do you need to open the carbs up all the way to do a compression check?

[cocacola]

I just acquired 2 Kawasaki's to go with my Seadoo.

In the past, I have always done a compression check on a cold engine, but until today....did not know I was supposed to open carbs all the way.

Is that true?
Is there a different procedure?

• Seadoo 720 (new rings) I am getting 150-153
• Kawasaki ZXI 1100 with big bore kit 118-120-118
• Kawasaki STX 900 105-105-105

should I take new readings with carbs wide open?

It surprises me that the Seadoo has much more compression.
Maybe I need to re-ring the 900

 

[mikidymac]

Yes, always full battery and throttle wide open.
Do not use the Harbor Freight compression gauges.

The triple cylinders are a little lower compression. You should be seeing 120 psi so the ZXI is good to go. The STX is a little low at 105 but seeing as they ae dead even I would run it and see how it does before messing with the engine.

As always with any used ski tis' a god idea to rebuild the carbs with Genuine parts and check the fuel system so you don't seize an engine.

 

[cocacola]

Yes, always full battery and throttle wide open.
Do not use the Harbor Freight compression gauges.

The triple cylinders are a little lower compression. You should be seeing 120 psi so the ZXI is good to go. The STX is a little low at 105 but seeing as they ae dead even I would run it and see how it does before messing with the engine.

As always with any used ski tis' a god idea to rebuild the carbs with Genuine parts and check the fuel system so you don't seize an engine.

Perfect! thank you

 

[robin savell lloyd]

I would say 105 very well maybe normal especially their all even mine was reading about 105 and it has only 70 hours on it

 

[robin savell lloyd]

I wonder if Kawasaki may have tuned it down so it would last longer