90 SN 760 dual 38's not shutting o

[Galaitoto]

Since owning this ski the kill switch never worked, the previous owner just set the idle low so it wouldn't idle. I just re jetted the carbs and reinstalled. I fired it up and it reved up very high without my help, then I panicked and disconnected the battery completely, and it stayed running, so then I pulled the plug wires and that killed it. I realized I had the idle screw too high, so I backed it all the way out so it wasn't touching anything and tried it again. I was thinking by backing the idle screw all the way out, the engine would die, just like it used to. But, it just idled, lower this time, but it wouldn't die unless I pulled the plug wires. Do I have an air leak somewhere ?

 

[yamabro]

Definitely sounds like a high speed lean condition.
Air leak, carb base, intake manifold, cases, cylinder base, seals...
Fuel lines could be sucking air.

 

[Galaitoto]

Definitely sounds like a high speed lean condition.
Air leak, carb base, intake manifold, cases, cylinder base, seals...
Fuel lines could be sucking air.

Thanks, I'll keep looking. It's probably something that I did (or didn't do). I really didn't want to take them back off, but sounds like I might need to. One of the carbs was professionally rebuilt by a respected person from this site, as for the other carb, not so much, it was rebuilt by me. So that makes it easy to narrow it down to which carb might be screwed up

 

[Mdavies_02]

After inspecting fuels lines and the carbs, a leak down test will be your next best bet. You should find a how to in the Tech section.

 

[john zigler]

Could be your jetting specs....

IMO 38's are small to begin with. 760 came Stock with 44's.

1st off, you need to fix, or repair your stop switch so it works. Next do a leak down test. We need more info on your set up. Pipe? Head? What did you "re-jet" to, and why?

 

[Galaitoto]

Originally I had what the pic attachment shows, but after reading here others said that sounded too lean, so I bumped up the main to 135 and pilot to 75. Nothing else was changed. It has a protec exhaust.

 

[john zigler]

I think you are still lean.

I would go to at MINIMUM 80 pilots, and 145 mains. Start with High's and lows @ 2+ turns.

If you have a true 760 (62t case, and cyl) I would still recommend ditching the 38's and go 44's

 

[Yami-Rider]

My JetManiac 781 runs perfect on 38s, so I think the 38s should be fine. I would fix that stop start switch before went any further. As you learned, the battery has nothing to do with the ignition system on a ski with stock ignition.

 

[FlightPlanDan]

I hate to disagree with watcon, but bigger carbs = more air. 38's are plenty for 760 and beyond. What's your compression....AM head? And what fuel are you running? 87.. 89...93?
Just curious.