Had a funny one the other day. This falls under my favorite saying "Never Overlook The Obvious". This didn't happen on a saw but it probably could and this is why I'm passing it along. The machine is lawnmower with a 5.5HP Honda motor. About a week and a half ago I needed to mow the lawn so I gassed up and started it up. Started fine but after about 20-30 sec. it quit, no skipping or stumbling just stopped. Gave it another pull, started right up ran excellent same amount of time and stopped. It did this as many times as I wanted to start it. Didn't matter if was at idle or wide open it would run fine and stop. So I got out the tools pulled the sparkplug and grounded it, gave it a pull, nice blue spark. OK ;says I, an obvious fuel issue. Pulled the drain plug and drained the bowl. Gas looked OK, no water or crap so I put the plug back in and pulled it over started right up ran 20-30 sec and quit! Pulled the carb, took it all apart, blew it out, everything seemed fine so I put it back together, started right up annnnd 20-30 sec it quit. Pulled the carb again and the fuel tank. Drained and washed out the tank, checked the fuel line and petcock, all OK. Took the carb apart again and did notice that the main jet was loose and had moved down some in the tube it screws into and was partially obstructing the fuel inlet from the bowl. AHHA says I!! There is the problem. Removed the jet and emulsion tube and checked for any dirt etc. and put it back together. Confident I had the situation well under control but by now it was dark I decided to mow the lawn the next evening.
Next day I filled the tank, gave her a pull started right up....you guessed it, ran 20-30 sec and quit. Needless to say I was about ready to set fire to to this jap mower from hell. Didn't get the lawn mowed but the wife and I went on vacation for a week had a great time but when we got back the damn lawn looked like the Munsters lived there. So Mon. I took the carb apart one more time hopeful that I had missed something the first 3-4 times I had it apart. One thing I had thought of was to check and make sure the bowl vent wasn't obstructed in some way. NOPE everything was in good order.
I came in defeated and angry and had a beer and then decided it had to be the coil......so I got on line and searched the Internet for 5.5 HP Honda motors well a coil for a 5.5 is around $50.00 + shipping so I kept searching. I eventually ended up at an OPE website/forum that concerned itself with lawnmowers and snowblowers and such. In a few minutes I had found a fellow with the exact same trouble I was having. He had found two previous posters that also had the same trouble. all with 5.5 HP Hondas. He did what they did and bought a new NGK plug and the problem was gone. So yesterday I went to the local parts store and purchased a brand new NGK for a total of $2.19 and went home and mowed the lawn.....!!!!!!
NEVER, NEVER, EVER Overlook The Obvious!!!!!
Now I know a lot of you guys are thinking "Hell I'd have done that first off"
Well perhaps I should have but I have bought so many parts saws and no mater what is actually wrong them they about all have a brand new plug installed that never was run. I probably have 2 doz new Champions that fit the older Jreds. I'll never have to buy a plug again for those old guys!!
In my own defense, I have never had a plug do what this one did. They are either fouled, worn out, won't start or won't run without skipping or whatever erratic behavior they exhibit. Never had one start and run the motor perfect and then not. Never had any other Honda motors either.
The end result though is that I over thought the problem and OVERLOOKED the Obvious!!
Sorry this is such a long post but perhaps it may help someone else not over think a problem.