94 XP 657x low end hesitation


Hi! I've got a '94 XP with the 657x. Everything is stock apart from a set of ProK FAs I've put on (along with carb brace and outerwears). Even with the stock FA, I noticed it had a low end hesitation (I think?) and it remains with the ProKs too.

I've rejetted the high speed jets and lowered popoff. Current specs in both carbs are:
137.5 highs, 75 lows, and 21psi popoff.

I noticed a substantial high end improvement after this. Dropping popoff resulted in better low end response but still has a hesitation. I noticed it much more after riding a friend's 95 720 XP which had amazing low end response.

Am I expecting too much from the 657x, or should it be capable of the same low end response from the 95 XP? I have a set of 77.5 low speed jets I'd like to try since dropping popoff helped, maybe adding more fuel to the low circuit will help this hesitation?

Would appreciate any insight, thanks in advance!


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You need to rejet the pilot, since you are breathing in more air than stock,,rejetting the hi speed will not solve lower i
off the line issues
You need to rejet the pilot, since you are breathing in more air than stock,,rejetting the hi speed will not solve lower i
off the line issues
Thanks! I'll give that a shot. I also just realized that my fuel tank relief valve is completely dead. It vents any pressure immediately and does not hold to 2psi as it should. In the picture below, it actually appears to be broken.


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Alright, I upped the low speed jets to 77.5s and ordered a new relief valve. Also found the fuel cap gasket and water separator gasket were torn. So have those on order as well now. Will update when I test it all out again!
Seems a bit improved but still not as good as the 95XP. I see the 95 has a very high popoff spec'ed vs the 94 being very low. Some reading shows a high popoff can contribute to really crisp throttle response, which I bet is really what causes it. I'd think that the correct mix of high popoff and even more rich low speed jets would give the same crisp response.
Are you running the stock Flame arrestor with your testing? Might be easier to start out with the stock one since you have all the original parts anyways. Use this as a baseline and get it running perfect at stock then if you want to put the aftermarket flame arrestor on you could change one thing at a time until it’s right again. My brother in law had a 94 XP all stock and man that thing is peppy and crisp. You may decide you don’t even need the aftermarket flame arrestor
I agree with you about the pop off, you said you are popping off at 21 pounds, Seadoo source lists it at 19 to 35 pounds. I wonder if it would respond better with a higher pop off
Yeah, thanks! Do you recall what your brother in law's carb specs were? I think during the off season I'll bump the pilot jets a bit, maybe 82.5s and raise popoff to 35 or so. The needle seats pass the leak down test but I might go ahead and just replace them to be on the safe side there too.
Sea Doo PWC Carburetor Reference
I have no idea what the specs on his carb are, we’ve never had a reason to even look at them. I attached a link here, it has all the factory settings, jet sizes, pop off.... everything you should need to get her to stock.
Thanks! Yeah I had it at stock specs for a while and it felt the same as it does now. I'll definitely take a poke at checking it out again and playing with popoff/low speed jets once more.
Definitely sounds like a fuel issue, it’s a bit of money but if the rest of the fuel system which is really only the fuel filter, fuel valve is all holding vacuum the back to OEM carb kit from OSD Marine has always fixed any fueling issues for me, it comes with new needle and seat, spring and in your case I would order the new needle lever and pin just in case anyone’s been bending it in the past to try and reach desired pop off. I’ve never had to bend the lever myself. You will get it, that’s a fun machine. Good luck