Skip to main content
Collection, Preservation and Display of Old Lawn Mowers

Suffolk Punch 43DL - Not Starting

Hi folks,

Been a long time lurker on these forums since buying an old 35S and following your help to rebuild the carb. I've taken the plunge to be a full-fledged member.

I found a 43DL from '91 in my mother-in-laws shed. It is in need of a lot of love so starting to check it out and work through getting it going. It doesn't start but working through the reasons why and need some help. I'm new to a lot of this stuff so I haven't followed what I now realise is a process for fault finding. Here is what I have done (and not done) so far.

1. Changed spark plug but didn't check if there was a spark (whoops, beginners error)

2. Rebuilt and cleaned carb - all seems OK

3. Checked for spark by putting plug on a piece of metal - nothing

4. Assumed HT leads were OK because they looked OK. How do I check this?

5. Checked coil after removing flywheel - looks OK but need to see if you think that is the problem or there are some simpler things to check

I've added some pics below of the coil:

My next guess is to put everything back together and check HT lead and make sure that has good contact.

If that still fails I'll assume I need a new coil which I think is about £30?

Appreciate your help and sorry for the bad fault finding process. I'm a young'un and this is my first bit of tinkering on an engine I can see.



Geoff Beechey Tue, 30/06/2020

One of the first things to check when you don't have spark is the points, are they clean? Is the gap set correctly? If the answer to both is yes then you still have the condenser the coil and the HT lead, all can be checked with a multimeter, if you do not have one life becomes a little more difficult but you could use a battery and test globe to check continuity of the coil and the HT lead the condenser you can check by flashing across a battery and see if it charges but don't grab hold of the body and lead or you can get a not so nice surprise.


Chris G Tue, 30/06/2020

One of the first things to check when you don't have spark is the points,

If you can find them....

Thats a 2 or 3 polle electronic ignition

TomEllingham Tue, 30/06/2020

I think I'll put everything back together and get the multimeter going to see what I can work out. At least I know how to remove the flywheel now!

I also think the governor spring for the air-vane governor is missing. I'm assuming this wouldn't prevent it from running? Need to find another one of those if I can.

Chris G Tue, 30/06/2020

Tom, before you put it all back together, can you take some better pictures all round the coil, this may help with further advice.

wristpin Tue, 30/06/2020

Thats a 2 or 3 polle electronic ignition

May be but  a general view rather than a close up will be more helpful.  I think that you may have the late type points ignition with the condenser embedded within the coil.

If that is the case , give the points a good clean and reassemble the machine far enough for you to rotate the flywheel at cranking speed. Remove any plug cap or connector from the HT lead and hold it against an unpainted surface and see if a a spark jumps from the end when the engine is rotated - smartly.

If it is an “electronic “ coil remove it and have a look at the back. If the hard plastic case is separating from the potting material it is almost certainly new coil time .




Chris G Tue, 30/06/2020

That is a very useful doc from Wrispin and worth keeping. Fingers crossed!

Just to add, if it is the older 2 pole coil, these are much harder to get hold of and twice the price of the 3 pole last time I searched, but you could get lucky, the other issue being that the flywheel is specific to the coil so you can't put a 3 pole coil on a 2 pole flywheel. Hope that makes sense.

TomEllingham Fri, 03/07/2020

Thanks for all your help so far folks, really do appreciate. Tomorrow is Saturday and very much a tinkering day to see if I can get to the bottom with some of your helpful direction. One of you asked for some more photos of the points/coil. Hopefully, this helps - there appears to be a bit of bulging:

And last but not least a quick pic of the cap - looks OK but again I don't really know what I'm looking for. Far better with computers than petrol.

So my plan tomorrow is:

  • Clean up the points
  • Rebuild as far as getting the flywheel back on to check for voltage across HT lead/cap following the service bulletin from Wristpin (thank you!)

If no joy will assume it needs a new coil but will make sure I explore all avenues first before coming to that conclusion.

Also going to get it into my garage so it's nice and dry.


wristpin Fri, 03/07/2020

So my plan tomorrow is:

  • Clean up the points
  • Rebuild as far as getting the flywheel back on to check for voltage across HT lead/cap 

No points to clean !

Your first image appears to show separation between the coil shell and the potting material - not a good omen.

Chris G Sat, 04/07/2020

That does appear to be a 2 pole coil, had similar issues on a few machines, check this for info ->

Although the separation is not a good sign, I wonder how many working ones are still limping on with similar cracks, so still worth testing until you're definite.

Make sure that it is not earthing out the coil while you are searching for a spark.

Take not of this above comment also, to be sure it's not earthing out all the time, follow the thin black wire to the tang connector and unplug it for the spark test. The spark is not always easy to see unless you have a spark tester,