Please Help! 1995 XP bogging at full throttle after carb rebuild - fuel pressure?

[BryceW]

I’m looking for some expert advice! I have a used 1995 XP that I have been working on. I replaced all the gray fuel lines, installed a new fuel selector, cleaned the carbs (twice), and eventually got a minkuni rebuild kit for the dual carbs. The low and high needles are set to stock. I did try the high speed at 1/4 turn out also. At 1/4 turn the plugs are a little wet, and at 0 the are brown in color and dry (new plugs also). Someone also installed a fuel primer…which I’m pretty sure does not work, and I’m at a loss to figure out what is happening.

The ski starts great, idles great, and get up to speed with really no issues. When going full throttle, after anywhere from 10 seconds to 35 seconds, it suddenly bogs down. I usually feather the throttle and it comes back, if I keep it pegged it will also eventually come back, and only a few times will it die.

Prior owner replaced the fuel filter with a clear (auto one) fuel filter (likely paper) where I can see both fuel, plus some air in the filter. It’s between the baffle and the carb.

The primer is installed off a vent line, and “T-s” up into the primer plunger. There is then a thin little yellow hose going to 1 carb…someone installed the primer on the “mag?” carb only I believe - the other carb looks to have been drilled, but the brass nipple is not there and it is sealed.

The ski runs great…until it bogs…then runs great again. Ugh!

And there is one more thing I’m not sure of - there looks to be a check valve on the port side of the ski, but also one on the starboard side out the hull?

I have not checked the rectifier…maybe this is bad? I also don’t have a pressure test tool so it may be a fuel line leak?

- should there be a thru-hull check valve on the starboard side?

- could the clear “auto” fuel filter be restricting the fuel at high speed?

Any help or ideas would be greatly appreciated! I did run it at “on” and “res” for a while also…and same issue.

Thanks everyone!

 

[burtshaver2021]

Hi, I probably won’t remember all from your post but big yes, get rid of that automotive fuel filter and put the original one back in, they won’t be hard to find. That’s probably your problem right there, sounds like your running out of fuel at full throttle when it’s really requiring a lot and that automotive filter is restricting the flow. I think you said your running clear fuel lines? I’ve never had good luck with them but get rid of that fuel filter first, maybe the lines are ok. I believe port side is fuel pressure relief valve and starboard side is battery vent but I would have to check my 95XP to be sure. I would not keep running it with the fuel restriction, it could be wearing the engine prematurely. You could try taking that filter out and run it with no filter for a ride, but definitely get an OEM filter/water seperator as soon as you can. Not that I think your high and low screw settings are your problem but what did you set them at?

 

[BryceW]

I replaced the gray lines with black lines. The low needle is 1 and 3/4, and the high is set at 0. I tried the high at 1/4, and it bogs about the same.

It’s strange because it’s running good, and then there is a little hesitation when running 3/4 to full throttle, and then it bogs down to about 12-15 mph (or less)…then it will kick back in and go back to full throttle.

I will definitely switch out the fuel filter to see if that makes the difference.

It definitely seems like it’s starving of fuel…it does not cough or sputter at all… just a sudden bog as if there is not enough fuel. When I first picked it up it was bogging and got so bad it would not run more than 8 mph…but that was due to carb filters being totally blocked by the gray lines.

 

[Grim]

Does this model have rave valves? If so check those out make sure they are c lean and working correctly.

 

[Stevie96xp]

Does this model have rave valves? If so check those out make sure they are c lean and working correctly.

This model has the 717 no raves on this girl

 

[BryceW]

You’re correct, no rave valves. I ordered the OEM fuel filter assembly and will give that a try.

Also - does anyone know if the primer plunger (aftermarket) should have pressure or some sort of ‘spring’ action when pulled? This one has the primer plunger, but I see absolutely no fuel at all in the small line and the plunge does not seem to have any sort of pressure. I also tried to pinch off the primer lines (both from the vent line and to the carb) thinking there may be some air leak which didn’t make any difference in the bogging issue.

Thanks.

 

[mikidymac]

The primer could be your issue, the are ll junk and all fail in a couple years. They will let air into the fuel system.
Never ever install them on any feed lines. The primer should only ever be installed on the return line from the carb back to the tank.

You need to stop running it until you figure this out or you will seize the engine.

 

[96GTX resto]

Does the XP have a water regulator on the waterbox? Sometimes the bellows can fail and allow the wrong volume of water to be injected into the tuned pipe. Ive heard it can cause full throttle issues if it fails.

 

[Stevie96xp]

Does the XP have a water regulator on the waterbox? Sometimes the bellows can fail and allow the wrong volume of water to be injected into the tuned pipe. Ive heard it can cause full throttle issues if it fails.

The 96 does but the 95 717 does not

 

[BryceW]

I installed the OEM fuel filter assembly, and replaced the pulse line (there was a plastic elbow and about 4 hose clamps). I figure a straight line with the bend would work and reduce the chance for air leaks.

It runs good! It does not bog down nearly as much. I do feel a slight hesitation at wide open throttle that comes and goes, but no bogging. Almost as if it wants to bog, but doesn’t?

Much more fun fo ride. I also plugged off the fuel primer line leading to the carb brass nipple, and clamped off the “t” where the primer line feeds from the return vent. I don’t think this did anything however since I’m pretty sure the primer wasn’t working anyway. I’ll either replace the primer kit, or remove the “t” fitting and do a better job plugging off the carb fitting since it starts right up anyway.

