1997.5 GSX Limited will not start

[water toys]

Hi, looking for advice before I buy carburetors.
I removed the tempo fuel lines and rebuilt the carbs. I used a 1998 rebuild kit and found out after reading threads here, that 1997.5 with the 951 white motor was a kind of 1 off-emissions control thing. and had a much lower pop-off pressure than the 1998.
The ski does the notorious huge exhaust bang. blew the rear rubber exhaust boot apart. I figured it was flooding and igniting the fuel in the exhaust. but now I am questioning ignition timing. I am not sure how that could change. I have excellent spark and good compression. The ski cranks over doing nothing until you give it lots of choke and then backfires sometimes violently. I tried removing plugs and turning it over to clear fuel then crank it with the gas off and nothing. then I manually squirted gas in the carbs and it only pops with small backfires, even tried some either with the same results.
Could the backfires change the timing? how would I check ignition timing? the ski only has 1 coil.
Thanks
Jeff

 

[2strokeboy]

Hi, looking for advice before I buy carburetors.
I removed the tempo fuel lines and rebuilt the carbs. I used a 1998 rebuild kit and found out after reading threads here, that 1997.5 with the 951 white motor was a kind of 1 off-emissions control thing. and had a much lower pop-off pressure than the 1998.
The ski does the notorious huge exhaust bang. blew the rear rubber exhaust boot apart. I figured it was flooding and igniting the fuel in the exhaust. but now I am questioning ignition timing. I am not sure how that could change. I have excellent spark and good compression. The ski cranks over doing nothing until you give it lots of choke and then backfires sometimes violently. I tried removing plugs and turning it over to clear fuel then crank it with the gas off and nothing. then I manually squirted gas in the carbs and it only pops with small backfires, even tried some either with the same results.
Could the backfires change the timing? how would I check ignition timing? the ski only has 1 coil.
Thanks

Im pretty sure the ski should have 2 coils not 1 but i think this is a timing issue. Have you ever replaced engine with a donor or a previous owner done that?

 

[water toys]

Thanks for the reply, I have owned it since almost new. I think they went to 2 coils in 1998 or 1999. It makes sense it is simply flooding as the work was done to the carbs which are under the exhaust and a chore to remove. but I can not get it to run at all even with the gas turned off and cranking like crazy.

 

[tobytd]

Dual coil 99 and up
did you replace the needles and seats when carbs were rebuilt?
Genuine Mikuni kits ?

 

[water toys]

Replaced seat O rings. Tested pop-off pressure and it was near 40 psi. Then put original springs back in and down to low 20s. Not a Genuine Mikuni kit, which I'm sure is a mistake. the 97.5 evidently has a way lower pop-off pressure than the 98 rebuild kit that I got. I was going to buy used 98 carbs and rebuild them with a Mikuni kit, but I'm just hesitant that I missed something else. example ignition timing? original motor and everything else compression 118 and 120lbs.