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96 XP 787 seems to flood when sitting

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harleytq

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Just bought the ski and put it in water and acted like it had fouled plugs, changed the plugs and it seemed ok, but after shutting it down for a while it did the same thing. So I decided to rebuild carbs, got the kits from OSD, all oem parts it says. Installed everything, going by the carb rebuild thread. The only thing I didn't replace was the springs, because the pop off seemed good to me, at 36-38, would it cause problems being off 2 psi on the pop off?

Put it all back together and it did the same thing, only now even putting in new plugs didn't help, it just seems to be getting too much fuel at idle or just off idle, because it starts and idles good, but as soon as you hit the throttle it just bogs down and runs worse, like on one cylinder.

One question I have on setting the pop off, is when I checked one carb I just slipped the hose on and pumped it up, but on the other carb I had to put hose clamps on the hoses otherwise it would just leak air out of the connections. I couldn't just use my finger to block off the one hose either, it would just leak. Is there something going on here or is that a normal issue?

So I had to get ski over to landing and started on my way just idling, started turning the fuel on off valve, going to off until engine started to kinda smooth out, then I would hit the throttle and turn it just a little to get more gas, and finally it took off and seemed to run good. Then I shut it off and let it sit for a few minutes, started it up and it did the bog thing again like the plugs were fouled, messed with the fuel selector again and she starts running good again.

Should I try new springs, reset pop off, put new needle and seats in?
or is there something else I should look at?
Sorry about the long post, just trying to give a good explanation.
Thanks Tim
 
Any suggestions?
Is it possible it’s loading up while idling?plugs are soaking wet when I pull them. Is it possible that I just need to adjust the Low speed needle, I set it at 1 turn out, would maybe a 1/4 turn in make that much difference?
Is it possible that the previous owner reamed out the low speed jets? What should the size of the hole be in them?
 
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Sounds like the carbs are where they need to be. I'd check compression before moving forward. Then I'd check for leaks in the fuel system. The fuel valve and the water separater are two common places.
 
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Compression is good, I will have to check water separator. Just thinking, if it had leaks or plugged water separator or fuel valve, wouldn’t it be lean?
 
If you have leaks,,air,,,they run lean,,,lean bog,,,even want to runaway,,your needle and seat could be leaking,,2 psi popoff would not cause extra fuel,,,the feeling of running on 1 cylinder can be from poor combustion,,,poor spark,,,even a partially weak battery,,
 
I did put 10 psi in the carbs after assembly, to make sure they didn’t leak. And the needle and seats were new.
I feel pretty confident it is getting too much gas at idle or just above idle.
Maybe I will order a couple new pilot jets, I keep thinking maybe P.O. Screwed them up somehow.
On another note, I noticed a little water under the valve on the water box, I pull the cover off but didn’t notice anything that looked bad. Is there a problem with it?
 
If that water vaLve (Water Control Valve) is leaking you will lose RPM in the higher ranges.
 
Okay,,,take the flame arrestor off,,,have a wide rectangular mirror,,maybe flashlight too,,,start it,,,see if fuel is dripping from the venturi?,,this is called "venturi drip",,,if yes possibles,,,are popoff too low,,,so low that the vibrations of the motor pop the needle,,,another cure besides increasing popoff, is to try 2 anti syphon valves,,,and also,,,happened to me once,,,I was storing machine in the hot sun,,,the vent would not open and the tank pressure poped the needle and gave me tough starts,,,but as i mentioned,,,poor cumbustion can cause wet plugs,,,and weak spark as well...
 
POPPS said:
Okay,,,take the flame arrestor off,,,have a wide rectangular mirror,,maybe flashlight too,,,start it,,,see if fuel is dripping from the venturi?,,this is called "venturi drip",,,if yes possibles,,,are popoff too low,,,so low that the vibrations of the motor pop the needle,,,another cure besides increasing popoff, is to try 2 anti syphon valves,,,and also,,,happened to me once,,,I was storing machine in the hot sun,,,the vent would not open and the tank pressure poped the needle and gave me tough starts,,,but as i mentioned,,,poor cumbustion can cause wet plugs,,,and weak spark as well...
Click to expand...
I read somewhere that someone used 2 different types of lubricant when testing the pop off and they got 2 different readings. Maybe I should use the gas that I am running in it? The previous owner converted to premix, because he thought it was getting too much oil. I thought the issue was fixed but apparently not.
when you say the poor combustion, I keep thinking maybe bad gas, but the thing started with a touch of the button. Then I added about 5 gallons of fresh gas. What’s your thoughts?
 
Ok I checked water separator, and vent for tank. Tank vent was plugged, but removing it has no effect on running problem.

I don’t see any fuel dripping from Venturi.

Running it yesterday, it starts right up, sounds like it’s running good for maybe 1 minute, then it starts this really bad miss on the mag cylinder. And this seems to happen every time you start it.
 
Could be a bad wire from the coil in the Ebox,,,switch the plug wires,,,see if the issue follows the wire?,,,if yes,,,pull the coil,,and pull the wires out,,sometimes water gets trapped in the coil cavity and rust builds up on the wire,,,could even be a bad coil,,,it warms up and like many electrical failures,,,fails after it gets hot.
 
To the comment on tank venting. My unit had a tank pressure issue, I almost lost the tank cap while fueling at a marina. the chain was off and it blew off as I removed it in the hot sun. The vents were 25 yr old. They were the original so I replaced the lines and sprayed air intake cleaner in the intake and exhaust vents. Solved the pressure and solved the hard starts which I believe were a flooding issue from excessive fuel leakage into the cylinders. Mine did not foul while running. On the flip side. I had a real fit trying to set the pop offs when I used a china kit and SBT china needle and seat. Ended up using the old ones and ordered oem parts for later. But I think it sure wont hurt to redo the carbs. I also pressure tested the fuel pump and flat sanded the pump base as the previous mechanic over torqued the assembly and tweaked the bodies causing leakage
 
I switched spark plug wires, no luck, the front cylinder still missing. Rear seems to run good.
I’m still thinking pull carbs again, not sure what to do?
 
Could it be something with the timing of the rotary valve? Not sure why that would be off, but who knows with that previous owner. He said he just did the wear ring, so I looked at the carbon ring, it is totally shot, can’t believe it wasn’t leaking. Or I guess it didn’t run long enough to see it. I was getting really bad cavitation though, so at least I know why that is. Lol
 
The rotary valve timing being off wouldn't be good then bad, just would run bad all the time.
Sure sounds like electrical.
 
Something I just found today, the plug on the front of engine, guess it for the stator, looked kinda corroded, the rubber seal is missing on the plug.
Do you think that would be my problem?
On another note,
I pulled the carbs again, to replace the springs on the needles, and pretty much got the same pop off as the old springs. But anyway I wanted to ask you if the OSD back to OEM kit has the right springs with it? Or should I ask them, to make sure? They do look black so I'm thinking they are right.
 
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