Superjet issue

[RivMan]

Hey guys

Finally got my new ski out on the water today, and left not so happy.

The current setup is:
94 SN
61x/61x
B-Pipe
Jet maniac porting
Ada head (175/175 psi)
Blackjack 44
Hooker 9/15

The ski ran like a dream for about 45 mins. Plenty of power, nice throttle response, pipe not too hot, ect.

After 45 mins or so, the ski started bogging down under throttle. About 2 mins after I first started noticing the bog, I couldn't touch the throttle more then about 5%. The ski idled perfectly, and would run perfectly just over idle, but any more throttle then that, it would bog down, and stalled several times.

I checked the temps (all fine, pipe cold), compression (175/175), no exhaust or fuel leaks that I can see, nothing under the good that seems out of the ordinary.

Any ideas?

Thanks
-Rob

 

[Half flip95]

water getting into cyl?

 

[RivMan]

Pulled both plugs, and they're both black and wet, smell like fuel. Compression is still even and 175.

I'm thinking more of an ignition issue.

-Rob

 

[Harbor]

Fuel tank venting ok, no vacuum is developing in tank when fuel is consumed?

Any secondary ignition misfires noted or just flat boogggggg booooggggg when throttle is open past 5%

Have you run that ignition set up you have before with success ?

Got any ignition parts to swap with, Cdi, coil, stator......

Ignition timing good, broke a stator mounting bolt on a ski last summer it broke one of the stator coils and caused a bog

Had a lot in the past the coil wires break inside right at the plug cap and causes a sharp misfire

Also your running resistor spark plugs and plug caps, had non resistor plugs cause power loss after 45 minutes of riding, the more I rode the worse it got. Emf frequency caused Cdi to go wakoo, never got as bad as your reporting though. Just a heads up

Had a needle sticking in carb last year, it completely stuck shut and cut fuel off in my case

Fuel pump working, Return line free of obstructions and clear?

Exhaust path clear, no broken baffles in water box or collapsed exhaust hoses or exhaust hoses swollen on the inside ?

Cranking spark test, how's the spark look, bright yellow or weak thin blue,

Both cylinders firing ?

 

[reidfrombj]

Does it rev up past 5 percent throttle out of the water on the trailer? Check your fuel filters, maybe you sucked up some stuff in the bottom of the tank.

 

[RivMan]

Lots of good stuff here, I'll try to address what I've checked!

Fuel tank venting ok, no vacuum is developing in tank when fuel is consumed?

Checked this, pulled the cap off and didn't notice any pressure change. I don't think this is the issue.

Any secondary ignition misfires noted or just flat boogggggg booooggggg when throttle is open past 5%

More of just a flat booooooooog. I didn't hold the throttle long while it was bogging (Didn't want a lean condition sending my engine packing for the season). It comes on aggressively though, stalls out without too much effort.

Have you run that ignition set up you have before with success ?

No, this is a new to me ski, and the former owner didn't really ride it (Built it as a spare for his WCF Vision)

Got any ignition parts to swap with, Cdi, coil, stator......

I don't have any spare Yami parts around, I'm trying to source some locally

Ignition timing good, broke a stator mounting bolt on a ski last summer it broke one of the stator coils and caused a bog

Not sure on this one. How would I check timing on this motor? It starts and runs properly (Like it did all day), so I don't think timing could have shifted very much.

Had a lot in the past the coil wires break inside right at the plug cap and causes a sharp misfire

I'll take a look at this. I have a little slack in the plug wires, so I'll cut them back a half inch.

Also your running resistor spark plugs and plug caps, had non resistor plugs cause power loss after 45 minutes of riding, the more I rode the worse it got. Emf frequency caused Cdi to go wakoo, never got as bad as your reporting though. Just a heads up

I'm running a pair of BR8ES plugs that were installed in the ski when I bought it. I plan to replace them and test again this evening.

Had a needle sticking in carb last year, it completely stuck shut and cut fuel off in my case

The carb is a recently rebuilt Blackjack, with a new needle and seat. I'll test the popoff pressure, but it was 16psi a couple weeks ago when I put the ski together.

Fuel pump working, Return line free of obstructions and clear?

All new lines, I'll take a look at them though.

Exhaust path clear, no broken baffles in water box or collapsed exhaust hoses or exhaust hoses swollen on the inside ?

All the hoses look ok. Stock SN waterbox, so I'm not sure what's in there for baffles. I don't hear any rattling or odd exhaust noises at idle though.

Cranking spark test, how's the spark look, bright yellow or weak thin blue, Both cylinders firing ?

I'll test this tonight

Does it rev up past 5 percent throttle out of the water on the trailer? Check your fuel filters, maybe you sucked up some stuff in the bottom of the tank.

It fires up and runs / revs just fine on the trailer. No odd noises or anything

Thanks guys!
-Rob

 

[modularjunk]

needle and seat is stuck it sounds like New needles n seats get stuck sometimes until they break in. I rebuilt my carb 5 tanks through it then it would start idle but not rev n then die pulled the carb at the ramp and needle was stuck. Pulled it out with pliers cleaned up the sides with little emory cloth and ski ran perfect

edit** i just saw your prev post that it runs normal on the trailer sounds like maybe a bad ground issue/ electrical

 

[Fro Diesel]

Take the carb off and check the internal filter. My ski just did the same thing.


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[Fro Diesel]

Just bc it revs on the trailer doesnt mean it will rev with a load on the pump

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[Harbor]

Take the carb off and check the internal filter. My ski just did the same thing.


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Yup add this to the list, the little coned screen filter like to catch lint, drip particles, paint flakes and debri

 

[RivMan]

Will do

The carb is orientated in such a way that I can pull the pump pretty easily. I've got a couple new filters sitting here too.

-Rob

 

[RivMan]

Well I think I found the problem. Heh

Thanks guys!

-Rob

 

[Harbor]

That looks like more than it can hold damn, might check your tank or be prepared for a plug up again

Nice work

Take the carb off and check the internal filter. My ski just did the same thing.


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[amitchell]

Is that from a paper element filter giving up? Or just general crud?

 

[JetManiac]

Well I think I found the problem. Heh

Thanks guys!

-Rob

That is the most clogged filter I have ever seen! How did that get in a freshly rebuilt carb?

 

[RivMan]

I guess it was all crud from the tank. I didn't use an inline filter when I re-plumbed the ski. Just added one though!

 

[amitchell]

Looks like you were storing the wifes shower hair in the tank during the off season.

 

[imabadfish]

ha that's a crazy amount of dirt... I did clean that carb before putting on the motor, but I did not clean the tank. I'll add that to my to do list though.. and keep my wife out of the garage.