1996 won't rev over 1/4 throttle in water. Completely rebuilt. What now?

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TurnerBFC

TurnerBFC

Active Member
Ok here we go again,

96 xp... completely rebuilt motor and carbs
-OEM Crankshaft
-CVTech Balance Shaft
-WSM Platinum 0.75mm over pistons.
-New fuel selector
-New 1/4" Fuel line all around
-New oil lines around
-Rave valves cleaned and set 3-clicks below flush at black cap

Compression is 153/152. Voltage is 13.6 volts with brand new OEM Rectifier.

Problem: Ski won't rev over 1/4 throttle in the water. Out of the water, I rev it and hold it full throttle... it will climb to full throttle and then begin to die down.

Help? ��

CAUSE OF PROBLEM FOUND: SEE POST #2,49,51
 
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Matt Braley said:
Broken baffle in the waterbox clogging the flow perhaps.
Click to expand...

I really think it's a fuel starvation problem but to check this, what would be the best way. Remove the waterbox and shake it to listen for a rattle?

Thanks Matt, you've helped me fix a problem before
 
Out of the water will tell you nothing except that it runs.
Rotary valve timing?
Did you pressure test the engine? Pressure test the fuel system?
 
mikidymac said:
Out of the water will tell you nothing except that it runs.
Rotary valve timing?
Did you pressure test the engine? Pressure test the fuel system?
Click to expand...

It's at my cottage now with me. I will get a video and send upload it. I think that will help you guys to help me.

Engine wasn't pressure tested or fuel system. Rotary valve was timed as per the service manual. I'm really lost after rebuilding most of the ski
 
Yes you would pull it and shake it. You might need to hold off on that though until you get all the basics shored up. Those carbs can't be trusted to feed an engine correctly if all the steps in the carb sticky were not followed. A pop off tester is a must.

Picks and/or video would be good. I'd like to see fuel line routing and such.
 
Matt Braley said:
Yes you would pull it and shake it. You might need to hold off on that though until you get all the basics shored up. Those carbs can't be trusted to feed an engine correctly if all the steps in the carb sticky were not followed. A pop off tester is a must.

Picks and/or video would be good. I'd like to see fuel line routing and such.
Click to expand...

I found the carb rebuild PDF. I'm going to take them out and follow that intensively to ensure I've placed all gaskets and diaphragms in the correct spots.

I'm also at the cottage and don't have a tester... my own fault.
 
Carb and or fuel issues. With all that smoke you are rich at idle too.
What carb kits and needle and seats did you use? What springs did you use?
 
mikidymac said:
Carb and or fuel issues. With all that smoke you are rich at idle too.
What carb kits and needle and seats did you use? What springs did you use?
Click to expand...

This motor is brand new. Running premix (660ml of XPS in tank) and oil injection. I used genuine Mikuni kits and left the springs alone. Also used new 1.5 needle and seats.

Is there a chance I rebuilt them wrong?
 
Sure there is. I'd go through them again making sure you've used the right stuff in the right places. There are a lot of gaskets left over when your done.
 
Carbs are coming out now as we speak. Will report what I find. Can anyone tell me the pump side gasket/diaphragm sequence?
 
Can someone guide me to the diaphragms that go in the pump (MAG) carb? I have black, clear, black... and for the PTO Carb where the little filter is, I have the oring, fuel filter, and the thin flexible black diaphragm?

Is this correct?
 
No no no.

From the mag (pump) carb body......
1 filter
2 Spaghetti gasket
3 black diaphragm WITH THE SMALL TRIANGLE!! This is a common mistake. I don't know why they include that other black one in the kits with the larger triangle shaped hole that goes outside the spaghetti gasket. The fuel will not flow right with that one it must be for other brand skis or something.
4 pump block. I leave the round plastic circles in there unless they are real bad.
5 round O-ring
6 clear plastic diaphragm
7 black outer gasket
8 pump cover

On the rear
1 filter
2 Spaghetti gasket
3 cover

that's it.
 
Matt Braley said:
No no no.

From the mag (pump) carb body......
1 filter
2 Spaghetti gasket
3 black diaphragm WITH THE SMALL TRIANGLE!! This is a common mistake. I don't know why they include that other black one in the kits with the larger triangle shaped hole that goes outside the spaghetti gasket. The fuel will not flow right with that one it must be for other brand skis or something.
4 pump block. I leave the round plastic circles in there unless they are real bad.
5 round O-ring
6 clear plastic diaphragm
7 black outer gasket
8 pump cover

On the rear
1 filter
2 Spaghetti gasket
3 cover

that's it.
Click to expand...

That is beyond helpful. I will remove the one black one, check the soft black one for the triangle size, and fix the rear PTO carb. I'm enroute to buy the parts to make a pop-off tester.

Will report back in a few hours. Thanks again Matt
 
Matt Braley said:
No no no.

From the mag (pump) carb body......
1 filter
2 Spaghetti gasket
3 black diaphragm WITH THE SMALL TRIANGLE!! This is a common mistake. I don't know why they include that other black one in the kits with the larger triangle shaped hole that goes outside the spaghetti gasket. The fuel will not flow right with that one it must be for other brand skis or something.
4 pump block. I leave the round plastic circles in there unless they are real bad.
5 round O-ring
6 clear plastic diaphragm
7 black outer gasket
8 pump cover

On the rear
1 filter
2 Spaghetti gasket
3 cover

that's it.
Click to expand...

So this is the correct gasket to use on the mag carb? (THE ONE ON THE BOTTOM RIGHT) I have to open it up and check which one I installed when I get back to the cottage.

https://www.picclickimg.com/d/l400/...kuni-Sbn-Super-Bn-Carb-Carburetor-Rebuild.jpg
 
That's correct. That other one like it has no place in a Seadoo. It should be ignored like the included springs.

HS needles closed
Low speed needles 1 1/4 out
pop off 30ish (high 20's to mid 30's should be fine) just have them the same
get carb cleaner with a straw and blow those carb bodies out through the low speed jet.
make sure the oval clear plastic pieces are stuck to the bottom of the kidneys and not peeling up at all
use your pop off tester to test your fuel supply by blocking where it feeds the carbs and pumping from the ON hose you yank off the baffle. This will confirm that the fuel valve, O-ring on top of the filter bowl, hose connections, etc. are not leaking and drawing air in. It should hold 5 psi without visibly leaking down.
 
I unplugged the red wire from the Rectifier as a test, and still no difference. It feels like the ignition is cutting out. The ski starts and idles fine but once I try to get going, it starts to cut out and big/surge.
 
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