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1997 seadoo xp 787 will not start

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buckmaster4

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I recently put new valves , rings and gaskets on my 1997 seadoo xp 787 put it all back together and it will not start. It has excellent compression,lots of fire and its getting fuel.Is this perhaps a timing issue ? If so how do you time it ? I've tried everything please help..Thanks
 
Did you verify that your rotary valve is spinning, and that it's timed properly?

If you have compression, fuel and ignition... it should run.
 
Thats what I'm thinking too tony..It should start but it dont..where is the rotary valve located and how do you check the timing ? Thanks for your help...
 
Did you verify that your rotary valve is spinning, and that it's timed properly?

If you have compression, fuel and ignition... it should run.

Thats what I'm thinking tony..it should start..where is the rotary valve and how do you check to see if its spinning? also how do you check the timing ? Thanks
 
The rotary valve is towards the bottom side of the motor below the carbs. Timing the rotary valve is pretty easy and you can find the information in this forum. I just printed out the timing wheel and set it up per the instructions. To actually adjust the timing of the spark, I believe, requires a programming tool that is quite expensive. The last one I saw was going for $1200 on ebay. I don't believe there is any other way either.
 
If you had all this stuff apart and did not disturb the coils the timing should be fine, the rv mostly makes air come out of the carbs, you can remove the rv cover and slowly turn the crank using the driveshaft to see the disk turning, if this is all good, then reset the disk with the degree wheel process and you should be good. Your description of fire is spark? the pressure should be 150 but most important is within 10-15 lbs of the other one, fuel is where? and how old? pour a coffee shop spoon of premix into each plug hole and retry starting after you get the rv timing set.
 
Thanks voodoo..I didnt disturb the coils at all...I'm new with these waverunners just bought them and never owned 1 before..getting to the rotary valve is that the black cover on the sliding valve that you are talking about removing ?The spark plugs have lots of fire(Spark) and there is fuel on the plugs when I remove them...Fuel is new..As far as resetting the disk with the degree wheel process I dont understand what you mean by that..Can you please be a little more specific..I'm totally lost on this thing..Thank you very much for your help..
 
Rotary Valve location and Resetting

The rotary valve lives between the intake manifold that your carburetors are bolted to and the crank case. You must remove the carbs and the rotary valve cover (the manifold) to get to it. Before you do that, make sure you rotate the crank so that the MAG side piston is at TDC (can verify by putting a pencil or screw driver inside the spark plug hole and watch it rise/fall) Once you position the MAG piston all the way up and remove these carbs and manifold DO NOT REMOVE THE ROTARY VALVE ITSELF. The rotary valve is a flat stainless stell disk with about a 150 degrees cut-out. Do a goodle search to see what it looks like. Once you can see the rotary valve, you can check to see if it's set properly.

What I did was print out the degree wheel http://www.seadooforum.com/showthread.php?t=12763, glue it to some cardboard (like a cereal box) and cut it out, being most careful on the inner circle, as this is what fits over the rotary shaft. Next, I carefully cut 40-50 degrees out of the wheel starting at 360, so that you can align it with the bottom of the MAG side intake port. At this point, the degree wheel should look something like the picture that should have uploaded with this post. Next I placed the degree wheel on the rotary shaft OVER the rotary valve itself, aligned degree wheel with the bottom of the MAG intake port and made sure that the rotary valve was aligned with the 147 degree mark on the degree wheel.

The other check related to the rotary valve is the rotary valve clearance. This is to make sure the rotary valve has the proper amount of room to rotate without binding or being too loose. To check this, you have to use rosin-core solder. There is a method described in the online manual where you crush the solder by placing two half inch pieces of it on the rotary valve (using grease to hold it there while you put on the manifold) and reinstalling the intake manifold without it's gasket. Torque the mani down to spec, then remove. The solder should have gottne squished to .010 to .014 inches. I used a micrometer to verify the thickness of the crushed solder, but I think there is another method using solder of a certain thickness that doesn't require a micrometer.

I hope this helps.

Andrew
 

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