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97 xp 787 runs fine then just dies.

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wholf09

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I have a 97 seadoo xp it idles great and has great throttle response, perfect compression (150psi both cyl.) the rave valves are clean and it will turn over freely by hand with the spark plugs out. but when out on the river it will run great for about 5 min then just die like a kill switch kicked in . Then it will start back up after about 3 min and run fine for 5 min and then it does it again.The motor is not hot i can touch it and it is just warm.I replaced the coil and it still does it.

I just had it rebuilt,so i assumed that it was something electric seeing how it cuts out so quick and starts back up fine, if yo know what could be wrong please help.thanks
 
It sounds like it might be the DESS lanyard is dirty or has a loose wire connection. If the DESS loses communication with the MPEM it will do this too. Clean the lanyard and post with soap and water. Don't use anything on the cap or lanyard. The ROM (read only memory) chip in the lanyard cap could be damaged if you put grease or anything on it. Be sure you get 2 beeps when you connect the DESS. If the cleaning doesn't help check the wires for a bad or dirty connection. If it is still not working it might need a post replacement.

Karl
 
Could that be it.

Could that be it ? The ski runs great for 9 min (I used a stop watch.) then dies ,then i wait for 3 to 5 min ,then i start it up it runes for 9min then does it again, i could do this all day. could the lanyard do that ?Thanks
 
Yes. When it dies, wiggle the DESS lanyard on and off and see if it starts right up. If it does, it must be in the DESS connection. If it's the DESS connection time doesn't matter really. It could be something else, but it sounds like that could be your problem.

Karl
 
Could also be a bad ground...

Try running it, but NOT at full speed. See if it does not cut off, and as soon as you go full speed for a few minutes it will cut off = bad ground.
 
sounds like rectifier, they can do weird things when they go out. easy test to disconnect the red wire and run on the battery.
 
Update

I preformed the DESS self diagnostic and at first when I pushed the start button 5 times and got a beep then put the key on I got two short beeps. I next proceeded to clean all electrical connections and preformed the test again.This time it started, and instead of quite beeps I got very loud ones.

This however did not fix the problem, It will still die after running It for a number of min,It will however run all day at an idle.

I did notice a stream of air bubbles moving in the carburetors flue lines (My lines are clear).Could the air in the lines cause the engine to cut out, or is that normal?

Also when it does die i can wiggle the key and unplug and plug it back in all day long ,this does not help.If i unscrew the spark pluges and turn the engine over ,then put the pluges back in it will start right up.
thanks:
caleb
 
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Tried new ground,no luck

I tried a new groung and the ski still does the same thing. I checked the voltage from the + post on the batery to the block and i got 12.5 volts.

Any more ideas guys?


Also how many grounds are there? and where are they?
 
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wholf09 said:
I preformed the DESS self diagnostic and at first when I pushed the start button 5 times and got a beep then put the key on I got two short beeps. I next proceeded to clean all electrical connections and preformed the test again.This time it started, and instead of quite beeps I got very loud ones.

This however did not fix the problem, It will still die after running It for a number of min,It will however run all day at an idle.

I did notice a stream of air bubbles moving in the carburetors flue lines (My lines are clear).Could the air in the lines cause the engine to cut out, or is that normal?

Also when it does die i can wiggle the key and unplug and plug it back in all day long ,this does not help.If i unscrew the spark pluges and turn the engine over ,then put the pluges back in it will start right up.
thanks:
caleb
Click to expand...

One thing that needs to be addressed is the air getting into your fuel system. Check the fuel filter O ring and make sure it is not damaged or leakng. This simple item will can cause big headaches. Best thing is to replace it with an inline filter from your local lawn mower shop. :cheers
 
Oring

I will check the o-ring. I just can't see the ring causing the ski to shut off suddenly then act like the battery is low causing the engine to not turn over until i pull the plugs and turn the engine over, or wait for a few minutes until it will turn over. Thanks as for the plugs being right or not, I have been using the same type of plugs in it for years so I do not believe that is it, but what type do you recommend?
 
I hate to make one more suggestion...

but mine did this as well. I swapped out all kinds of stuff, and what fixed it was replacing (not cleaning, but actually replacing) the fuel selector switch.

Might explain the air in the fuel lines, too.

I agree with above. Just bypass the crappy fuel filter with the o-ring replacing with one from the auto parts store.

Is that Beaumont TEXAS?
 
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You will also find that if you have a primer installed, you can keep it running by priming it when it starts to die.

