2000 superjet fuel starvation

[cgeertg]

I recently purchased a used 2000 superjet, which on the second ride had trouble with the motor stalling out when accelerating from low-mid range rpm's. To get it started again, I would pump the primer (previous owner installed) and get back to plane, then it would die down again. This ski was stored (indoors) for over a year, the carbs had been adjusted for higher elevation riding for which I have set the adjustment back to the supposedly "marked" stock setting. Any suggestion on where to start? hard to tell if the primer system is installed correctly, nothing to compare it with. Seems to be starving for fuel?

Suggestion appreciated!!

Thanks
Chris

[Bryan Glynn]

Well, is it slowly stalling out, or quickly stalling - as in siezing? My first suggestion is to rebuild the carbs - you cannot know what you are dealing with in a case like this, and if you have clogged internal filter or gummed up diaphragms, you will be tuning till the cows come home for nothing. After rebuildint the carbs, set the needles back to stock specs, which are 5/8th turn out on the lows, and 5/8ths turn out for the #1 high, and 1 1/8th turn out #2 high. The jets should be 67.5 pilots, and 120 #1 main, 130 #2 main.

I would bet that going back to stock specs, assuming the rest is stock, will solve your problems.

[cgeertg]

The stalling is rapid, like running out of gas, no mechanical "freezing" taking place as far as I can tell. Once stalled, a couple of pumps on the primer and it starts right back up. To clarify your suggestion, do you reccommend just cleaning? or purchasing two rebuild kits? These gaskets are most likely not re-usable, so I guess this means time to order parts. Let me know what you think. Thanks for the quick response and the settings!!

Chris

[Wet Wolf]

have there been any mods done to the motor?

[cgeertg]

No modifications to the motor, just the removal of the butterfly choke and addition of the primer system. Not much trust in the person installing the primer, the fuel on/off/reserve is upside down!! so the "reserve" and "on" positions are reversed. This should not be the reason for lack of fuel due to the fact that the tank is 3/4 full at failure. I would like to re-assemble it correctly though, just need to install the three position valve rotated 180 degrees.

[Bryan Glynn]

Rebuilding IS 'cleaning'. Make sure everything is to spec when you are in there. No, the gaskets are not reuseable - that's what comes int he rebuild kit. Download the rebuild instructions in the Tech section to see exactly how to do it.

[97GP1200]

Is there not a pressure relief valve in that tank? Was it hot outside where you where having problems? That would be the simplest thing to check first.

[Bryan Glynn]

To easily test that, just disconnect the vent line from the top of the tank and take it for a spin. This condition will typically not appear until the ski has been run for several minutes, however, as it takes time for the vaccuum to develop in the tank.

[ February 04, 2002, 07:17 PM: Message edited by: Bryan Glynn ]

[cgeertg]

Thanks Bryan, I will get the gasket kits and clean/inspect the internals to spec.

To answer 97GP1200, the weather was cold, in fact around 40 deg, water temp at 44 deg. Yeah I had on a drysuit, not too bad though!! As far as the pressure relief valve, I am not sure.

All, I appreciate the quick and helpful response!! My first time at SBT forum. Seems to be a good thing going here. I will let you all know what happens.

Thanks
Chris

[cgeertg]

I took the line off the top of the fuel tank that travels to the water separator, then to the handle pole. Instantly I heard the sound of air, as it turns out the it was negative pressure or vacuum in the fuel tank. Seems to make sense that this would limit the ability of the diaphram to pump from the tank. Is there a relief valve? How do I test this disconnected line for proper function? I can not blow air though it. Is this normal?

Chris

[Bryan Glynn]

Right at the end of that line where it attaches to the tank is the check valve. You should be able to blow to the tank through it. If not replace the valve.

[cgeertg]

As it turned out, the check valve was working properly but the water seperator was not allowing air through in either direction. Since it is rivoted to the hull, troubleshooting this was not fun. What I found was some epoxy or glue in the output of the water seperator. This was most likely there from date of manufacture, since this epoxy was also on the outside of the seperator. Once the line was open again, the fuel starvation problem went away. Might have to take to the shop to get this replaced since there is residue from the clog in the water seperator internals now.

Thanks again for pointing me in the right direction.

Chris