Pop off question

[Hunterb]

Hi all,
So I built a tester to see at what pressure my needle valves were 'popping' at and, if I did the test right they both pop right around 20psi. This seems quite low from what I have read. To do the test I just assembled a line with a T for a gauge and attached one end to the inlet of the carb and the other to my compressor and then increased pressure till the popped. I had them filled with wd40. They seem to pop reliably right at 20psi.
From what I've read that is lower than it should be so I have a couple questions.
1) Is that a problem?
2) what is the best solution if it is a problem.
3) when I was doing the test I could hear air escaping from somewhere as pressure built up. Is that normal? I did not plug the return lines.
Thanks in advance if you have any suggestions.
Bruce

 

[JeremyD615]

What year and model ski is it? The popoff specs are different for the different setups, so we will need to know that to give you any useful information. On some of the skis/boats, 20 is within spec, and on most of them it’s not...

 

[Hunterb]

Yes, thanks for that. More info in my original post would have been useful. It is a 1997 GTX with the 787 motor. I also need to fix my tester because it was really difficult to control the air flow with my compressor. I think a tire valve and hand/bike pump would be better.

 

[JeremyD615]

Well you’re not too far off then. The spec for your ski is from 23-43psi. I would pick up a bike pump and use that to retest your popoff. I know a lot of people will recommend that you try to get in the middle of that range, but I generally don’t mess with them if they are anywhere in the range unless you have running issues.

 

[Hunterb]

Thanks!! I rejigged my tester and redid the test and I got better results. They both pop at 28 psi so I think that's fine and I won't mess with them. I'm cleaning and checking the carbs while I wait for the machine shop to fit a new set of pistons because something fairly traumatic happened to this motor before I bought it. Definitely had parts come off and go through the top end. Both HS screws were turned way out as well so I'm not sure what was going on. I'm hoping with a fresh top end and everything set right in the carbs that it will run. Time will tell.

 

[Hunterb]

Thanks!! I rejigged my tester and redid the test and I got better results. They both pop at 28 psi so I think that's fine and I won't mess with them. I'm cleaning and checking the carbs while I wait for the machine shop to fit a new set of pistons because something fairly traumatic happened to this motor before I bought it. Definitely had parts come off and go through the top end. Both HS screws were turned way out as well so I'm not sure what was going on. I'm hoping with a fresh top end and everything set right in the carbs that it will run. Time will tell.

 

[JeremyD615]

Just make sure you get the transition ports cleaned out well on the carbs. I like to take one of the old check valve grommets and push the straw from a can of carb cleaner through it. It helps seal the nozzle up and get a little more pressure behind the cleaner when it goes through. Follow Miki’s carb rebuild sticky and you can’t go wrong.