1997 Sea Doo XP - Hesitation from Idle to Low Throttle & Uncommon Stall off Throttle

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bluebobbo

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Hey everyone, I'm a total newbie with PWC's (since I just got mine last weekend), so excuse my bad explanation of the problem... Doing the best I can. I read nearly all the threads on this type of issue for about 5 hours yesterday, so I'm aware of all the potential causes but I guess I need a more "newbie friendly" explanation/order as to what is the possible problem/solution and what people's experiences have been as to the "easiest" fix. So we're working with a 97 XP here, and here's the context and symptoms:

Context
Went for a ride last weekend and noticed right away that the first time I press the throttle, nothing happened. I would have to let off and then press the throttle again a second time before it worked. However, the second time, it would feel "laggy" or "hesitant" when going from idle to low speed/low throttle. Rode around for about 15-20 minutes. Once it gets into low throttle everything worked fine. Then, at one point I was idling in the middle of the lake to talk to the GF and then when I went to low throttle, it stalled. Took a few starts to get it to run again. Lastly, when I got back home I noticed a significant fuel smell coming from the engine compartment and the rear compartment where the impeller and driveshaft are. I know people will say it's "normal" but I have two 97 XP's and my other one I can barely smell any fuel which to me it seems more normal (but what do I know).

Symptoms
  1. Does not respond when pressing throttle first time, but responds second time. Second time is laggy/hestitant.
  2. At one point it stalled going from idle to low throttle on the first press.
  3. Smell of fuel from engine compartment and rear compartment. My other XP has very mild smell that seems more "normal"
  4. Fuel selector does not "click" when switched to any other option On/Off/Res. It has this weird "smoothness" to it when I turn so I suspect something is wrong here. My other XP clicks like a switch should be.

Thoughts
So I expect a lot of people to say rebuild the carb, fuel lines, etc. because yes I am on the grey OEM lines. But my thing is that I'd like to get a few more good rides out of this (if possible) before I call it a season and start gutting it out to rebuild and restore everything. There is really only 2-3 more weekends for us in Wisconsin. Where can I start as far as the easiest/cheapest of potential fixes. I realize doing the easiest stuff may end with me having to do the entire rebuild of carb and fuel lines but that's okay with me (it's inevitable anyway).

What scares me is the smell of fuel, and that I feel like if I can find this, it'll actually fix the hesitation so I don't want to go too deep into the repair to start. So far here are my ideas that I've gathered from other threads. Please let me know your input and if I should/should not do these things, etc.:

Working List of What to Do
  1. Change spark plugs.
  2. Try running on Res. This will tell me if there's gunk in the fuel selector valve? Which can then be cleaned or replaced.

With these symptoms considered, what else should I do after these two things? I'm not sure I want to go as far as adjusting the low speed screws right away if there is something less complex I can do. I can take any pictures/videos if needed (and if possible). Any help is much appreciated!
 
Start ski then shut off, pull off flame arrestor, look down carb throats and you will see a small nozzle sticking out the side of each carb throat, quickly squeeze throttle and you should see fuel squirting from nozzles.

FYI swap out those lines and rebuild carbs with OEM kits. Until then your ski is a ticking time bomb.
 
I would say the same. Replace the fuel lines and rebuild the carbs with OEM parts. The needles and seats are separate. You can tinker with a lot of things, but my guess is you'll continue to have the issue until you address the most likely problem with the fuel lines an carbs. At the very least, take the carbs apart and clean them. Of course, if you might as well rebuild them if you take them apart enough to clean them.

You'll probably find numerous issues like clogged fuel screens, sticky needles, and clogged jets. If the needles aren't seating good, fuel will continue to flood the engine and cause the gas smell.
 
Is it necessary to siphon all the fuel when I do the carb rebuild and replacement of fuel lines?

I'll check the nozzles and flame arrester. Thanks!
 
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Read up on carb rebuilding. The Sticky above the forum has good instructions on cleaning and where what part comes into play when running. Use search function above to find instructions on rebuilds and problems.
OSD.com has rebuild kits and pop off testers for $25 or so. You need to test pop off, when you rebuild one of these carburetors. It can be used to find air leaks too. Repair manuals are available to free on the Internet.
Try the pull the choke test. When it bogs pull choke and see if that clears problem. If the engine improves it is lean. If it stalls it is rich. Low speed adjustments will make very little difference. The pop off is probably too high for the ski. The feed back low speed check valve can be another problem. I would be careful running the ski. Fuel is LIFE, it carries oil to the important lube points. Better to find problem then have a $1,200+ mistake, meaning a rebuilt engine. The old owner sold it because it had the problem. Not willing to fix the problem! Or smart enough!
 
