Super Jet Starting to get aggravated

[lazyt747]

Every time I take this thing out I spend the entire time trying to get it to run correctly.

Yesterday I did so many carb adjustments it could make your head spin. Towards the end of the day we finally seemed to get it correctly dialed in but keep having one problem - I'll be running and it seems to run fine at about half throttle - full throttle on flat water when I keep the ski in a steady position, but as soon as I jump it a bit and gun the throttle to pull out it hesitates like crazy and doesn't want to go. It seems to happen mostly when I am hitting wakes (big or small) or anytime the ski goes from a higher speed to a dead stop. Once I hit the throttle full on to pull out of a landing and/or take off it hesitates terribly. WTFFFFFFFFFFFFFFFFFFFFFFFFFF.

What is the problem?????!?!??!>#3rlkqwpefjqoiejwfoiwjhegfoiju10392riu[10u3

 

[Bobert540]

You may want to post up you motor/pump/prop setup. Be as detailed as possible, there could be many factors but not knowing any of that its hard to have a baseline to help.

 

[Magyar68]

For me this would happen at around half a Tank of gas. I extended both fuel pickups to the bottom of the Tank. Used a Y connector on the 2 Fuel lines and bypassed the Selector switch. At half a tank of gas when bouncing around the main pickup would go dry, and it would either Die, or I wold have to feather the gas to keep it going.

 

[dmpus]

+1, try to ride on reserve and see if runs better

 

[Fro Diesel]

Is the overheat sensor wires shorting out in ebox?

sent from Fro Diesel using tapatalk2

 

[lazyt747]

You may want to post up you motor/pump/prop setup. Be as detailed as possible, there could be many factors but not knowing any of that its hard to have a baseline to help.

705 bore on a 61x cylinder block
ADA 35 cc head (~180 PSI)
Factory Mod B-pipe
Stock 38 62t carbs
- Needle/seat 1.5
- Hi 135
- Lo 75

For me this would happen at around half a Tank of gas. I extended both fuel pickups to the bottom of the Tank. Used a Y connector on the 2 Fuel lines and bypassed the Selector switch. At half a tank of gas when bouncing around the main pickup would go dry, and it would either Die, or I wold have to feather the gas to keep it going.

I was thinking that it might be the fuel pickup. I'm all stock right now with the reserve knob taken off. I was wondering maybe when the tank gets shaken that I get air in my lines somehow. I think I'm going to pull the pickup out and see how it looks today.

+1, try to ride on reserve and see if runs better

It has no reserve switch.

Is the overheat sensor wires shorting out in ebox?

sent from Fro Diesel using tapatalk2

The overheating sensor was taken off from the previous owner with the new head install. I checked in the ebox before I put a new coil in and noticed the loose wire. This sounds really interesting, how are you supposed to properly disconnect the temp sensor from the box? Might double check to see that it was done correctly as well.

 

[lazyt747]

Also, the previous owner told me that the waterbox had an issue. When I looked at it the box had a couple missing rivets. I put two new rivets in and put the box in the ski. Any possibility that the waterbox could have internal issues that would cause this problem?

 

[schicks]

do you have the stock cdi in there?

 

[swapmeet]

Maybe minor exhaust leak? Is your fuel system staying pressurized?

 

[Big Kahuna]

remove you plug caps, take needle nose pliers and tug on the wires, if some pull out, cut the wires back and tug again, if it does not pull any wires, put your plug caps back on. Sounds like broken strands in your plug wires.

 

[Matt_E]

Things to check:

Your rubber exhaust tube may be blocking the pressure reference holes on the carb diaphragm cover(s). Most of the time it may be fine, but during jumps it might move around enough to block those holes. Check that.
Your fuel lines may have holes or splits in them.
Your needle & seat may be worn.
Fuel tank vent.

 

[lazyt747]

do you have the stock cdi in there?

The previous owner told me he changed that out with a stock one before figuring out it needed a new coil.

 

[lazyt747]

Maybe minor exhaust leak? Is your fuel system staying pressurized?

