503 Won't fire

[steveo88 0]

If nothing else is working I would check compression. Allmotors 2 or 4 stroke require fuel, spark and compression to run. Ihave seen 50 hrs on a 2 stroke require piston rings to bring power up to specs. I have rebuilt lots of performance (was in the business) 2stroke motors (bikes, sleds, quads)and a slight reduction in compress would surprise you in ahurry Just a thought ??!!!.Regards

[IFMT 36]

88 hrs on a major overhaul. Just checking but this included crank seals right? Cheers.

[Bandit 286]

Yes , everything brand new. I worked on it yesterday. These are the things I changed.

1. Replaced primer that was pumping bubbles.

2. New plugs with gap reset to .016

3. Rebuilt recoil.

4. Changed main jet from 158 to 162.

 Three pumps of the primer, 3 pulls and it started. With a little tweaking of my mixture control away I went. A little more tweaking at cruise in ran purrrrfect. Again time will tell. Once the weather clears again I will try it again. Keeping my fingers crossed.