You are losing the pressure in the fuel system, and it is sporadic. I never figured out why it would run fine for 5, 10, 30 minutes, then all of a sudden die on me.

I ended up swapping out the entire fuel system, all the lines, filters, etc. The last thing in the mail to me (split order) was the fuel selector switch, and when I swapped that out, it hasn't died once since.

So I had the entire system swapped, and it was still dying on me for another week. Then the switch came in and I put it in the following weekend, and problem was solved.

I am still stumped as to why it would run for a while then all of a sudden just die...:confused:
 
Charging circuit....

At first, you were describing the exact situation if you had a bad DESS post, which you still may have. But, in reading on through, you mention that it appears the battery is weakened by this.

No where did I read you checked the charging system with a volt meter. Start the motor on the hose. Check the battery to see the charging circuit works. If your not familar with a volt meter, buy a cheap one from Walmart and set it to 20 VDC. Then, with the engine running, touch the red to the positive and black to negative. You should see anywhere from 13.5 to 14 vdc. If you only see voltage in the 12's, then you likely have a problem with the charging circuit or like mentioned above, the rectifier.

But, from what I'm reading, I put money on the DESS post, if the charging circuit tests good..........

I had this happen to my boat. Running along, having a good time, then shut down like someone snatched the lanyard off the post. I can take the lanyard off and put it back on and it might run good for an hour, or 5 minutes. This happened for about a month and only got worse. I replaced the post and have not had the problem since.......If it's something like the fuel system, you should get something like a sputtering or the sound of going down on one cylinder before dying. Nothing on the engine will cause it to sound like someone is pushing a button, killing electrical power but the post.:cheers:
 
Thanks

Thanks for all the help guys, I am just confused, could DESS cause the motor to not be able to turn over, or act like the battery is low? I mean when it does die it does it so suddenly that it makes me believe that it is an electrical problem, however I am at a loss as to how the system losing the signal from the DESS could cause the electrical system to act like the battery is dead. I mean when it does die the starter will try to turn over the motor but acts like the battery is low. That is why I tried an all new electrical box coil and all but still no luck though, as for an new rectifier; what the rectifier does is convert the low 12 v to a higher voltage for the pluges, so yes even though the rectifier could be causing the system to shut off, why would it cause the starter to not be able to turn the engine over unless I wait or remove the plugs? Just to give a little background to myself, I am an electrical engineer so I have some understanding of the system (at least the principle behind it) I really appreciate all the help you guys are providing .Thanks again

O yeah its Beaumont TX by the way, Also no one would happen to have an 97 XP MPEM laying around I could borrow to test my system with would they? lol
 
switch post

pull the post from the SPX and install to XP. See if problem is fixed., using the same landyard(xp landyard).
 
Tried new ground,and DESS post,no luck

Tried new ground,and DESS post,no luck, still dies after i run it for 4 min or so . What can it be AHAHAHAH! LOL

I noticed that when it does die and i pull the pluges that smoke comes from the cylinders,not a whole lot but you can definetly see smoke.Is that normal or not?

Also could this all steam from a bad mpem or not? Thanks
 
there's lots of smoke created in the combustion chamber, without the piston to force it out the exhaust, it will have some left over smoke. very normal.

I think the not turning over issue after it's warm is unrelated to the shut off problem. Instead of pulling the plugs, just turn the pto flywheel a little bit by hand past the high compression area and see if this helps.

checking the rectifier is simple, you'll know in 4 minutes if that is the problem. I've seen bad rectifiers do exactly what you describe, not exactly sure why they work for awhile perfectly then just wig out for a few minutes and then back to normal, maybe an internal heat thing from use? then they cool down a little on the inside and work again?

MPEM could be the problem but let's eliminate everything else first since they're not cheap.
 
I will try that.

Ok If I do turn the fly wheel and then it starts will this tell me that the rectifier is bad? I mean if so isnt that kind of the same thing as pulling the pluges turning the engine over then reinstalling the pluges and starting it? because right now that is what i can do to start it.I can also just wait a bit and it will start.Thanks for the help.
 
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I think it might be the rectifier.

I unplugged the rectifier and ran it on the hose for 5 min. I did not want to run it any longer that that but it never died, it also seemed to run a little smother. I am going to take it out on the river in the next few days and run it just on the battery for 10min and see what it does, I hope that is it. If it is I am still baffled as to why it would not turn over the engine, but o well. Thanks for the help. I will let yall know how it goes .Keep your fingers crossed.

I just got back from the river and it never died.I guess it is the rectifier.Now i need to get one.Thanks for all the help guys.
 
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