New 440 with Running Issues

[brapperdoodle]

Ive been doing some work to a 1990 Kawasaki JS440 and I’ve been running into some trouble and wanted to reach out for some suggestions. I’m really excited about this ski and even more excited to share it with the kids and ladies. So I’ve done a bit of research and some diagnosing, but it seems like the engine is flooding out. I originally did a compression test coming up with 110psi on each cylinder, also did a pressure test and discovered a leak on the lower intake carb gasket. I replaced the gasket and rebuilt the carb a couple days ago and was very thorough and clean, not my first rebuild though I’ve been wrenching seriously for over 10 years but I’m new to PWC carbs. I replaced the stock 1.5 needle and seat with a 2.0 and that put my pop off pressure at about 8-10psi. High and low screws were set to stock settings. The ski fired right up and idled excellent. Revved cleanly and I was ready for a lake test. Started up the next morning no problem but When I got to the lake later that day, the ski didn’t even try to start. I noticed pooling of fuel in the intake manifold, I flipped the ski and turned the engine and of course fuel was dripping from the carb. I did get the ski to start and put it in the water. It ran great and I didn’t shut it down for 30 minutes, we took turns riding it to try and “clear it out” and it ran well the entire time. But after letting the ski take a rest, no start. Ran the battery dead trying. Then hours later the ski fired up instantly when touching the start button but then spuddered out. The plugs look great, nice mocha color and not wet. So does anyone have any suggestions on things to check for? Any help is greatly appreciated!

 

[wmazz]

I originally did a compression test coming up with 110psi on each cylinder,

Your compression gauge reads low.

also did a pressure test and discovered a leak on the lower intake carb gasket.

Did you remove the inspection plug of the front cover? The most
common problem is the front main seal leaking vacuum. That is why a
pressure/vacuum test is necessary. Or test the front main seal with
the engine running (ask).

How did you apply the pressure? through the pulse line.

I replaced the stock 1.5 needle and seat with a 2.0 and that put my pop off pressure at about 8-10psi.

Pop-off is to low. It should be at least 12 psi. Max fuel pressure is
7.5 psi. Your pop-off is too close to the fuel pump pressure.


Bill M.

 

[brapperdoodle]

Your compression gauge reads low.



Did you remove the inspection plug of the front cover? The most
common problem is the front main seal leaking vacuum. That is why a
pressure/vacuum test is necessary. Or test the front main seal with
the engine running (ask).

How did you apply the pressure? through the pulse line.



Pop-off is to low. It should be at least 12 psi. Max fuel pressure is
7.5 psi. Your pop-off is too close to the fuel pump pressure.


Bill M.

Hey Thanks Bill! My compression gauge reads low? I assume you mean that the reading is low, I thought that was a bit low myself but from what I was reading it was an acceptable number. Do you have a spec for proper compression on a healthy 440?

I did remove the inspection plug on the front cover, I suspected a leak there because before the carb rebuild the ski didn't hardly run and was gooping out of the exhaust. yuck. I thought it may have a crank seal leak but I didn't hear any air coming from that hole. I will pressure test this ski again in the next few days to re-confirm leakage. I am using the Group-K Pressure Test Kit. Its a nice low pressure liquid gauge with a fitting for a pulse line and a bicycle pump. So yes I am testing pressure by pumping air into the crankcase through the pulse line. Harry sent me some information on pressure testing also, its pretty clear instructions.

I was not sure about the pop-off, I read on the Group-K website that pop-off pressure should be between 8-12psi. I will order I new 1.5 needle and sea though as I also think that the 2.0 needle is probably a bit much. Do you know where to source these? OEM?

Also I want to note that I could see spurts of oil mixture creeping up the pulse line when I did get it running. Im wondering if this has been filled with gas/oil since before the carb rebuild and I still haven't properly "drained" the engine. I was under the impression that it would just clear out if it were running. Is flipping the ski over the easier method for clearing the crankcase and cylinders?