When I took my T300 marine engine walkies to the Wessex SEC Annual Rally on Sunday last, it got all bothered & stopped on me. It then started again but stopped in that rather final, sulky way so well known to those of us that take up the care of Iron Charges. "I'm not going to run again until you have paid attention and looked at me properly."
So today I took the carb off (it had dripped occasionally) and found nothing. The float wasn't sunk, the needle valve shut off the flow of petrol that itself was stopped & goed by the tap in proper fashion. All the jets were clear.
Out with the plugs. No-one could call the spark startling, but it was present. Cleaning the points made no difference & a good light across them showed they were as clean as points could very well be. The plugs are dry, though & I thought it was running rich - certainly, it sounded like that, misfiring at low RPM. I peered into the plug'oles to see the combustion space - and discover long reach plug threads filled with long years of carbon. Had short reach plugs in it when I got it & I never thought anything about it.
Bugger.
I've got a plug tap somewhere, but could I find it? Naaa. The old trick of two saw cuts along the thread of a scrap plug did the trick & a pair of extended nose NGK's carry the dim spark out into the combustion chamber where it does the most good.
Choke, tickle, wind - BRRRM! How satisfying. Now it runs cleanly instead of going down on one at tick over as it always has done. Starts when hot & revs better. Another problem solved - back on the shelf with it!
Regards,
J. Kim Siddorn,