The Old Lawnmower Club
Collection, Preservation and Display of Old Lawn Mowers
X

Suffolk Pinch running problem

Enter a word or two to search the forum section and click the Search Forum button.
PeterRake Fri, 28/10/2016

I'm having trouble with an old Suffolk Punch 35S approx. 25 yrs old.  I've renewed filters and plug, cleaned out Dellorto carb.  but it still will not start.  Petrol is flowing freely into the carb.  However, I can get it to start for approx. 1 second if I put some petrol directly into spark plug hole and (obviously) replace the plug.

I'd appreciate help.  I've got a modern ?? Petrol rotary mower but I don't like being beaten (plus the Punch gives a better cut in my opinion).

Forums

wristpin Fri, 28/10/2016

As you say, a cylinder mower mows the lawn while a rotary just cuts the grass!

Sounds as though despite your efforts there is still a blockage somewhere in the carb. Did your cleaning process include removing the main jet / emulsion tube that screws up through the centre of the float chamber above where the bowl nut screws in. If you have not removed it , don't rush to do so until you have obtained / modified a screwdriver with a parallel squared off end to engage fully  in the jet slot and not damage the threads in the centre stack while doing so.

If you've already cleaned that jet and are sure that all its fine drillings are clear it is possible that some of the inaccessible small passages in the carb body are contaminated with stale fuel or fine debris. You can try using an aerosol of carb cleaner to squirt into every visible orifice but a session in an ultrasonic cleaning tank is more likely to succeed.