn mower that
as be cutting my lawns for a long time with no problems, just a service
at regular intervals.
But the other day while trying to start the lawnmower there was a bang
which I believe to have been a back fire? After then the mower would not
start
I checked the fuel and the carburettor that was ok and the compression

But unable to produce a spark at the spark plug
Being a electrical engineer I check the cut off lead and the continuity
of the ht lead all ok
Replaced the spark plug with a new one as there was no continuity on the
centre electrode
Also replaced the electronic module 3 pole unit inside the flywheel with
a new one
And still no spark also removed the spark plug cap which from the
reading as a 10k ohm suppressor built-in and connected the lead
directly to the plug
Inside the flywheel the electronic module is screwed in place with no
adjustment and the flywheel with the magnets build in are keyed to the
shaft so there is no adjustment
There is a small voltage at the plug but nowhere a voltage to create a
spark also turned the motor over with a portable drill with the spark
plug removed and the thread connected to the frame
Has anyone any suggestions what maybe wrong with the mower that’s
stopping it sparking at the plug

How old is this mower and when was it last professionally tuned up...
could be many reasons why it won't run... needs to be tested by a
professional. You installed a new spark plug, you might want to
replace the ignition wire too, then if it won't run it's time to pay
the shop. I recently had a similar problem with a Sears Craftsman
push mower I'd been using for 18 years... I decided it would be
foolish to pay more to have it repaired than it was worth... I long
ago got my money's worth. I had tinkered with it for a while and
finally put it out at the curb and treated myself to a brand new push
mower. A professional tune up would have cost about half what I paid
for the new mower, and I'd still have an 18 year old mower that at any
minute something else could go wrong. I love my new mower, it's
quieter, pushes easier, and cuts better, also starts on the first pull
every time... the Honda engine is wonderful... I think you can buy
this in the UK:
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

[QUOTE=Thank you for your response


When replacing the electronic module it as all new cables attached
So all the HT and the trip wire have been replaced
The mower is serviced at regular intervals
And is only 10 to 12 years old

manuel wrote:[i]

[quote=Thank you for your response

When replacing the electronic module it as all new cables attached
So all the HT and the trip wire have been replaced
The mower is serviced at regular intervals
And is only 10 to 12 years old[/i]

10-12 years is pretty much at the end of a mower's life. I would
contact the shop that's been doing that regular servicing and request
an estimate for a tune up and decide if the cost is worth the
investment for so old a mower. It might be money better spent towards
a new mower... I don't like to put good money after bad... in my
experience right after paying to repair something old it dies
altogether. I like to have a mower that I can count on to work when I
need it, were it me I'd buy a new mower and perhaps keep the old one
to tinker with if you've a mind to do that, I wouldn't waste my time,
energy, and resources. That's why I put my old mower out at the road,
wasn't ten minutes a neighbor's teenaged son knocked on my door to ask
about what was wrong with it, I told him I didn't know but he's
welcome to it for free, I only asked if he'd let me know if he got it
running. That was last summer, he still hasn't done much with it
except take it all apart. Push mowers don't cost very much, if you
spend $300 and it lasts ten years it cost $30 a year or about $1 each
mowing for the growing season... petrol costs more and old mowers
waste fuel. Good luck.