Pop off pressure drops at pop off threshold, but does not actually pop.

[SW MO Guy]

Hi:
New member here. I have a 2001 GTS and have rebuilt the carburetor. It is a BN40 with the accelerator pump. All the basic tests pass with the OEM Mikuni kit installed except for the pop off. I can pump it up to about 35 lbs. with the SBT pump and then it drops about 5 lbs. on the gauge. So, not an immediate and full pop off. Is it supposed to “pop” and drop immediately to zero? Original spring used and seat and needle appear perfect. Thanks for reading and providing any ideas. I’ve read many posts, but not quite like my issue?

 

[KyleW2]

Are you wetting it with WD-40 before testing?
I've had that happen when the needle/seat isn't wet enough.

And no, it should not drop to zero. It will pop and then it should reset itself and hold at a lower PSI level. I'm not sure if there's a specific number it should hold at though, haven't seen one in the manual.

 

[etemplet]

Should hold around 15 pounds for so many minutes I don't watch them long. It's easy to see of they are leaking and you'll see bubbles coming from the needle area through the WD-40. I use a lot of new needles and seats. The hold tight at damn near pop off pressure. I have GTXs hold at 30psi with a pop off of 38.

Pressure the carb up to 15Psi and check the joints with soap bubbles. Good Luck!

 

[SW MO Guy]

Thanks Kyle and etemplet:
I appreciate the help. I tested the pop off again by soaking it with more WD-40 and it popped off nicely at about 36 lbs. After popping, it dropped and held at about 30 lbs. Also, it will hold almost indefinitely at 15 lbs. Specs call for 38-40 lbs. for pop off, but hopefully 36 is close enough? Thanks again for both of your responses.
Randy.

 

[etemplet]

That's pretty tight specs for Pop-off so I checked. This isn't the offical Seadoo Manual but I use this site often. Pop-Off is listed at 36-40PSI here. Pop-Off and carb info I think you are Okie Dokie at 36psi. For general information the lower the Pop-Off the Richer the carb so highter is leaner. Good Luck !!

 

[SW MO Guy]

Thanks etemplet for that additional info. I’m going to try it out later this week after getting rid of those grey fuel lines.

 

[POPPS]

When I check pop/offs,,,I use a bottle of gas ,to closely replicate the fuel entering the sest.,,WD is so slippery.

 

[SW MO Guy]

Thanks Popps. That makes a lot of sense. Randy.