1997 seadoo speedster help with stalling

[boggs]

My speedster will sometimes stall when I try to ramp up to full throttle. I had my carb rebuilt last year and my compression numbers are really good. Not really sure we're to go from here. Could my settings be off on the carb? It starts easy and if I can get by the stall upon acceleration then it is fine. Any help would be great.

 

[Waterluvr]

If you look inside the throttle body your carbs have two very small fuel delivery points right in back of the closed throttle plates that deliver the initial 25% of fuel before air velocity pulls the diaphragm open and the bombsight starts to add in the remaining 75% of fuel from the main jet circuit.

There's a larger opening on the end of the pilot circuit on the inside face of the throttle plates that allows manifold pressure into the circuit to regulate the pop off of the needle and seat.

Any reduction of flow from the pilot side from an obstruction in the circuit or pop off set to high will cause the issue your having transitioning past the first 1/4 of throttle operation. Find that and fix it asap, that's a lean hesitation and the fastest way to smear a piston coming back off high rpm operation.

 

[boggs]

Thank you so much for the reply. Do you happen to have a pic of it? Also what do you think may be causing it? I would love to get this fixed.

 

[Waterluvr]

Sorry no pictures of your obstructed pilot circuit or pop off setting, see my previous reply it's one or the other or a combination of both the carbs need to come off and be evaluated for function to determine where the problem(s) are it's a little more complicated than show and tell will remedy.

Your issue is one or a combination of two things, debris or electrolysis obstructing the circuit passageway from the pilot jet to point of exit in the throttle body or an issue with the the control arm/pop off pressure.

The single carb installation on the '97 Speedster leaves no room for error in function and it will destroy an engine in a hurry with a lean hesitation. Unlike twin carb installations with some wiggle room for error and adjustment on the pilot circuits that single carb has to be pretty much in perfect working order to meet the fuel demand of the engine before it leans out and smears the pistons from lean seizures.

 

[Waterluvr]

This might help give you a better idea of where everything is, bear in mind this is a cutaway representation showing the throttle plate wide open but if you remove the carb and use an 8" cable tie to hold open the throttle shaft you can see inside the throttle body and clean it and reference the drawing to see the two small fuel exit points from the pilot circuit that are one of the usual suspects.

 

[Albysure]

I had a 98 sportster 1800 and had the same issue...it would stall in midrange acceleration unless I pumped the throttle...I rebuilt it myself twice and dealer several times with same result...couldn't take it no more so I went on ebay and found a shop in California who sold replacement carbs for $189.00....I was already way over that trying just to fix my factory carb...it was a direct bolt on and I didn't need to change jets or needle and seat...drove it for years problome free after that...sold it and upgraded to a 07 challenger 180 but I still the guy out and he says running great...

Carbs there self can go bad over time from piting and ethonal gas...

 

[boggs]

Does anyone happen to know the low speed, height speed and needle valve size? Want to make sure I buy the same new carb. I already have $150 into this carb and I have the same disappointing result.

 

[nate_4_01]

Waterluvr, could this be something like I had last year with the clogged accelerator pump?
I had bogging issues really bad as you accelerated and it was a clogged pump.

 

[Waterluvr]

Waterluvr, could this be something like I had last year with the clogged accelerator pump?
I had bogging issues really bad as you accelerated and it was a clogged pump.

Yes, only in this case one carb runs the entire motor versus the dual carb I helped you bring back to life which makes it even more critical there's enough volume flowing on the pilot circuit. The main circuit on these are huge in comparison and just not prone to being hard to clean and restore I have never had a high circuit fail a flow test after cleaning but certainly can't say that for the low side.