Engine dies on Polaris 700

[Manateeoncruise]

I do have the following problem with my Polaris Jetski Marine 700 LE:
It starts up after several tries, it accelerates to high RPM, but when you throttle back to idle the engine dies. Idle seems to be a little rough.
The carburator has been cleaned. I have not been able to measure the compression of the engine (no tester) but took the heads off and looked at the cylinders. Both look fine to me.
We checked both spark plugs when start difficulties occured - they are wet. Hence we do not suspect a fuel problem.
We cleaned the air filter.
Last option we can think of is the ignition.

Does anyone has experience with the ignition box or the above described problems? Any ideas?

Thanks for help!

 

[bigdaddypt]

Re: Engine dies on Polaris 700

First off...make sure the battery is fully charged.

Three things need for the engine to run...compression, fuel, spark. It sounds like you have compression but you can always do the thumb test. Put your thumb over the spark plug hole and crank it over. It should blow your thumb off the hole. Next, take the plugs out and one at a time, put it in the boot and lay the plug and boot on the head and crank it over and look for a nice spark on each plug. Make sure the plugs are good and clean. If you don't see a nice spark, try cutting the zip tie on the boot, unscrew the boot, cut back about 1/4 of an inch of the plug wire, screw the boot on, zip tie it and try again. If you still don't see a nice spark, then it is a spark issue.

However, my money is on a fuel problem. While the carbs might be "cleaned" as you said, they still might need to be rebuilt. You can have the cleanest carb gaskets and diaphrams in the world, but if they're old and stretched, it'll still run like crap. It also might be the fuel pump needs to be rebuilt. Do yourself a favor. If you try the compression and spark test and those are ok, then you want to rebuild the carbs and fuel pump, and probably replace all the fuel lines, clean the selector valve and replace the water separator and put in a new oring. Also take the fuel baffle off and clean the screen at the bottom of it. This will basically give you a fully rebuilt fuel system that will have the ski running great for a long time and will prevent other, more serious issues...like your engine blowing up.

Report back after you do those tests.

 

[Manateeoncruise]

Re: Engine dies on Polaris 700

Thanks for help - will be back when done!