Carburetor Adjustments help please

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Koopy

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Have a 1997 spx 787 and specs {http://www.seadoosource.com/carbreference.html}
call for LOW- 1 HIGH- (MAG-0 PTO-1/2)
The 1996 xp with the same engine and carb jets call for LOW- 1-1/4 HIGH- 0

1\2 turn extra on the pto side is a lot of extra fuel to that cylinder

Any master tuners find this is correct or should i tune more in line with the 1996 soecs
 
Hi and welcome to the Seadoo forum.

The specifications you are using are correct, the 97 787 carbs. use an accelerator pump the 96 doesn't use the accel. pump, thus the difference in the specs. The hi/lo settings only have an effect at low speeds, once you're at higher speeds to WOT they have no effect.

Personally, unless there is a problem with the carbs., I have found the stock settings work best, you can experiment some if you want, but I wouldn't vary any more than 1/2 turn from stock, and you won't be able to tell until the your ski is under load in the water, which in Toronto I would imagine would be next summer.

Lou
 
Actually Lou, I dont know about the 97 SPX. I dont believe they have the accelerator pump on that model. Only reason I say that is that I know my buddy has a 97 spx that is a one owner from his family. The carbs have never been changed out and they didnt have the accelerator pump.

But that being said. I would follow the stock specs for sure.

Oh, and wouldnt the high speed jet have an effect at high speed? Not low speed? Lol.
 
The lows are 1 turn out on both carbs, the MAG high is closed and the PTO high is 1/2. 97 should not have an Accel pump. Make sure you actually turn the needle, if the carb has never been adjusted before and you turn the plastic cap chances are you didn't turn the actual needle cause it could be stuck. Pop the cap and make the adjustment--bottoming out the needle ever so slightly first, then come out the 1/2 turn.

Service manual calls for 1 turn out on the lows for the 96 XP, not 1-1/4
 
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Ok ok so I got a 97 spx. No accel pump on carbs. ( sorry Lou ) and when I rebuilt carbs I set both high speed needles at 0. It ran PERFECT all summer! That feels like a long time ago! 20 degrees out!
 
manolocross said:
Ok ok so I got a 97 spx. No accel pump on carbs. ( sorry Lou ) and when I rebuilt carbs I set both high speed needles at 0. It ran PERFECT all summer! That feels like a long time ago! 20 degrees out!
Click to expand...

Just curious, what altitude are you guys at?
 
Have 2 spx,s 1998 has the Accel pump
the 1997 doesn't

Just currious as to the 1996 has same carbs and jeting as the 1997spx
and understand there is a slight lean issue on the pto side

But stiil find 1/2 turn extra on the pto side a lot of extra fuel to that side
when the 1996 xp are both equal on the high speed needles
 
I don't get it either, it's the same engine... did they just realize in 97 that they have to compensate for the crank torquing and changing timing? group K were the ones who proposed this, and I guess it stuck, but why not go back and change all the specs for the 96 models? I heard that the 97SPX waterbox was the best flowing one, maybe less restriction means it needs more fuel to not starve? But why only on the rear cyl? Could it be b/c the pump is on the MAG carb and the PTO might be getting a bit less fuel pressure at WOT? Do they do this on any other model boat?
 
I'm not sure that's a dead even trade, but that's a nice offer. Problem would be the distance too.

I don't really want to, but I bought a boat a few weeks ago, and really can't justify 4 skis... but the SPX would be a fun play thing.

I do have a single trailer lol. and one itty bitty SPX wouldn't take up much room ;)

I'd have a 99 GSX LTD (red, carb 951) and 2000 GTX red, carb, 951.

they make a nice pair... my buddy wanted this exact setup, and i was like... that would make a nice matching pair... so i stumbled on the GSX (wouldn't run) and GTX (also wouldn't run)... Fixed them both, and now they both work great... i just... can't ride 4 ski's all at the same time lol. that and I'm running out of room in the garages!

My wife and I used them a bunch of times this summer. Neither gave us trouble. The speedo on the GTX does not work, nor does the fuel gauge on .. either I think? (All fixable, but I wasn't too worried).
 

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IDoSeaDoo said:
I don't get it either, it's the same engine... did they just realize in 97 that they have to compensate for the crank torquing and changing timing? group K were the ones who proposed this, and I guess it stuck, but why not go back and change all the specs for the 96 models? I heard that the 97SPX waterbox was the best flowing one, maybe less restriction means it needs more fuel to not starve? But why only on the rear cyl? Could it be b/c the pump is on the MAG carb and the PTO might be getting a bit less fuel pressure at WOT? Do they do this on any other model boat?
Click to expand...

Skidoo has put different carbs(jetting) on the PTO of liquid cooled dual carb sleds way back in the 70's and 80's. I've seen enough sleds fry the PTO slug, even on my vintage Yamaha sled, so it's not locked down to BRP. So anything to toss a little extra fuel in there to cool it down is helpful to prevent a seizure. The Jetboats with the 800's get this 1/2 turn as well, maybe the 720's too??. My 96's never had any issue back in the day and I rode them hard. Seadoo probably saw warranty failures and figured to compensate for it jut turn it up for some more fuel to curb the issue. It's like when guys put a factory spec pipe on a 720, the PTO carb needs way more fuel, or BOOM.
 
SabrToothSqrl said:
I'm not sure that's a dead even trade, but that's a nice offer. Problem would be the distance too.

I don't really want to, but I bought a boat a few weeks ago, and really can't justify 4 skis... but the SPX would be a fun play thing.

I do have a single trailer lol. and one itty bitty SPX wouldn't take up much room ;)

I'd have a 99 GSX LTD (red, carb 951) and 2000 GTX red, carb, 951.

they make a nice pair... my buddy wanted this exact setup, and i was like... that would make a nice matching pair... so i stumbled on the GSX (wouldn't run) and GTX (also wouldn't run)... Fixed them both, and now they both work great... i just... can't ride 4 ski's all at the same time lol. that and I'm running out of room in the garages!

My wife and I used them a bunch of times this summer. Neither gave us trouble. The speedo on the GTX does not work, nor does the fuel gauge on .. either I think? (All fixable, but I wasn't too worried).
Click to expand...

Yep, you might need to pony up some cash with that trade for the rare 99 SPX. You can get a GSX and a GTX all day long, LOL.
 
Yea yea... 3 seaters sell the fastest around here. I just put for sale on it, and it's gone in a week. especially if I ride them with the for sale sign on 'em...
 
racerxxx said:
Mano is riding at sea level

Where I ride is @ sea level (OC, NJ), Near Philly is like 30' above sea level, another place I go is about 100' above sea level.



If you curious KC,MO is between 800' and 900' above sea level
Click to expand...

Gotcha, I'm jealous, I am at 4200 ish and the places I ride go as high as 5500+. Needless to say I am always trying to fine tune mine.
 
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