90 Stock carb settings?

[edomund]

I just picked up my 1st Yamaha Superjet. I've always had Kawsakis and still have a X2, so the Yamahas are new to me. The ski is bone stock.

Can someone tell me the stock screw settings (turns out) and jet sizes for the low and high jets and spring/needle combo. I just need a starting place to tune from and I couldnt find anything using search for a stock setup.

The ski runs OK when cold, but when I fall off or stop in the water for awhile to talk to someone it won't start again. When I pull the plugs they are wet with fuel. If I let the ski sit overnight it will fire up again.

I have 165-170 PSI compression, have spark, and fuel (wont fire even using primer).

Thanks in advance,
Ed

 

[SUPERTUNE]

Rebuild the carb, must have a bad needle valve if it floods when hot after you shut it off, but next day fires up real easy and quick with no chocking or priming.
I'm going off a old brain here as I don't think I have looked at stock jetting in 15 years...
130 H jet
115 L jet
1.5 needle valve
115 gram spring (gold or the new bright chrome one now)
1 1/2 turn out for the high adjuster
2 1/8 for the low adjuster

Note: Use only genuine Mikuni kits and parts!
I'd even use a 120 low jet for better throttle response on a stocker.

 

[edomund]

OK thanks, I'll try a carb rebuild. It does fire up easy the next day with no choke or primer.

I took it apart and checked the jets and it has 120 low and 115 high. Should I change the high jet to have a larger one than the low?
My 650 X2 has a 44sbn with 120 L & 150 H. 115 H seems small for a 650 Superjet.

 

[SUPERTUNE]

I did go and look at the Riva parts finder and the 91' 650 used 115 high and 120 low, when I looked up the 95' 701 61X engine showed a 135 H and 115 low...

 

[edomund]

Thanks for looking that up, that's what I found also but wasn't sure if it was right because the microfiche I saw said 120 & 15. Figured it meant 115.

So do most people run the stock jetting on stock skis or is there a better setup? The only aftermarket thing I have is a flame arrestor.

Thanks

 

[SUPERTUNE]

Then that means, it's NOT stock! so yes re-jetting will always help it run better!
I like a richer low jets for this market, as all you freestyler's just want engine to hit hard right off idle, for this to work you need richer than normal low speed jets.

 

[edomund]

Sorry I should've clarified my question about the FA. I have the stock FA on right now but I have an aftermarket one on my X2 that I'm going to swap later. I wanted to get it running correctly in stock form 1st.