1996 xp won't start in the water but fires up out of the water

[Bandit-911]

I have a I have a 1996 xp that won't start in the water but fires up out of the water. I pick the machine up out of the water and put it in the water running it runs. I turn it off in the water it won't start.

The compression is 160 on both cylinders. I did a rebuild on the carbs and had a problem with the ski flooding after it was shut off for a while because the needle valve was being held a little open by the aftermarket Diaphragm gasket. To fix that problem I bought the Mikuni rebuilt kits and fixed that problem. When I tested the pop off it was at 36 to 39 on both carbs which is at the high end of the range. (range is 27 to 39). Battery is good new plugs I just can't figure this one out.

Also when I had the flooding issue the ski did backfire a couple of times when I was trying to figure out what was wrong.

Any help would be appreciated.
C. I pick the machine up out of the water and put it in the water running it runs. I turn it off in the water it won't start.

The compression is 160 on both cylinders. I did a rebuild on the carbs and had a problem with the ski flooding after it was shut off for a while because the needle valve was being held a little open by the aftermarket Diaphragm gasket. To fix that problem I bought the Mikuni rebuilt kits and fixed that problem. When I tested the pop off it was at 36 to 39 on both carbs which is at the high end of the range. (range is 27 to 39). Battery is good new plugs I just can't figure this one out.

Also when I had the flooding issue the ski did backfire a couple of times when I was trying to figure out what was wrong.

Any help would be appreciated.

 

[timmyboy76]

have battery load test at auto store. Its free, and give you piece of mind, its something else. A battery will show 12.whatever volts, then hit start/stop button, it'll drop to 11/10 ish volts.

 

[Bandit-911]

battery is good. I think it has more to do with the carbs and the pop off. I wish i saved my old diaphragms.

Thanks for the repy

 

[nester]

Im having the same issue with mine. It will start great cold, but I think the new diaphragms in the carbs might be holding the needle vavle open and flooding her like you said. is there any way of fixing this without ordering a new carb rebuild kit? Would like to be out on the water this weekend.

 

[timmyboy76]

Im having the same issue with mine. It will start great cold, but I think the new diaphragms in the carbs might be holding the needle vavle open and flooding her like you said. is there any way of fixing this without ordering a new carb rebuild kit? Would like to be out on the water this weekend.

bend the "tang" down, that hits the red button of the diaphram..

 

[nester]

Bent them down a little today. Putting her back together tommrow then off to the test course at the lake sat. Thanks for the help:hurray:

 

[seadoobutch787]

Always use genuine Mikuni rebuild kits! When you rebuilt your carbs did you put the spring that came out of the carb back in or did you put one of the springs in the carb from your aftermarket kit?

If so you might have changed the pop off and that will make the ski run like you stated. It will fire up with new plugs and run but if you shut it off it will be a bitch to start. You will have to take the load off the engine and it will fire up. The plugs will usually be fouled from the extra fuel.

 

[Bandit-911]

Always use genuine Mikuni rebuild kits! When you rebuilt your carbs did you put the spring that came out of the carb back in or did you put one of the springs in the carb from your aftermarket kit?

If so you might have changed the pop off and that will make the ski run like you stated. It will fire up with new plugs and run but if you shut it off it will be a bitch to start. You will have to take the load off the engine and it will fire up. The plugs will usually be fouled from the extra fuel.

Yeah I got a the genuine Mikuni rebuild kits. I did use my original springs and fixed the flooding problem but now the ski won't start when the muffler or back of the ski is under water. If it is up just a llittle it will start.

 

[seadoobutch787]

If you have a stock 96xp waterbox the baffles are known to break off inside the waterbox. It might restrict the exhaust flow when it's in the water. It's worth a look.

 

[Bandit-911]

you might be on to something seeing I have tried every combination in the world with the carb set up. The ski did back fire hard a couple of times when i had the aftermarket diaphragm in it.

 

[seadoosnipe]

Pop off....

Saying you fixed the flooding problem leads me to believe you had a low gram spring installed. So, it seems you changed it. If you have a problem getting it to start now, then you might have put a spring in that is to heavy.

What is your pop-off? Put the ski in the water without the airbox on but have the flame arrestor on. Carry a grocery store plastic bag with you.

With the seat off, tied to the dock, cover your flame arrestor with that plastic bag. Now, try to start the ski. As soon as it starts, remove the bag as quickly as possible. Now it's running: if it dies out on you, the pop-off is to high. Cut a ring from your spring or change it to a lower gram size spring.

You already experienced what caused the flooding, you had less than 20 psi on your pop off. Now, increase that by about 5 psi and you might get better results. Don't change the spring and have a pop off at 30. That's a heavy jump.

The exhaust in the water has nothing to do with it. In a way anyway. What your doing on land is building manifold pressure (vacuum) easier because the engine is not torqued up from the impeller. When you put it in the water, your not building as much vacuum because the moment you hit the start button, the impeller begins to torque up the motor..........:cheers: