Thanks again for everyone's inputs! I am first going to look at possible ignition problems. And if I can't find anything there, I am going to build Brian's engine starter system for the drill and also his compression tester. Then I can try all of the suggestions you all have given me on compression and on the fuel system.
Hi Johwen here. Check the colour of the spark, Is it a blue spark or yellow? It should be blue. It would appear to me you should be getting pops and bangs if you have ignition even if if won't continue to run because of timing, even gasket leaks and carburation. If you have any evidence of fuel in the combustion chamber then it can only be ignition. These are my thoughts. John
Thanks, John. I pulled the spark plug, turned off the lights, and looked at the spark. It was white-blue, much like an oxy-acetylene oxidizing flame. It definitely wasn't yellow. And while it was a small spark, it was quite bright.
You said :
"the plug sparked when expected, although that plug spark looked puny to me."
From my experience with old motorbikes, it sounds to me like the spark is failing under compression, you should get quite a long spark from the HT lead without the spark plug, at least 1/4 inch, (take care it bites) if not it could be the coil. It looks like your using an old coil, the insulation may be cracked or breaking down internally, if you can test when dark you can sometimes see the it sparking across the insulation on the coil.
Thanks Minibrix. I disconnected the HT lead from the spark plug and put it across from ground. It started arching once it was within 5/8" of ground. A loud, orange-yellow spark that did look menacing. As far as the coil goes, the one in the photo is left over from a tune-up years ago. I bench tested the primary and secondary coil resistances and both checked OK. But I switched that old coil out with a new one anyway and see no noticeable difference.
I agree it sounds like a ignition problem, if the spark plug is coming out damp then no ignition is taking place. I would suggest a weak spark, it my look good outside the cylinder but when under compression is a different matter. You are looking for a fat dark blue spark outside not a wishy washy pale blue.
bobden72: Thanks . I just checked the spark again outside the cylinder. It's bright, but whitish-blue. Definitely not dark blue. Thoughts?
The car coil should give you a nice hot blue spark that will jump a 1/4 inch gap easily even if you are just flicking the motor over by hand .
Thanks, XD351: I just laid the HT lead 1/4" from ground and turned the engine over by hand. The spark that jumped the gap is orange-yellow, not hot blue. Since I had already changed out the coil, I went ahead and switched to a different condenser. That spark is still definitely orange-yellow. I am fairly certain my ignition set-up is the same as others who have been successful starting their Websters. So maybe I am missing something glaring. Thoughts?
hi gents
My first time posting anything on here, just joined, Question, does this engine have a full size spark plug or a "model size" one? the ignition coil, is it a "full" 12volt unit or one which needs a ballast resistor? My reasons for asking are, a miniature type spark plug can be "overwhelmed" by the voltage from a full size car type coil, also running a ballast resisted coil without a b/r would be like running a 12volt system on 18-24volts!
this could cause the spark to track across the plug insulator when installed. you could also have a faulty condensor (even if it's a new one). something else to check. Doug.
Thanks for your thoughts, Doug. Several others have built the same engine with the same ignition ignition design as mine, and their engines run fine. I think I am missing something fundamental. Would appreciate any further input.
