Qualcast Suffolk Punch 35s Problem

[WeFixIt]

Something's are being looked at a little to deeply I think!!

 

If a engine this size has a correctly working ignition system it will produce a good spark on any of the common lawnmower spark plugs resistor or not

If like stated earthing stop lead has been disconnected the flywheel key is good and magnets are good!

 

Two things remain!

The gap between magnets and ht coil are to big! Easy way to reset this - turn the flywheel so the magnet is

Inline with the coil place a folded price of paper between the two slacken the coil bolts magnets will pull the coil down on to the paper relighted bolts and turn flywheel to remove paper

 

If this doesn't work then the coil needs to be replaced.

 

Back fire could of been cause by fuel passing through the engine and igniting in the exhaust due to intermittent spark common on ignition coils before they give up.!!

 

 

 

 

 

Is it a chipper, is it a mower or another broken stump grinder who cares we'll fix it!

[cornish wood burner]

Adding to Wefixits post regarding checking the coil gap. Is the old and new coil mechanicallly the same regarding mounting holes. Have you checked what resistance there is between the kill wire and frame. Internal short would kill your spark. Megger the ht lead possibly.

 

As an aside I don't think I would risk my volt meter on a ht circuit.

[manuel]

both wefixit and Cornish wood burner are right in there post

 

but when the flywheel is on it total covers the module and in not accessible at all the module contains the iron core coil and the electronics is encapsulated in black resin with a steel bracket with screw holes in which can not be adjusted and the magnets are embedded in the inside of the flywheel

 

I have replaced the module twice which automatically replaces the kill wire and HT lead

have replaced the spark plug

 

at this very moment are disassembling the mower for the 5 time

 

it seem a simply problem for me as a Electrical Engineer

 

will check it again

[cornish wood burner]

Have you checked if the mounting holes are exactly the same relative to the flywheel edge of the core on the original and replacement modules?

Are the replacements new or secondhand?

What is the resistance between the kill wire and the coil core?

[mikerecike]

Is your recoil pulling technique as effective as ever? Somebody once swore to me his mower wouldn't start - the issue was..HE couldn't start his mower - couldn't get a decent spin and spark. I know this is off the diagnostic trail but what's the multimeter telling you about your biceps? 👍

[manuel]

Hi Cornish wood burner

 

the part is a genuine part F016L34244

 

while turning it over with my arm I notice that fumes were going out of the side of the engine

 

and assume the back fire had blown a small amount of cylinder gasket out

 

so have taken the head off the engine and waiting for a new gasket to arrive

 

will update ASAP

[manuel]

Update

 

Success it working replaced the head gasket

 

spoke to a guy who repairs Suffolk lawn mowers

 

he says the on a electronic ignition if very unlikely to see a spark until it's turning over at the normal idling speed

 

tested with the old electronic module in and it did not start

 

therefore the electronic ignition needed replacing and the spark plug failed and the head gasket needed replacing

 

 

Thanks to all that kindly posted with constructed advice

 

Time to cut the lawns ?