Super Jet Rookie carb tuner, need help tuning sbn 44

codyadams209

codyadams209

Location
Lodi
Hey so I picked up a superjet the other day with a 61x 701 for super cheap and the guy told it had carb trouble and it was acting up on him, well we took it to the water and it would idle but soon as you go past quarter throttle it would fall flat and die, I didn't really care about the carb because of how cheap it was, so then the next day I went to a buddy and bought a low hours sbn 44 that he took off a waveblaster, I opened both the carbs up and used the best parts from inside each of them to build the cleanest carb possible, I cleaned out the tiny filter inside the carb and used clean carb gaskets, o rings, and a clean diaphram, I put it back together and I got the low speed set and like 2 1/2 turns out but no matter where I put the high speed it still will fall flat in the water unless you really slowly ease onto the gas then you can get up to like 70% of full speed, the 2 things I am concerned about is the jet size in the carbs, idk who has gone through this carb, and the diaphrams, in the middle of one diaphram it has a red metal dot to push the needle and the other one its silver but the silver one is not quite as tall as the red one but the red diaphram is dried up and no good so I'm stuck with the silver one, oh and i also am using new fuel lines with a new filter and the tank vent is good and the reserve line is plugged off because I am not using the controls on the dash just straight to the carb from the tank, thanks
 
Vumad

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
codyadams209 said:
Hey so I picked up a superjet the other day with a 61x 701 for super cheap and the guy told it had carb trouble and it was acting up on him, well we took it to the water and it would idle but soon as you go past quarter throttle it would fall flat and die, I didn't really care about the carb because of how cheap it was, so then the next day I went to a buddy and bought a low hours sbn 44 that he took off a waveblaster, I opened both the carbs up and used the best parts from inside each of them to build the cleanest carb possible, I cleaned out the tiny filter inside the carb and used clean carb gaskets, o rings, and a clean diaphram, I put it back together and I got the low speed set and like 2 1/2 turns out but no matter where I put the high speed it still will fall flat in the water unless you really slowly ease onto the gas then you can get up to like 70% of full speed, the 2 things I am concerned about is the jet size in the carbs, idk who has gone through this carb, and the diaphrams, in the middle of one diaphram it has a red metal dot to push the needle and the other one its silver but the silver one is not quite as tall as the red one but the red diaphram is dried up and no good so I'm stuck with the silver one, oh and i also am using new fuel lines with a new filter and the tank vent is good and the reserve line is plugged off because I am not using the controls on the dash just straight to the carb from the tank, thanks
Click to expand...

Just because a carb is clean does not mean it is working right. When you put a carb together, you need to pressure test it. One test is to ensure there are not leaks where it holds 10 psi for 10 minutes. The second is that it has a crisp popoff at the correct pressure.

Next the jetting situation. You need to have at least a baseline jetting spec to start with. I don't think any of the skis came stock with a single 44 SBN, so you need to get specs for your setup from someone else. There is a carb tuning database thread you can check or hopefully someone can tell you something close. I do not have the specs for a single 44.

Next you need to read the mikuni tuning manual. Then read it again. Then start tuning the carb. Then alternate between the two until you understand it.

Last you need to buy a tach. I use Hardline but there are other models. You dial in the top end with a tach.
 
codyadams209

codyadams209

Location
Lodi
Vumad said:
Just because a carb is clean does not mean it is working right. When you put a carb together, you need to pressure test it. One test is to ensure there are not leaks where it holds 10 psi for 10 minutes. The second is that it has a crisp popoff at the correct pressure.

Next the jetting situation. You need to have at least a baseline jetting spec to start with. I don't think any of the skis came stock with a single 44 SBN, so you need to get specs for your setup from someone else. There is a carb tuning database thread you can check or hopefully someone can tell you something close. I do not have the specs for a single 44.

Next you need to read the mikuni tuning manual. Then read it again. Then start tuning the carb. Then alternate between the two until you understand it.

Last you need to buy a tach. I use Hardline but there are other models. You dial in the top end with a tach.
Click to expand...
It's got a 135 high idk how to tell what the low is, I got it tuned decent but if I punch it from a idle it cuts out, if I ease into it then I can pin it
 
mike b

mike b

Michael "Mayhem" Bevacqua aka MikeyChan
Location
California
codyadams209 said:
It's got a 135 high idk how to tell what the low is, I got it tuned decent but if I punch it from a idle it cuts out, if I ease into it then I can pin it
Click to expand...

To check the low jet you have to remove it and look at the side of the jet, it will be printed on the side like how the high jet is printed on the top of the jet
 
eastcoastjumper

eastcoastjumper

James
Site Supporter
Location
Long Island
codyadams209 said:
It's got a 135 high idk how to tell what the low is, I got it tuned decent but if I punch it from a idle it cuts out, if I ease into it then I can pin it
Click to expand...

What's the setup on the motor? You need 147.5 main and 120 low for b pipe, head, msd, etc. Use a 2.0 needle and seat and get the pop off to 20 psi. It will guarantee run and rev out with that setup at sea level.

@Vumad, every single 61x motor couch came with an Sbn 44 stock.


Sent from my iPhone using Tapatalk
 
eastcoastjumper

eastcoastjumper

James
Site Supporter
Location
Long Island
mike b said:
When taking the jets off, obviously you need a small enough screw driver. But also I was told to tighten a bit, then loosen to remove the jet.
Click to expand...

Use a fresh screwdriver of the appropriate size for the pilot jet. I use this..

f0fbbaa488a11ca3b78baf3c0eefc4eb.jpg



Sent from my iPhone using Tapatalk
 
You must log in or register to reply here.
Top Bottom