Super Jet Bogs on bottom and gets worse as you ride

I'm at my wits end with this superjet. It's a 92 with a 701 with the 6m6 bottom end. I just did a complete rebuild and it does the same thing it did before. When you take it out it runs awsome with a tiny bit of bog on the bottom. But as you ride it gets worse and worse. Until it amost in rideable. Take it to shore play with the carb and the problem repeats its self on e back on the water.
 

Tyrant1919

Site Supporter
Location
Washington, DC
Gas tank one way valve. Make sure it lets air in.

Engine temp. Is it to hot or cold when you pull in and pull the hood.

Small exhaust leak perhaps getting into the engine compartment. Building up as you ride.
 
It's very hot to the touch when I pull it in. Where is this breather on the gas tank? It rips on the top half once it gets past that bog point and continues to rip if if you keep the revs up. But once they drop you have to get past the bog again.
 

Tyrant1919

Site Supporter
Location
Washington, DC
I don't think it's temp, but is it so hot you can't keep your hand on it, or so hot the engine block sizzles if you splash water on it.

The one way valve should be some sort of check valve off of one of the fuel lines from your gas tank. it'll be a fuel line that seems to go nowhere. You have your one or two pickup lines, your return line, then your 'breather' line with a check valve. Your gas tank may be creating a vacuum as you use gas.

Just spitballing.
 
Something I just thought of. I never changed out any of the gaskets around the reeds. They looked like they were sealed pretty good and had the gasket sealer squish out ring around them. If its not raining tomorrow im gonna take them apart and install fresh gaskets. Then head back to the lake. I've also tried riding without the hood and still the same thing.
 
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Something I just thought of. I never changed out any of the gaskets around the reeds. They looked like they were sealed pretty good and had the gasket sealer squish out ring around them. If its not raining tomorrow im gonna take them apart and install fresh gaskets. Then head back to the lake. I've also tried riding without the hood and still the same thing.
If the motor doesn't run away on you when you start the ski out of the water, then I'm sure those gaskets are fine. Could be bad gas tank valve causing the bog.

What jetting are you running in the carb?
 
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I'm running a jet kit that jetmaniac set with the parts. 145 high 115 low with a different pop spring thingy spring. Before the bog come the ski rips. And I pulled plugs and they are a nice shade of brown. So jetting is very close. Gonna try without the water separator and that valve to start eliminating things.
 
I'm running a jet kit that jetmaniac set with the parts. 145 high 115 low with a different pop spring thingy spring. Before the bog come the ski rips. And I pulled plugs and they are a nice shade of brown. So jetting is very close. Gonna try without the water separator and that valve to start eliminating things.
Removing the valve will just make it worse, your fuel tank needs some pressure. Pull the valve off and make sure blow in but not out
 

b.lee

Team Cheeseburger
Does this ski have old(er) fuel lines?
Could be pulling air into the fuel lines causing your problem... I had a ski do this once before, the more you rode it the worse it got. Bad fuel lines.
 
Does this ski have old(er) fuel lines?
Could be pulling air into the fuel lines causing your problem... I had a ski do this once before, the more you rode it the worse it got. Bad fuel lines.
The lines are newer. But when you mention air being in the lines it does have a primer bulb installed in the line. This has been there since I bought the ski. Perhaps I should take that out??? Its not needed it also has a primer into the carb installed. Im also gonna take the check valve from my 550 and swap it. If my buddy comes out with his brand new RN I want to swap his in too and try it.
 
It's very hot to the touch when I pull it in. Where is this breather on the gas tank? It rips on the top half once it gets past that bog point and continues to rip if if you keep the revs up. But once they drop you have to get past the bog again.

I have the exact same problem with mine right now its a 701 RN. Very frustrating. Mine bogged down so hard I almost lost all power. And its really hard to start in water, if I figure mine out I will let you know.
 
So I thought I had the problem solved. The ski ran perfect for about an hour. There was water in the hull I did not have a guard over the coupling and it was shooting water into the intake. Getting everything wet and making it run poorly. So yah come in for a break stuff dried it ran great again. Made sense. So i installed a guard. Rode it for about an hour and it started bogging and dying out. Thought it was out of gas. Which it almost was when I came in and checked. Filled it up went back out and now the ski just completely bogs out and has no power what so ever. It feels like the odd time like it tries to smarten up but nope back to totally bogging down. Checked the plugs they are that perfect tan brown color. So what now????
 
my blaster was missing oring on gas cap.if the ski sits in the sun for awhile it should hiss or something when loosing up the gas cap.. Right people? correct me if im wrong.:wall:
 
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ok im a newbie here so its always a process of a lmination for me whe i have problems too. A exhaust leak can cause you the problems that you are having also. Tats why i asked what kind of pipe you had if it had a coupler. {A place to leak}
 
So got some pictures of your toy? always fun to see someone elses.. I got two blasters1's. One with the casual 701 and the other someone stabbed the 760 with dual carbs. Check out my profile photos.
 

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
The 1st thing you need to do is make sure you do not have any exhaust leaks and you have spark plugs in good condition.

Next...

Make sure you tank is venting. It will run with positive pressure or 0 pressure, but it will not run in vacuum. Verify there is no water in the fuel tank. Make sure all of your fuel lines are in good condition and have a good seal around the nipple as to not suck air. Ensure your fuel petcock (if you have one) and fuel filter is clean and clear with no blockage of flow. Try riding it again...

Next...

If still problems, buy a pop-off gauge and remove your carbs. Check your pop-off before you do anything else with you carbs so you know if it was right or wrong to start. Remove all parts on the diaphragm side and clean them. Replace needle and seat if leaking (as would be seen from pop-off test) and recheck pop-off with new needle and seat. Remove adjustment screws and clean (You probably have access to your screws but if not, remove the plugs so you can access the screws). Open fuel pump side and clean thoroughly, make sure all sealing surfaces are clean, o-rings are in good repair. Remove internal fuel filter (fuel pump side) and clean or replace it. If you have any doubts about your fuel pump condition, or if you have leaking pop-off after replacing the needle and seat, then rebuild the carb using genuine mikuni rebuild kits (SBT rebuild kits are junk). Make sure you reinstall everything correctly, there are a lot of parts in there. Recheck pop-off, it must be right by this point or you must find the cause. Everything at this point should be clean and debris free, with properly moving needle screw adjusters, idle screw adjusters and chock/throttle plates.

Reassemble the ski. Tell us how it runs.
 
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JetManiac

Stoked
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Location
orlando
So I thought I had the problem solved. The ski ran perfect for about an hour. There was water in the hull I did not have a guard over the coupling and it was shooting water into the intake. Getting everything wet and making it run poorly. So yah come in for a break stuff dried it ran great again. Made sense. So i installed a guard. Rode it for about an hour and it started bogging and dying out. Thought it was out of gas. Which it almost was when I came in and checked. Filled it up went back out and now the ski just completely bogs out and has no power what so ever. It feels like the odd time like it tries to smarten up but nope back to totally bogging down. Checked the plugs they are that perfect tan brown color. So what now????

Updates? Did you figure it out yet?
 
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