Oh carp. I've found farther trouble. I'm starting to fear this 'saw could become money pit. Not the saw's fault, but my lack of knowledge means I find a fault, buy a part and fix that fault then find the next fault, and so on. Oh well. The current fault I need opinions on how to proceed please. I got a new plug, took the old one out and happened to look at the plug port more carefully than I did the other day, and instantly spotted why the plug wasn't sealing before. The cylinder's plug port has been helicoiled and badly, the helicoil isn't right in and half a turn or so is sticking out the top of the threads in the cylinder, clearly preventing the plug's sealing washer from sealing. I'm embarrassed I didn't spot this before, and of course when I spot it today my dad is stood next to me so yep, I get that look from him and feel about 4 years old. So I'm now considering options ranging from:
1. my bodger dad's suggestion of just cut off the protruding bit of helicoil and tighten the plug down tight then cross my fingers; through
2. remove the helicoil and get another fitted; to
3. lets not faff with helicoils, let's take a look at a new piston and cylinder.
Now I suspect i know what you guys will say (3), but against that is the growing feeling that I'm out my depth and could fix this problem only to find another, so I want to fix this problem as cheaply as possible. As for cost, a quick google and a 52mm farmertec piston and cylinder kit comes up on ebay uk for just under £18, so parts aren't much more than a helicoil, but... hmm, is the helicoil easier? That depends how well the cylinder was threaded and if a new 'coil will go in or if it needs threading more deeply.
Lots of questions, not many answers, a bit of frustration and a big helping of extra embarrassment. Your comments are welcome, but please be nice, I'm feeling tender!