99 xp wont start

[kat]

hey.. new to forum, hope I can find the help I need here! :cheers:
i have 99 xt ltd. recently rebuilt engine (new pistons, rings, seals etc) then replaced electric fuel pump and new battery.. ran great first couple times out, only ran 3 times for total of less than 2 hours. it sat for a couple days now wont start again. It tries to turn over but only backfires then stops. replaced plugs again checked connections but still only backfiring but not completing firing up. it cranks ok and checked compression (both equal) BUT LOW psi ...why??? (what should specs be on the compression, sorry cant find manual).... please help!! this lake rat is missing her toy!!!:willy_nilly:

 

[waterboymvp]

Low PSI?

When you say low, how low? From what I have read the minimum is 100psi with a minimum between cylinders of 8psi.I have had a ski with compression in one cylinder at 70 and the other at 130 and it would start but backfire real bad. I had to bore cylinders and get new pistons and rings.
But I do have a 97 gtx with compression of 115psi at both cylinders and it runs about 48mph. You might want to check your rotary valve timing too, that will cause backfiring and hard starts too.
I'm no expert but have done alot of work to my skis with the help of this forum so I hope this can be of a little help to you. Post any updates you have and maybe someone with even more knowledge will chime in. Good luck!