Start ski then shut off, pull off flame arrestor, look down carb throats and you will see a small nozzle sticking out the side of each carb throat, quickly squeeze throttle and you should see fuel squirting from nozzles.

FYI swap out those lines and rebuild carbs with OEM kits. Until then your ski is a ticking time bomb.

Do I need to start then turn off the ski to check that the nozzles are squirting fuel?
 
Update: I have taken out the flame arrestor to check the carbs and everything looks great. Seems like the past owners used only premium or fuels without ethanol because everything looks good in the carbs. *I have not tested out the nozzles spraying yet, I will do that today.

Secondly, I still have not found the source of the gas smell. I've been making inspections on just about every joint/barb/line by looking and touching/smelling it all. Fuel filter is fine. I also removed the seat to get to the fuel sending unit to see if there's a leak or issues there. Nothing. The gas smell has not gotten worse, if anything it got a little less gassy smelling. The worse of the gas smell happened after operation.

I'm still leery of operating it, so whatever it is I'd like to fix it before taking it out again. Any new thoughts after this update?

My next step is to take out the fuel selector valve and replace it. Do I need to siphon the gas for this?
 
No, you do not need to remove the tank to replace the fuel selector valve. If you have the fuel selector in the OFF position, I would expect there to be less gas odors if the motor is flooding. Did you take the carbs off and clean them or just removed the flame arrestor and looked in the throats?

Attached is a picture of one of the fuel filters I removed from my carbs when I took them apart. That black hard substance is from the gray fuel lines.

plugged fuel filter.jpg
 
No, you do not need to remove the tank to replace the fuel selector valve. If you have the fuel selector in the OFF position, I would expect there to be less gas odors if the motor is flooding. Did you take the carbs off and clean them or just removed the flame arrestor and looked in the throats?

Attached is a picture of one of the fuel filters I removed from my carbs when I took them apart. That black hard substance is from the gray fuel lines.

View attachment 41210

I just visually inspected the carbs, didn't take out to clean. Oh I thought the fuel filter was the white plastic thing hanging at the top of the hull? Where is that little black one located? I'll check the little black fuel filter.
 
The white plastic thing is the water separator. The filters are inside the carbs. I'll attach a link to a youtube video that will give you an idea of taking them apart. I skipped around on the video and it seems to cover the how to's of disassembly. The images are a parts diagram. The filter is #7.

[video=youtube_share;AvyvgyQz5pU]https://youtu.be/AvyvgyQz5pU[/video]

View attachment Mikuni SBN Parts Diagram.pdf
 
I was finally able to rebuild the carbs. Surprisingly, everything looked great internally. Seems like the previous owners used premium fuel regularly. I didn't find any gunk in filters, only a little bit at the end of the lines.

Anyway, I replaced the grey lines and the fuel valve selector. I also rebuilt and cleaned the carbs with OEM Mikuni parts from OSDParts. I found that my accelerator pump needle was clogged so I carb cleaned that out until it would spray through (tested). After all this work, and getting it in the water... No success. Here are the current symptoms:

1. Bogs from idle to low throttle (sounds like gargling). It bogs for a good 4-5 seconds if I keep it on low throttle (like 1/3rd or less) until I push the throttle full and then BOOM just takes off and runs great at high speeds.
2. It idles rough.

So far, I have only tried closing the low speed screws. I figured the bog was because it was too rich, so I closed them out about 1/8th turn. There was not a huge difference in the bog. Should I close it a little more? What other things should I look at?

Thanks
 
My guess it that the 3 small holes in the carb are clogged.

You need to pull them back apart and remove the small pilot jet then blow carb cleaner through until you see 3 hard streams.

Next question did you check the pop off pressure?

Did you change the needle and seats?

Did you change the springs?

Your carb setting should be all stock, even the adjustment screws.
 
What 3 holes are you referring to?

I quickly checked pop off pressure, but frankly my tubing on the tester was not tight on the valve and it was leaking so it wasn't holding like it should. I'll need to fix my tester and retry.

I changed needles and seats with OEM Mikuni. I did not change the springs, I used whatever was in there.

The one thing I did not do is take out the carburetor body, because I stripped the screw... Any advice on this difficult screw?
 
I would say that is your issue.

Behind that block with the two phillips screws is a mylar check valve that needs to be replaced, the main jet and the pilot jet. All these need to be clean. Behind the pilot jet are three small holes that bleed fuel from the pilot jet and low speed screw into the throat of the carb. With these 3 small holes blocked or dirty you will get the exact symptoms you are having.

Use either a hammer impact screwdriver and if that doesn't work drill the head off the screw then remove the remaining part once the aluminum block is out.

BTW: these are not phillips screws, they are JIS Japanese Industrial Standard. With the correct JIS screwdriver you will not strip them out.
 
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