Popoff on a '94 XP

[ShawnXB]

Well, parts came today (Thx Bill). So I'm in the process of breaking down the carbs. Decided to look at the popoff pressure on the carbs before I took them down. Both were right about 40 psi. If I recall, you're supposed to be around 19-25 aren't you? What happens when your popoff is too high? Low end bog? I hope.

[1fastski.com]

Re: Popoff on a '94 XP

most of time you see harder starting with high popoffs .. 15 to 25 is a good setting

[Technical Support]

Re: Popoff on a '94 XP

If you're stock 40 is just about right, 28-38 or so is stock.

[Bill O'Neal2]

Re: Popoff on a '94 XP

39 psi is perfect. But, make sure it holds at least 20 psi for 3 minutes.

[ShawnXB]

Re: Popoff on a '94 XP

I'm starting to get a tad bummed out. I was thinking that the bogging was due to bad popoff, i.e., leaky needles and seats. But if my popoff is good, then it's not the needles and seats. Any further suggestions?

[Bill O'Neal2]

Re: Popoff on a '94 XP

Do they hold the pressure, or do they leak when the engine is viberating ?

What is the compression of the two clyinders?

Are the throttle shafts in the carbs worn to the point they move up and down when in an on throttle position ( not fully closed). You can check them with your hands while they are on the ski.

[ShawnXB]

Re: Popoff on a '94 XP

Do they hold the pressure, or do they leak when the engine is viberating ?

Don't know. They're broken down right now, so I'll have to wait until the new needles and seats to go in to say for sure.

What is the compression of the two clyinders?

150 psi in both.

Are the throttle shafts in the carbs worn to the point they move up and down when in an on throttle position ( not fully closed). You can check them with your hands while they are on the ski.

No they seem to be in very good condition.

[Bill O'Neal1]

Re: Popoff on a '94 XP

Good to read you are replacing the needles and seats. They cause alot of carb problems when they are wornout. Go ahead and re-install the carbs and see if you still have the problems.

[ShawnXB]

Re: Popoff on a '94 XP

You do remember you sold them to me, don't you? LOL. Ok, another question. Below you guys mention that 39psi is perfect, but my service manual says 16-21 for XP carbs in terms of popoff. So which one is correct?

Finally got the second seat out. Holy Sh(t. I'll have to take a picture of it. Finally had to ram it through from behind to get it out...

[ShawnXB]

Ok, more questions. I'm working on the mag pto side carb and noticing that in the manual it doesn't show a diaphragm on the filter side of the carb.

If you look at the microfiche <here> of the pto carb, you will notice that it does not have a number 52 diaphragm on there. But when I took the carb apart, it had that diaphragm in place. Did some one screw up? Is the diaphragm *suppose* to be in there? It's not in the microfiche, but it's in the carb.

[ShawnXB]

Re: Popoff on a '94 XP

I have the carbs reassembled (still need confirmations for questions below), and using the new silver springs and the new fulcrums, the popoff pressure is about 42psi for both carbs. Is that high, or will it be ok? That's using a mikuni popoff gauge btw.

[Bill O'Neal1]

Re: Popoff on a '94 XP

That diaphram is not necessary if you have the oring in there, but I usually put it in anyway. It is more of a gasket than a diaphram, as it doesnt move and pump anything.

No, I didn't remember selling you the needles and seats. You might find this strange, but I'm old and can't remember s***, especially when I deal with so many different people on a daily basis.

I do not have my manual here, but 16-21 psi sounds way too low to me for a 94XP. Are you sure about that?

[ShawnXB]

Re: Popoff on a '94 XP

Do you think the manual was written to assume 16-21 psi over atmospheric? That seems to be the consensus from other sites as well. They mention the leak down test should be done at 10 psi which is below atmospheric...

[Bill O'Neal1]

Re: Popoff on a '94 XP

No way. And the leak down is 10 psi on a pressure guage, not atmospheric pressure.

The consensus ?.......... Interesting.

[ShawnXB]

Re: Popoff on a '94 XP

No, what I'm saying is that my gauge is reading in atmospheric. It reads 15 psi right now. So by saying leak down is 10 psi means my gauge needs to read 25 to actually attain *their* version of 10 psi. Does that make sense? I just need someone to confirm this for me so I can put the things back together.