Thanks for all the suggestions , especially the last one.

The fault was due to the operating spring on the engine on/off switch
being undertensioned.

This meant that the switch was never fully operated , even when the
handle was pulled in the full on position.

I`ve taken it off and retensioned it and it now runs OK.

Thank goodness for that. I had visions of faulty electronics in the
magneto circuit so it certainly doesn`t pay to jump to conclusions.


I bought this version of lawnmower mainly because of the well known
reliability
etc. of the Honda engine

Thanks everyone.

Scott





The problem appears to be no spark ,( proven with neon-timing light)

I had a problem similar to this several years ago where the lawnmower
sometimes ran erratically and then finally falied to start. I proved
that it was due to no spark by taking out the spark plug, resting it on the
metal engine and looking for a spark when the starting cord was pulled..

I eventually traced the fault to the switch that controls the switching off of
the engine . This is connected via cable to the operating lever on the
handlebars that you have to hold ON when you are using the mower.( When
released , it earths the spark plug lead via this switch preventing firing at
the sparkplug and also applies a mechanical brake to the flywheel)

It was fairly easy to prove using a multimeter and if I remember correctly , it
was due to a sticking plunger that operated the microswitch. I cured it by
cleaning it up and lubricating it with a small squirt of WD40.

It`s ran OK ever since.

If that`s not the problem , then I would suspect the magneto , but magnetos are
usually very reliable.


If you want any further info then email me and I`ll see if I can help as I`m
still using the mower.

Vic




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