Weird problem

[mstrijbos]

Since two weeks i experience a very strange problem with my 96 XP.
When taking it from the trailer everthing is fine, the toy starts, and runs.
After a short while (in the water) the engine does not rev up anymore (only a litte), when i stop and start the engine 10/15 times, the problem some times dissapears. I noticed that when i ride during this problem (full trottle but limited revs) and i play with the trim buttons, the engine starts revving a bit?

Can anybody please help?
Regards, Mike

 

[nswillin]

You probably have a fuel problem. First thing I would do is check the spark plugs, just in case their all fouled up to be sure, sometimes it's something small like that. If everything looks good there, check to see if you have the old gray fuel lines. Replace them with black fuel injection rated hoses. As you are changing out the lines make sure to clean the selector valve real good also. The carbs have little filters in them as well that will need to be cleaned out. That should get you started. :cheers:

 

[kustomkarl]

Chances are your engine is low on compression. If it runs better on land and while playing with the trim allowing it to rev up for a short time, due to lack of extra load on the impeller, is a sign of low compression. Do a compression test, Here's how;

You'll need a compression tester. Go to Auto Zone. I think they sell for like $25.00. The compression gage, will screw in the cylinder head in place of the spark plugs. To test compression, remove both spark plugs. Place spark plug caps on the plug cap studs near the cylinder head to ground the empty caps. This completes the circuit of the ignition electrical system and prevents any electrical problems from the caps being un grounded. Using the correct adapter for the threaded end of the tester,( same length of the spark plug threads length)screw in the tester in one plug hole. Hold the throttle wide open. Push the start button. Watch the compression gauge, when it peaks out at the most compression, let go the start button. Read the psi number. I would do it 3 times to be sure it is accurate. Check both cylinders the same way. The ideal compression is 150 psi per cylinder. If it is less, it's not a problem as long as they are close to being the same. If the psi is less than 90 it might need be time for a tear down and a rebuild. If the psi in 1 cylinder is say 140 psi and the other is 80 psi you need to tear down and repair. This difference is a lot then there is a problem. I hope this helps you.

Karl