My 1st ski. 1999 SPX Hard to start, dies at idle, hesitates on acceleration from idle.

[Suprallen]

1999 SPX new prop, wear ring. 145 psi compression, goes to 150 if you stop cranking and turn it over again. Hard to start, dies at idle, hesitates on accel from idle. Runs 50 mph on GPS with 240lb of me on it pulls hard "I have nothing to base this on never have been on a ski before" in my opinion after it gets going. Turned idle up to 5mph GPS will be ok for 30 sec then gets rough and dies. Hard to start. On tear down found one choke plate still 30 % closed when other one all the way open. Both set screws for choke plates tight. Found carbs do not open 100 percent 95 or 97 was all. Had 1/16 to 1/8 inch of cable 10 mm nuts adjustment to full throttle. Found fuel leaking at one way valve for acceleration pump. Found carb with fuel pump missing rubber damper gasket, sheet of soft rubber on top of o ring style damper gasket. number 5a on mk-bn/44 spr Mikuni rebuild kit paper list in kit. Low speed screw 1 1/2 half out high speed screw 1/8 out. Had short springs in pop off valves. Repaired small leaking fuel lines from accel pump through one way valve to carbs. Installed new Mikuni kits and needles and seats. Used short springs like in carbs when I tore them down. Pop off pressure for carb with fuel pump was 26PSI spec is 36 to 40. Installed long spring pop off was 45PSI. Cut just tight coils off, was 36PSI. Short spring in carb with accel pump on outside had 20PSI pop off, 36 with long spring. Any reason not to set springs to 36PSI? Pop off pressure was set very low by shop that built carbs 2 seasons ago any reason why? Has only been ridden 4 times since carb overhaul. Questions does a 1999 SPX super bn38 with only one paper gasket and 2 o ring style gaskets on fuel pump have a damper diaphragm gasket on cavity of fuel pump? It is listed on parts of carb online for a 1999 SPX. What are pros, cons of not using one? I did install one. Obviously carbs need to open 100% what top speed is expected of such a ski in top shape with 240 lb rider? Accel pump leaking fuel and sucking air was most likely my hard start and hard to get going? Carbs looked clean what else might make it die at idle? Any reason to adjust choke plate to not open 100 percent? Will have back in water this weekend. Thanks for any input guys.

 

[Suprallen]

And all fuel lines were replaced 2 seasons ago.

 

[JeremyD615]

You just need to get your carbs sorted... The choke plates need to be synchronized, which means you should check the throttle blades as well. I would say someone did a bit of a hack job when they overhauled the carbs last time...

First, check your o ring on the water separator. If it’s even questionable, replace it.

Next, check your fuel selector. If you don’t know when it was replaced last, I’d go ahead and put a new one in. Don’t try to clean it, as the solvents tend to dry out the seals and make them worse.

Then take your carbs all the way back down and double check to be sure they are clean and clear. Follow the carb rebuild sticky on the top of this forum to go through them again.

You’re going to need to order new springs. You should never cut or stretch the springs on the carbs. If you have to make a small adjustment, you need to do it with the lever rather than the spring.

 

[Suprallen]

And choke cable would not stay pulled out. Installed a primer kit. Is it best to get fuel from reserve line as per instructions, or from return line before restriction. Where is restriction on return line?

 

[Suprallen]

You just need to get your carbs sorted... The choke plates need to be synchronized, which means you should check the throttle blades as well. I would say someone did a bit of a hack job when they overhauled the carbs last time...

First, check your o ring on the water separator. If it’s even questionable, replace it.

Next, check your fuel selector. If you don’t know when it was replaced last, I’d go ahead and put a new one in. Don’t try to clean it, as the solvents tend to dry out the seals and make them worse.

Then take your carbs all the way back down and double check to be sure they are clean and clear. Follow the carb rebuild sticky on the top of this forum to go through them again.

You’re going to need to order new springs. You should never cut or stretch the springs on the carbs. If you have to make a small adjustment, you need to do it with the lever rather than the spring.

 

[Suprallen]

Will replace o ring on water separator, and replace fuel selector. Installed primer kit as choke cable would not stay out. Have old sync tool for carbs some where will check flow of both at idle. So bend metal lever dont cut springs will do. Any reason to use short springs with 20 to 26 PSI of pop off? Best to set to 36PSI or 40? Thanks

 

[POPPS]

And choke cable would not stay pulled out. Installed a primer kit. Is it best to get fuel from reserve line as per instructions, or from return line before restriction. Where is restriction on return line?

I run my return line at the lowest point in the hull, and from there T my primer line, ,this way there will always be fuel for the primer to draw from.

 

[mikidymac]

The choke shouldn’t stay out. It should spring back when you let it go.

You need to order the correct 95 gram springs, the ones in the kit are wrong.

The primer is fine too be installed in the return or the reserve line.

 

[mikidymac]

I run my return line at the lowest point in the hull, and from there T my primer line, ,this way there will always be fuel for the primer to draw from.

This is also great because if the primer fails which isn’t uncommon your carbs won’t be sucking air and run lean.

 

[Suprallen]

This is also great because if the primer fails which isn’t uncommon your carbs won’t be sucking air and run lean.

Thanks