I am not sure. I am thinking that maybe it could be from the waterbox but I can't see it leaking. I drilled out many of the rivets and replaced them as well as sealed them.

Also, the factory mod b-pipe is brand new.

remove you plug caps, take needle nose pliers and tug on the wires, if some pull out, cut the wires back and tug again, if it does not pull any wires, put your plug caps back on. Sounds like broken strands in your plug wires.

The coil is brand new (MSD Coil). Plugs and wire should have great connection.

Things to check:

Your rubber exhaust tube may be blocking the pressure reference holes on the carb diaphragm cover(s). Most of the time it may be fine, but during jumps it might move around enough to block those holes. Check that.
Your fuel lines may have holes or splits in them.
Your needle & seat may be worn.
Fuel tank vent.

I made sure to turn the rubber exhaust tube the other day and tighten it so that it is bumped against the fiiberglass and as far away from the carbs as possible.

The fuel lines are all brand new besides what it in the fuel pick up.

There is a possibility that the needle and seat could be worn, if nothing else I am going to send the carbs out to JSS to have them rebuilt.

Ordering a new fuel tank vent now. A buddy of mine explained to me the pressure necessary in the tank to send fuel to the carbs.


Thanks for all of the advice guys.



Also, just out of curiosity, would it be worth putting a different set of carbs on this thing with my mods or would it just be excessive and more of a waste of money?

 

[aramis]

x2 on everything that has been suggested so far...a few more ideas:

what is the pop-off pressure, and how many turns on the lo/hi screws?

was the coil replaced with a stock one or the POS MSD red one?

the coupler cover is installed, right?

If you think the waterbox had issues, check that thoroughly...a loose baffle can cause all sorts of weird things.

 

[lazyt747]

x2 on everything that has been suggested so far...a few more ideas:

what is the pop-off pressure, and how many turns on the lo/hi screws?

was the coil replaced with a stock one or the POS MSD red one?

the coupler cover is installed, right?

If you think the waterbox had issues, check that thoroughly...a loose baffle can cause all sorts of weird things.

I can't check the pop-off unfortunately because I do not have a guage. I have been absolutely everywhere with the hi's and lo's. The lo has typically been at about 1 turn out and the hi's have been anywhere from 1-1.5 turn out.

The coil was replaced with an MSD (I know, should have went with a JSS but I already had it ordered).

What exactly do you mean by coupler cover?

I shook the waterbox and even blew air through it, seems solid.

 

[QJS]

If you have rivets in the waterbox its a flatnose with a fibreglass waterbox?? I would suggest you remove it and give it a good shake to see if a baffle has come loose.
Chris.

Also, the previous owner told me that the waterbox had an issue. When I looked at it the box had a couple missing rivets. I put two new rivets in and put the box in the ski. Any possibility that the waterbox could have internal issues that would cause this problem?

 

[lazyt747]

If you have rivets in the waterbox its a flatnose with a fibreglass waterbox?? I would suggest you remove it and give it a good shake to see if a baffle has come loose.
Chris.

Hey Chris,

I shook all of the drilled rivets out of the waterbox and even without the rivets that I had taken out the baffle remained solid and didn't shake/rattle at all. Everything was sound so I riveted it back together and threw it back in. If it had a bad baffle, wouldn't you be able to feel it/hear it move around when the waterbox is shaken?

 

[Matt_E]

Don't send your carb(s) off to get rebuilt. Anyone capable of taking a chit without smelling for hours afterwards can rebuild a carb.

 

[lazyt747]

Don't send your carb(s) off to get rebuilt. Anyone capable of taking a chit without smelling for hours afterwards can rebuild a carb.

I want to do it myself of course but the needle on one carb and the seat on the other have stripped heads on them and I cannot get them out. The way I found the sizes was through pulling the opposite seats/needles. They actually looked fairly clean as well. I just didn't want to mess up the carbs somehow trying to take those stripped screws out. The previous owner definitely did a number rounding bolts out.

I am just more curious to see if there would be a worthwhile performance increase or not. I have a feeling it wouldn't.

 

[Matt_E]

Those are very soft screws. Drill them and use an ez-out.