PSA: Setting Mikuni carb pop-off on your PWC carb is essential to proper performance!!

I've had a pile of PWCs recently come in that have run poorly, hesitated, bogged, even surged and stalled.
All of it due to the pop-off pressure being set incorrectly.

Some of the most clear information I've seen anywhere on setting up carbs on carbureted skis at Seadoosource:

Key things in video:
0:00 Introduction
0:42 Why setting the popoff is vital to proper performance
1:40 How the needle/seat and diaphragm functions together
2:10 Pump and how hoses need to connected be to test
3:12 Testing popoff
3:48 50psi popoff
4:23 Installed correct spring, ready for re-test
5:00 32psi with correct spring, dead on in the middle of the spec
5:20 Don't be a fool, test your popoff with the tool

Links to products could be affiliate links, which earn me a small commission on your purchase for referring you, and best of all, it doesn't cost you a penny more!

[trythistv]

Links to products could be affiliate links, which earn me a small commission on your purchase for referring you, and best of all, it doesn't cost you a penny more!

[mitchellbolton]

LOL love your tongue-in-cheek approach to "PSA". No need to "apologize" when rendering such an invaluable FREE service-if anything more gratitude should be rendered to yourself and other Youtubers for such info.!! In other words, thanks, ha ha ha no need to apologize there, buddy!

[gto]

Wow, wish I had this knowledge in 2005, xl800 has always ran rough until 1/2t. After I rebuilt the carbs in 2005. Ffwd 16 years, and I rebuild them again - yet right this time! Thanks a

[frodiesel]

Brap! It’s summertime where’s your pop off at! Great video

[richardanderson]

I appreciate this video my pop off was definitely an issue. neither carb was accurate. Where I ran into most issues is with accelerator pump"tiny little parts" and adjusting the arm and understanding how it works, i could not bench test the item. Good news is we are going out Jet skiing this week!

[RobausYTTV]

I ordered that pressure tester, should be here Friday. I rebuilt my carb today and then took the ski to the lake and no matter what I did with the high and low speed adjustment, wouldn’t work properly and by what you said, sounds exactly the issue. I’ll let ya know how it works out. But regardless thank you so much for the information man!!!

[AwesomeOakTree]

That is the exact issue i am having with a ski! I will have to take a look at this and see if it fixes the low end bog!

[ace]

I have a Yamaha Waveraider 760. Have several newer Seadoos 4 strokes with zero issues. However wanted to try an older smaller two stroke out. Just did a top end rebuild/bore on it and it sounds and runs great. Is converted to premix. Used premium fuel with a 40:1 mixture. It starts first try everytime and idles great. It also runs great up to about half throttle anymore past that and it bogs down. I’ve no idea why was thinking maybe could be the carbs but wasn’t sure? Sound like a carb issue if it starts good, idles good, runs good to half or even 75% throttle but soon as hold it wide open it bogs way down. Any ideas?

[phildawe]

thank you!! this video just solved an enigma of how to test pop off.
it may also be the reason why my 3rd piston melted into a globule of aluminium and siezed the engine from a too-lean situation in only one cylinder of a gp1200r the other day.

[rickl]

Mine are popping off at 24psi (both carbs) but after they pop off one of the carbs leaks down to 0. Another YouTuber said you should go down 10 to 15 psi and hold after the carb pops off. One of my carbs isn’t holding. Any recommendations?

[jackhanneken]

Awesome video! I have a 2003 xlt 800. I have been through 1 engine and 2 top ends, I just replaced it with another engine, it keeps seizing pistons and I can't figure out why. I have done multiple carb rebuilds and have tested pop off. It ran real good last year with a black spring and 1, 2 seat. It popped off around 60. However it seized a piston when going full speed for a longer period of time which leads me to believe it may have been running lean. I did not do a plug chop test on that setup to check my high speed and that may have been my problem. I currently have a 1.8 seat in there and 115 g spring as I am on vacation and only have 115 g springs and 80g springs to test with. I am going to try to put the 80g and 1.2 seat back in to solve the problem. The ski also ran away on me on the trailer with this setup so I am scared to go back to it. Any ideas on what could be causing my issue? Cooling system seems to be working and I changed fuel filter as well.

[johnarakawa]

My mikuni pop off tester not holding pressure, needle goes to 10psi then needle drops rapidly, checked all connections and off carb pumps up and holds pressure....ideas, is it the needle or seat?

[gabrielebrombin]

You are a life saver. Thanks, Very informative.

[danbergeron]

I tried to test the pop up but I’m not able to hold any pressure? Is that an indication that the fuel pump gaskets aren’t sealing?

[MrScottgp]

Great video, my question is I have this same carb and when I test the pop off the seat starts to come out too. What holds it in? I know there is a screw next to it but it doesn't look like it holds anything?

[leoolv]

Very nice video! Is there any chance, that because of this, PWC would run on ground while dry but not when in the water? All of the other sympthoms are the same

[hankhamadi]

How do I order a Guage like this?and whats is it called?

[СергейКузьмин-пя]

Здравствуйте, подскажите какой пиапсай должен быть на гидроцикле 760 RA 96г.Второй сезон чиню карбы толку нет, запускается отлично газуется на холостых, как только спускаю на воду даю газу глохнет, менял ремкомплект не помогает увидел это видео может дело в пиапсае, как все это настроить?

[lionsdejudah]

I have a 1998 Seadoo Speedster 1800 with 2 Rotax 717 engines, I want to remove the stock fuel pumps and replace both of them with 1 electric fuel pump, my question is would the fuel pump need to put out 21-37 PSI? For the carbs to pop?

[MarshallSmith]

my 1989 waverunner 500 has a hesitation off idle. if I remember right it was 12 psi when I rebuilt the carb last month? do I need more pressure than 12 psi?