[SimonIG10]

Had a weird problem today with a Qualcast rotavator. It started fine and I rotavated for about 20 mins. I then stopped it, moved it and it refused to start. I had limited tools but I removed the plug and it appeared to have no spark when rested against the engine. I then left it for a couple of hours while I resorted to manual digging. Prior to leaving I tried it again and it started straight away. Ive also tried it again at home and again it started fine. is it likely to be a plug issue or maybe coil problem? When I use it again I will take the plug from my mower and a spark tester. It did stop quite suddenly the other day and assumed it was out of fuel. I left it for a while before refilling and it then ran okay (although wasnt used for any work). Maybe this was the same issue.

[Kleftiwallah]

Just a thought, could it be the fuel evaporating with the heat (fuel flow problem)?

Cheers, Tony.

[SimonIG10]

I don’t think so. It looked like there was no spark.

[Kleftiwallah]

Dip the plug into the fuel tank, light it!  Wait for the flames to die down, insert plug and try again.

Cheers,  Tony.

[SimonIG10]

Today it ran for about 20 mins then suddenly died. Verified no spark present. Let it cool for an hour or so then restarted okay but again only ran for a short while then died again. This engine was heavily soaked in a flood during the Winter resulting in a complete strip down to remove all the emulsified oil. I wonder if water got in the magneto coil, it’s definitely not the plug as fitted a spare and no joy. Can they fail when hot?

[R Tallentire]

You don't specify what engine the Qualcast has. Briggs & Stratton magneto coils have a habit of doing this trick when on the way out. Engines with points can do this too, the points seem to work for the first few min after a lay up, then fir up. However they don't usually re-start again until you have cleaned them up. If the choke is stuck on, engines run while cold but won't when hot. However the plug is obviously black and sooty when this happens.

[jezza]

Hello as R Talkentine says it's probably the coil or hightension lead that's  broken or breaking down ive just replaced a coil pack on a Briggs engine on a Hayter Harrier  try Briggs bits for a new coil give model type and code it'll show the parts  jezza

[SimonIG10]

Thanks for the advice....Its an SV150 engine (looks like a B&S clone). Ive just ordered a new coil as you guys have confirmed what I was thinking. Hopefully this will sort it as it is a nice little rotavator.

[Kleftiwallah]

Being a restorer and rider of vintage British motorcycles I've come across this problem,

Laqueritis  There are a few magneto magicians still around.  I can let you have an address if wanted?

Cheers,Tony.