Spent Thursday tinkering with my recent Ebay purchase WAH358. As I mentioned before, the carb was missing when I bought the engine as it had apparently been 'work in progress' when the vendor's father (a Mr Yallop) passed away. However, I came away with a bag of likely looking bits gleaned from around the shed and sure enough everything necessary appeared to be there.
I had already checked for a decent spark so, carb assembled and fitted, I fed it some fuel (I used some 24:1 I already had mixed - anyone know the correct ratio?) and gave a few experimental swings of the starting handle. I could feel the odd attempt to fire but it was kicking back so I checked the timing - must have been well over 45 deg BTDC! I don't know the correct figure but I reset it to 'a bit' BTDC, feeling the piston crown with a finger through the spark plug hole. A few more swings produced the odd cough but nothing sustainable. Though the he plug seemed ok and certainly sparked well enough outside the engine, remembering the words of a wise old Viking of our aquaintance I tried a brand new one and away she went :-)
This first run bas brought to a smokey halt when a sticking float needle drowned the poor thing with fuel but, that attended to and the oily filth drained from the crank case, it fired up again quite quickly but seemed reluctant to pick up speed and sit on the governor. I fiddled about for half an hour or so trying to improve the running then, as it was getting dark, I decided to call it a day and switched the fuel off. After a few seconds the engine cleared it's throat and ran up to governed speed, sitting there until, with a few spits through the carb, it finally came to a halt.
The obvious conclusion is that it is running too rich, the carb needle is a number 3 which, looking at a few old SEM articles, is apparently correct for the 1 1/2 hp 'A' engines, but what should the jet size be? When I built up the carb from my bag of bits I had a choice of two - I went for the one stamped 3 to match the needle, the other is stamped 2 but looks identical. Another unknown is the mixture control cam which raises and lowers the needle for starting - the one in the bag has a distinctly home made look about it.
Clearly a bit more tinkering is needed - do we have a resident expert on these engines? A handbook would be useful (checked IF after paying my tenner, but no luck)