I bought a 14xx as a first loco from a well known retailer. Tried it on the club track twice and couldn't get it to steam properly. Apart from issues with the injector and axle pump the thing does not have a petticoat pipe fitted. I know there are known issues with these locos, hence the articles in ME last year, but I would have thought not having a petticoat pipe could be considered a big issue. An I correct thinking this.
As the saying goes - 'been there, done that!' Your 14XX sounds much the same as mine when I first got it! I ended up going down the same route that you have in mind - and it worked! I replaced the injector with one from Steam Fittings, made sure the crosshead pump was correctly aligned (to reduce wear on the seal - but I seldom use it as the injector is 100% reliable), and fitted a petticoat pipe to the chimney. It has now done 5 years sterling work, and will still haul 8 passengers and a guard with reasonable ease (getting under way can be a bit tricky, though). The only other mods I carried out was to remake the slide valves so that they were thick enough not to fall away from the ports when stationary, and to stiffen the springs on the trailing axle - previously, it would 'nod it's head' as if too much weight was being carried on the centre axle. The change in weight distribution also overcame a tendancy to derail the leading axle on rough track. Hope some of this helps,
Thanks. i had sort of given up on it but I have got a bit more experience under my belt since I got it. Keith Appleton YouTube videos help. Its had the lubricator moved from bunker to front by a previous owner and I am wondering what else has been tweeked. Trying to get hold of the first couple of Model Engineer articles on the subject from 2017.