98 seadoo GSX limited carb tune help!!!!!

[ape1972]

Hello everyone,
Once again I need your experience! This time it's for my friends 98 seadoo GSX limited. I recently rebuilt my friends dual carbs (SBN 46). Full rebuild with new needle and seats. Pop off pressure is 18 or 19. I did the factory specs for the low and high air mixtures. I tested the ski (no load) and motor ran fine and appeared to have good throttle response. My friend to the ski out to the lake and it idled good but s little low (1200 rpm). He hit the gas and the engine bogged til it died. He restarted and had to feather the throttle until he was at full speed. Once at full speed he was good but when he let of the throttle he had to feather it to get back up to speed. This seadoo is a USA model 951 and it's been a pain in my a&@! Any running suggestions would be extremely helpful and invaluable to me. These are my current settings.

Low - 1-1/4-1-1/2
High- mag 0 Pto 1/4

Thank you all,
Adrian

 

[Matt Braley]

Sounds like the accelerator pump has failed

 

[ape1972]

Hello and thank you for you reply. I own a few Seaddos but have never worked on a GSX limited. Should I replace the pump or can the be rebuilt as well?

 

[ape1972]

When I rebuilt the carbs I did check the accelerator pump diaphragm and it looked fine.

 

[Matt Braley]

There is a check valve in there also that can fail. Perhaps the injectors are just clogged. There is on on either carb.

 

[etemplet]

Feathering the throttle to get the RPMs up generally means it is really lean. I'd be concerned about getting things too hot. I'd recheck the settings as there is some overlap between the jets and mixture settings. Could be compression.

 

[ape1972]

I thought Bogging down was a rich condition. Compression is good. My buddy went to the lake today and adjusted the low mix. He just under 2 turns and he said the top end was much better but now having idle issues (too low and dies).

 

[Chester]

Matt is right. Did you test the accelerator pump when you cleaned the carbs?

Chester

 

[ape1972]

I did not test the accelerator pump. I have never worked on a 951 so the accelerator pumps are new to me. How do I test it?

 

[Matt Braley]

I put a little hose on the end that gets fed fuel from the carb body. Then I pinch it with my fingers over and over pushing the plunger in and out until it starts squirting fuel out of the end that feeds the brass injectors on either carb. Sometimes you have to hold your finger over one side or the other while you pump to get it primed.

I stick a little piece of primer line on those injectors(3/32") and then I can put the little straw from a carb cleaner can in that and spray to confirm that those little brass fittings(what I've been calling "injectors" are not plugged up. Many times they are.

If you pull a set of carbs with a working pump then you can get about 2 more squirts out of it before the fuel dries up. I look for this when I first pull them to know if I have to fool with the accel pump or not. Personally I've had trouble with reviving them when they are out so I'll put on a known good one or re-jet the carbs(larger low speed jets) so the ski runs right without one.

 

[ape1972]

Awesome! Thanks for the help! Ill check into the accel pump right away. Any other help or tips are greatly appreciated.

 

[dieselndoo]

I use compressed air to rid the debris from the fittings. If still plugged, then v is a lighter.
I'm in orange county if you have issues, bud

 

[ape1972]

Thank you all for your suggestions! I will try all of them and let you know the results.

 

[etemplet]

I'm an old two stroke guy.... have to hear it run. LOL

 

[ape1972]

Okay everybody!
I pulled the carbs yesterday. When i pushed the accelerator pump fuel trickled out of one but not the carb close to the Mag. I pulled the pressed brass elbow from the carb to clean it out and there was something obstructing it. I proceeded to the other carb and the brass elbow snapped at the carb. I had to drill out the busted piece and found that inlet to be very clogged. My question is where can I find the brass elbow??? It had a ball inside so I assume its a check valve and is needed. please help!!!

 

[Chester]

Not available, don't pull them out.

Chester

 

[ape1972]

Update!

I just got back from Lake Nacimiento last Sunday. I cleaned out the accelerator pump and fittings. They were completely free of debris. The ski ran much better but still had to feather the throttle a bit. Also when I would ease off the throttle it would bog down then would have to feather again. The other problem was when I had a passenger or choppy water it would magnify the problem. As always any help is greatly appreciated.

Adrian

 

[Mickirig1]

You have to figure the accelerator diaphragms are how old? You did replace the little rectangular low speed check valves opposite the pump section? Replaced the carb base gaskets? You did clean it well and get all the little low speed holes to flow? Try the pull the choke test when it bogs at low speed? Dies it's rich,goes it's lean. Check fuel system for leaks? Repair manuals are available free off the Internet if you do not have one. Sometimes no matter what you do you have to replace the carbs.

My knowledge is from single carb ski's. So if I am off track, ignore me.

 

[ape1972]

Hello and thanks for the reply...
The main pump diaphragm and secondary accelerator pump diaphragm are good. I did choke the ski and it ran worse (died quicker). No fuel leaks that I can smell or see. Should I vacuum test the fuel lines?

 

[Mickirig1]

You read the top of forum sticky on carb adjustments? It has a great lecture on carbs and rebuilding. Read these:
http://www.seadoosource.com/mikunitests.html --- http://www.groupk.com/tec-carbs98.htm
If you put a hole in the little rubber valve hold down plugs on the check valves They can cause problems with fuel getting past the valve. It's possible a lower fuel pressure then needed is happening. The little low speed check valve can cause fuel load up on the low speed part of throttle. A few people have had the same problem including me.