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Collection, Preservation and Display of Old Lawn Mowers

Suffolk punch 43s L23888 starting procedure


new to this forum

I have been given the above mower as a non runner.

Given it a bit of TLC, sorting fuel leaks, leaking tap pet chest cover, rusted recoil starter spring etc.

It has a spark (although the plug gap looks to be only .6mm) but the spark is not as bright as the one I remember on my old mini! On the casing it says electronic ignition. Plug is ngkB2-LM.

it has run for a few seconds but that is it. It will not start!

i have stripped the carb as it had  a sticky float - fuel running out of the air filter but the carb itself looks pretty clean.

The carb is the  delorto with the two position choke. The governor is the vane type and the kill switch is open as soon as the throttle lever moves off the stop setting.

If I put it on full choke and pull it over with throttle on idle, after 3 or 4 pulls, the plug is wet with fuel. Seems too much to me, but not worked on mower engines before!

Cannot find a manual online, so does anyone know what is the procedure re choke / 1/2 choke and throttle setting or make any other suggestions?

Any suggestions most welcome!




wristpin Thu, 26/05/2016

First check that moving the throttle control off stop is actually taking the kill switch on the throttle plate ,adjacent to the carb, off kill and that you do have a spark.

If you have a spark I  suggest two thirds throttle and full choke . If it then fires but doesn't pick up, go to half choke and hopefully it will pitch up and run. Too much pulling on full choke can lead to flooding.

JohnWillmott Sun, 29/05/2016

Finally got it fired up on half choke and throttle a bit open and it run ok but low speed was a no go.

had to turn the only mixture screw on the delorto carb in quite a bit and managed to get it running at a speed where clutch was just biting and blades stopping and starting.

going to get some carb cleaner to give the carb another overhaul.

is there a default setting on this mixture screw eg fully in then X turns out?

wristpin Sun, 29/05/2016

Start with one turn out the when fully warmed up and without any choke tweak it for smooth running and no hesitation when the throttle is opened.

When stripping and cleaning the carb make sure that you have a good fitting screwdriver for the main jet / emulsion tube so as not to damage it and make eventual extraction a far more difficult and expensive operation. Aso don't forget to thoroughly clean out the well in the bowl nut.


JohnWillmott Mon, 30/05/2016

Was just wondering if the valves may need lapping in - leaky valves cause more trouble at low speed?

Could really do with a workshop manual as not sure what I need to be taking off to get at what!


any ideas where I could get one?


wristpin Mon, 30/05/2016

A valve job certainly won't be time wasted . Don't think that there was ever a workshop manual as such  but with the engine' s Tecumseh ancestry there is plenty of info available from that direction. 

A valve job only involves removing the head and valve chest cover but taking the carb and manifold off will give better access.

JohnWillmott Sat, 04/06/2016

Thanks for that.

Will have a look and let you know



hortimech Sat, 04/06/2016

No, the valves are retained by small pins or slotted holes in the lower spring retainer.

There was a special tool to compress the spring,  but you can use a couple of screwdrivers instead as levers. Lever the spring upwards, if you can see a pin, pull it out with pair of longnose pliers. if it is the later type, find where the slot is and turn the lower spring retainer until the slot is towards the rear of the valve chest, now lever the retainer and spring upwards and try to pull the retainer outwards, if successful it should then allow you to remove the valve. Repeat for the other valve.

As always, it is easier to show someone how to do this, than describe how to do it. Hopefully you get the idea, try and see how you go on, any problems just ask.

Oh, and there was an Aspera workshop manual, but good luck in finding one. Whilst the engines were made under licence from Tecumseh, there are a lot of differences between the two.



JohnWillmott Sat, 04/06/2016

Thanks for the reply.


made 2 plastic wedges to lift the spring - it is the pin type.


Got them out and there was a leak on the inlet valve - the was a streak of soot on the back of the valve where it had been blowing past the valve seat.

will try to start it tomorrow!