‘97 xp no acceleration

[BusyDad]

Hi everyone, newbie here.
I’ve had lots of work done to my 97 xp (787/800) and it was running great (with a temporary set of carbs that had no accelerator pump) I totally cleaned and rebuilt another set of carbs with the accelerator pump (the ones that were originally on the ski) with a SBT kit (I now know Mikuni would have been best, I thought I was getting those and didn't up that way, so my mechanic said don’t worry and that he uses lots of those)
Anyways, I installed the rebuilt set of carbs, set high speed screws to 0 (incidentally, I tried to turn the h s screws out 1/8 & 1/4 turn and adjusted both low speed screws to 1-3/8 turns out. It starts and idles well and initially runs good but after a very short time it will not accelerate (it bogs down). I am at a loss, the high speed screw didn’t seem to make any difference in or out)
It starts fine & The is idle is good,
My question is…can I take off the h s screw caps and adjust the h s screws out more than the 1/4 ? It seems like it’s not getting
Any gas under demand

 

[rusty nail]

high speed screw 0. low speed 1.25.

 

[BusyDad]

Been there, tried that..now what?
Tweak the screws or tear the carbs off and look for a problem?

 

[rusty nail]

could be something else....fuel starvation, or carb air intake gates adjusted properly? I would probably start by eliminating potential fuel problems by installing a gravity feed accessory fuel source directly to the carb. this will bypass the fuel selector and fuel filter both of which can restrict fuel at WOT.

 

[rusty nail]

There are many feeds here that talk about only use mikuni kits on the carb rebuild and since your issues only began after you rebuilt the carb that is most likely the issue. But for me installing a accessory fuel source is very quick solution to eliminate that.

 

[rusty nail]

Because you changed to the accelerator pump carb, did you install the small plastic jet in the end of the fuel line where it enters the accelerator pump?

 

[rusty nail]

sorry, maybe that little jet is only for the 951....i am trying to find the fuel schematic for the 787 with accelerator pump to confirm.

 

[BusyDad]

Because you changed to the accelerator pump carb, did you install the small plastic jet in the end of the fuel line where it enters the accelerator pump?

Yes, I did! I didn’t notice that little restrictor and had put the old lines ready to dispose, then I watched a YouTube video that mentioned it. (I believe that it is in the output line from accel pump on the way to the injector nozzles.
Thank you though

 

[BusyDad]

I set my pop off to about 27psi, the only thing I didn’t replace is the needles and seats. But the tips of the needles looked good.

 

[Grayson]

I am having a similar issue with my 95 xp 717. Starts up and idles great but bogs down on acceleration. I have gone thru the carbs with genuine mikuni kits with needle/seat. I believe I have narrowed it down to the fuel pump check valves not sealing causing weak fuel pump. I am thinking about hooking up an external fuel pump if anybody's had experience with that?

 

[POPPS]

If you are racing,,,we all have external pumps,,,you are not rev'ing 7750,,,you just need to pull the carbs and replace the 2 nearly invisible check valves.

 

[BusyDad]

If you are racing,,,we all have external pumps,,,you are not rev'ing 7750,,,you just need to pull the carbs and replace the 2 nearly invisible check valves.

I did just replace those 2 circular transparent valves.

 

[JJinSC]

during the rebuild, did you do anything with the A-pump? Have you checked to make sure they are spraying a good stream from the a-pump circuit nozzles into the carb body when you squeeze the throttle? If not, there is your problem. Find the source of that issue.

 

[BusyDad]

during the rebuild, did you do anything with the A-pump? Have you checked to make sure they are spraying a good stream from the a-pump circuit nozzles into the carb body when you squeeze the throttle? If not, there is your problem. Find the source of that issue.

I disassembled the a-pump, but was very careful to put it back together the same way. I didn’t touch the adjusting screw on it.
Is the only way to check the flow, visually when carbs are installed?
I’ve been told (from a seadoo mechanic) that those pumps are not that important, and that whether that system works or not, the ski should still accelerate (maybe just not as well)
At this point, I think I’m going to remove the carbs and have an expert go over them.
I did change the pop off spring (one of the originals was bent) to give me 27psi
Don’t know what it could be at the point.

 

[Jtamaro]

Hi everyone, newbie here.
I’ve had lots of work done to my 97 xp (787/800) and it was running great (with a temporary set of carbs that had no accelerator pump) I totally cleaned and rebuilt another set of carbs with the accelerator pump (the ones that were originally on the ski) with a SBT kit (I now know Mikuni would have been best, I thought I was getting those and didn't up that way, so my mechanic said don’t worry and that he uses lots of those)
Anyways, I installed the rebuilt set of carbs, set high speed screws to 0 (incidentally, I tried to turn the h s screws out 1/8 & 1/4 turn and adjusted both low speed screws to 1-3/8 turns out. It starts and idles well and initially runs good but after a very short time it will not accelerate (it bogs down). I am at a loss, the high speed screw didn’t seem to make any difference in or out)
It starts fine & The is idle is good,
My question is…can I take off the h s screw caps and adjust the h s screws out more than the 1/4 ? It seems like it’s not getting
Any gas under demand

I wouldn’t think giving it more gas will be an issue (mind you I’m not a mechanic) just don’t go the other way and lean it out.