Super Jet Still Bogging... it can't be the carb....

swapmeet

swapmeet

Brotastic
Location
Arlington TX
Alright ya'll....

I've tried so many variations of carb tuning, including trying a buddy's carb.

It feels like what I believe is a low end bog. I've used a variety of low jets and low speed screw settings.
I can't even recall but its been everything from a 130 to a 112.5.
None of this has solved the issue, the only result is that if I turn the low screw down too tight with too small a jet it won't idle...

Engine:
701, hammer porting GroupK
Protec head, 155 &160 psi 37 cc domes I think.
MSD (not total loss)
B-pipe

Currently the carb is set up as:
120
147.5
1.5 N&S (i've tried a 2.0)
115 spring (dull silver correct?)




Here are some other items of note, not sure if this matters but lets discuss.
  • I'm running two wear rings. It creates a larger cavity of water before the prop, pushes the nozzle and prop 3" farther back.
  • Scat 11/17 swirl prop, no cut back
FWIW it runs slightly better cold than hot. As I ride longer and longer, this problem gets slightly worse. I would say 25% maybe?

I took some video today. My gopro ran out of batteries, of course, but I got a little video of what its doing,
But maybe you can watch and listen to this and help me out.
Its starts right as I got out of the no wake zone. If you watch my finger and listen/ watch the acceleration, its delayed.
Also, if you keep it pinned it hits like a light switch. Its almost unmanageable how hard the power band hits after it clears what feels like the bog.
It bogged great right as the gopro died. The youtube video cuts it off worse.


Anybody have any suggestions?

*edit* the lag on youtube doesn't help my situation... hopefully you can hear it at the end and understand what i'm talking about.
 
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dragginblazer

dragginblazer

Do Good Jetski Crew
Location
North Richland Hills, TX
I've ridden it. Bogs down low really bad but once at mid rpms it takes off like a rocketship leaping out of the water. I even loaned him a carb off my running ski to verify it wasn't a carb issue. I'm thinking its an electrical issue.
 
swapmeet

swapmeet

Brotastic
Location
Arlington TX
To Matt and Jump on it.

The engine came out of a FX1 with a stock 122mm pump and I believe a stock prop. At that time the engine overpowered the prop, and just cavitated horribly. So to answer your question directly, it seemed to run fine with the exception that it overpowered the prop.
I've only run it with the extra wear ring.

Good questions, and something i've been thinking about.

The engine is now in a FX1 with a 144 pump conversion, plus the wear ring.
My drive shaft is a custom length, but I think I have a stock SJ shaft laying around... i've debated about pulling the extra ring and trying it in a standard/stock configuration but its a great deal of work to swap shafts on a hunch.

Dragginblazer and I have made a lot of assumptions and have some ideas, but they're all just guesses. I hate just stabbing at a problem hoping that something works.
Thats why i'm asking on here, hoping for some direction.

Could it be timing? where its not advancing at the right time or its too advanced? I don't know a great deal about timing, so I could be talking out my butt here.
 
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Waternut

Waternut

Customizing addict
Location
Macon, GA
Can you run a standard pump in that hull now? If so, just try your buddies pump and see if the problem goes away.

FYI, dull silver is 95g and shiny silver is 65g...

You say it gets worse as the day goes on? Do you have or can you borrow a spare coil? When a coil is going out, it sucks nuts in the low rpms regardless of throttle input and cleans up nicely around mid rpms. The coil also gets progressively worse the longer you run it. Although, with the coil problem, it typically rips hard for a few minutes and then tanks. However, it sounds like you're still figuring out the carb settings and if you're way off, it may be a carb issue at first and then a coil problem later making things really confusing.
 
swapmeet

swapmeet

Brotastic
Location
Arlington TX
I got my buddies pump, the prop is beat to hell, but I should give me an indication.

That's interesting info about the coil. It's hasn't tanked yet, but everything else is spot on as far as your description.
I think one of us has a spare Coil laying around so if we can find it I'll give that a shot as well.

What about grounds?
 
Waternut

Waternut

Customizing addict
Location
Macon, GA
swapmeet said:
What about grounds?
Click to expand...

Unlikely but possible I guess. Usually a grounding issue causes no spark or intermittent spark with random shutdowns and/or random bogs that clear up. I assume you have changed spark plugs but if not, it's only a couple bucks and eliminates one source of trouble.
 
swapmeet

swapmeet

Brotastic
Location
Arlington TX
Ok, just finished changing everything on the pump. That was a massive undertaking, the mounting holes arn't set up for a stock length shaft.
I had to cut down a almost stock length shaft by an inch and then re-spline it by hand. Painstaking stuff.
Then I had to make a steering adapter... long story... Anyhow, about to go to the lake. The whole time I was pulling the prop, swapping the bearings, cutting the splines I kept thinking "this can't be the problem..."

I guess we'll see. I'll try running it with the hood off to test the exhaust leak idea. My ski's so sketchy i'm scared of running w/o a hood but if it fixes this then i'll suck it up and try not to fall.
 
swapmeet

swapmeet

Brotastic
Location
Arlington TX
No improvement......

Ok, rode with the normal pump config, same results, although during one test it tried to die, so I suspected lean bog. I put in a 122.5 and opened up the low speed screw half a turn. Still bogged.

Rode with the hood off, no change except it was loud. I did notice that I had quite a few air bubbles in the fuel return line, and a few in the fuel inlet line. I'm not running a selector switch. So not sure if the bubbles mean anything.

Last thing I notice, and forgot to mention, I get a lot of oil on the surface of the water coming from my exhaust when the ski is sitting.
I have a flow control to my stinger but when im done riding I dont have any water to clear out of my exhaust.
 
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swapmeet

swapmeet

Brotastic
Location
Arlington TX
I have no idea about the spark. I have a tool to check it, but from what I've read if the engine isnt under load it's not an accurate representation.

Anybody have a link to a Coil testing proceedure?
 
swapmeet

swapmeet

Brotastic
Location
Arlington TX
I'll check the spark. WAB, I've had the reeds out recently and they looked fine.
I've had this problem since I put this motor in this hull.
 
Y

yigaljet

Location
israel
hello
it sound like pop off circuit is way off
1.check your fuel tank for tightness ,every time you open the cover you should here a hissing sound (there should be prussure),if not, the one way check valve is malfunction
2 check your oem fuel filter is it 3/4 full or allmost full,this is a good indication for tank under pressure
3 do you run b pipe did you open the upper screw
4 your pop off should be 17-20 psi (are you running single)
5 is the engine over reving outside the water when you hit the throtle ?(air leak)
 
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