Richard C

OK, that explains the lack of communication from the club shop today. Thanks. However- why haven't you switched over to a 4g or 5g access point to enable communications support?

Hi Pete. Thanks for listing all the other factors that need checking, but the point of my post was that all of those having been dealt with, it was the incorrect needle seating that was critical to solving the issue. As you say, one might expect the adjustment screw to deal with this, but the fact is that it did not. Thus my point is that flush fitting of the needle to the air valve is crucial to correct operation, within an unknown few thou tolerance.

Not so much a question as an observation. My 13/60 has been running a bit rich for a few years, and I've not been able to weaken the mixture sufficiently with the adjustment screw. The carb has been apart many times, minor issues rectified, but still too rich. Today I took the needle out to check its straightness and wear, and saw that the shoulder was recessed slightly into its socket. Recessed not more than 1/32, probably more like 1/64. Reset the needle just like it says in the manuals (Doh!) EXACTLY flush with the air valve, and the problem is fixed. Can now set the mixture rich, lean, and just right. The problem must have arisen a few years ago when the need for a new float valve led me to renew the O rings and gaskets as well. As a second thought, exactly HOW critical is the needle seating to the carbs performance. If I had to move it 1/64, ie 15 thou to correct it, what tolerance is there? Third thought, if it works don't mess with it.

On my boat I use a buck-boost converter to provide a stable 5V to digital instrumentation and logging (rpi based). It works, and on the boat it copes with the sudden voltage drop caused by starting the engine after sailing. They are cheap from online sources, and the only drawback is possible RFI with audio equipment which can be dealt with in the usual ways. I am a bit concerned that a failure mode might put 12V on the output, so the addition of a zener diode and fuse might be appropriate. I'm not that concerned. In general, these switch-mode devices are far better at providing dc-dc conversion than 78xx series regulators, and neccesary for higher current loads,

I call these 'drat it' moments because they are above and beyond normal expletives. Fitted a new full width radiator a few years ago, found too late that the antifreeze tin was full of used engine oil. Drat.

I've been struggling with a very similar engine issue for most of this summer - symptoms indicating fuel starvation/vaporisation that disappear when the engine cools - no apparent problem when the engine is allowed to warm with the bonnet up. To cut a long story short, the fuel supply and carb were thoroughly overhauled but the problem persisted, so thoughts turned to ignition. Points and condenser replaced - no difference. Coil replaced - solved! I'd not heard of coils failing in this intermittent temperature related way before, there was no external evidence of it overheating, but it was definitely the culprit.