 

[Stevie96xp]

Awesome man I would richen up the high screws about an 1/8 of a turn and see if that little hesitation goes away

 

[burtshaver2021]

Awesome man I would richen up the high screws about an 1/8 of a turn and see if that little hesitation goes away

X2 with @Stevie96xp last thing you want is to be running lean, not going to hurt anything running a little rich.

 

[BryceW]

Awesome man I would richen up the high screws about an 1/8 of a turn and see if that little hesitation goes away

I will give that a shot. I originally had it about 1/4 turn out, and then went back to stock. I’ll open it up a little bit to see if that helps. Thanks!

 

[burtshaver2021]

I will give that a shot. I originally had it about 1/4 turn out, and then went back to stock. I’ll open it up a little bit to see if that helps. Thanks!

How do you like your Yamaha’s?

 

[Stevie96xp]

I will give that a shot. I originally had it about 1/4 turn out, and then went back to stock. I’ll open it up a little bit to see if that helps. Thanks!

Awesome hopefully that should do it I see a raider 1100 in there how you like it does it handle as crazy as some say or no

 

[BryceW]

I’ve only had these 4 for about a month. (Been spending most time cleaning them and polishing them up!) The Yamaha Wave Raiders are fun. One is a ‘94 and the other is a ‘95). The ‘95 sits much lower in the water for some reason (makes me feel like I need to check while out riding it for water in the hull!) They are fun and quite quick. I really can tell the difference from the Yamaha compared to the XP. The Wave Raiders seem to not turn as well, whereas the XP carves on the water better. The XP ‘95 is not as quick. In spins the Wave Raider (when it catches) wants to throw me off! I have to give the handling to the SeaDoo. I figure I could get these 4 for the price of 1 new one.

 

[Stevie96xp]

I’ve only had these 4 for about a month. (Been spending most time cleaning them and polishing them up!) The Yamaha Wave Raiders are fun. One is a ‘94 and the other is a ‘95). The ‘95 sits much lower in the water for some reason (makes me feel like I need to check while out riding it for water in the hull!) They are fun and quite quick. I really can tell the difference from the Yamaha compared to the XP. The Wave Raiders seem to not turn as well, whereas the XP carves on the water better. The XP ‘95 is not as quick. In spins the Wave Raider (when it catches) wants to throw me off! I have to give the handling to the SeaDoo. I figure I could get these 4 for the price of 1 new one.

hey there ya go. That’s pretty much what I’ve heard. 2 strokes all day. Then new skis are to dang expensive. Altho I’m also cheap as dirt

 

[mikidymac]

hey there ya go. That’s pretty much what I’ve heard. 2 strokes all day. Then new skis are to dang expensive. Altho I’m also cheap as dirt

And not as much fun. My friend sold a 1996 SPX and a 1997 GSX and bought two brand new Yamaha FX Limiteds for $40K. The first words out of is 15 yo son to me was, "the new skis are fast but boring, not as fun as the SPX."

 

[Stevie96xp]

And not as much fun. My friend sold a 1996 SPX and a 1997 GSX and bought two brand new Yamaha FX Limiteds for $40K. The first words out of is 15 yo son to me was, "the new skis are fast but boring, not as fun as the SPX."

O yeah they sure are heavy my grandparents have 2 2023 Yamaha fxs cruzers I believe there fast but they are a BOAT

 

[BryceW]

Update: more bogging - ugh! Ok…so the new OEM fuel assembly and retightening the pulse line seemed to help. We ran the ski a bunch yesterday and today. It ran well, but still had a very slight hesitation (cutting in and out slightly) at full throttle. Idle was also low. So, I opened the low speed a little to fix the idle (idles great now), and enriched the fuel by moving out the high speed needle about 1/8 of a turn from 0. The ski was running good, but all of a sudden it started to bog again. To the point where it would die. It would run great at full throttle, then bog way down…then rev back up to full throttle and so on. New fuel lines, new fuel selector, pinched off fuel primer (doesn’t work anyway), rebuilt carbs, new OEM fuel filter - any ideas? Why would it run great yesterday, and then all of a sudden bog down again? (We tried new spark plugs and it didn’t help). Only seems to bog going full throttle. Maybe a fuel line air leak?! Any ideas? Thanks!

 

[Stevie96xp]

Update: more bogging - ugh! Ok…so the new OEM fuel assembly and retightening the pulse line seemed to help. We ran the ski a bunch yesterday and today. It ran well, but still had a very slight hesitation (cutting in and out slightly) at full throttle. Idle was also low. So, I opened the low speed a little to fix the idle (idles great now), and enriched the fuel by moving out the high speed needle about 1/8 of a turn from 0. The ski was running good, but all of a sudden it started to bog again. To the point where it would die. It would run great at full throttle, then bog way down…then rev back up to full throttle and so on. New fuel lines, new fuel selector, pinched off fuel primer (doesn’t work anyway), rebuilt carbs, new OEM fuel filter - any ideas? Why would it run great yesterday, and then all of a sudden bog down again? (We tried new spark plugs and it didn’t help). Only seems to bog going full throttle. Maybe a fuel line air leak?! Any ideas? Thanks!

It sounds like you got an air leak in your fuel system somewhere. I would pressure test it for leaks