2004 115hp slows after warms up

[paulgar56]

After running at 5500 rpm engine slows to 4000 rpm and shakes. If I remove cowl engine runs fine.
What would cause this?
Thanks Paul

 

[bobbyc]

Check for an exhaust leak somewhere under the cowl. Check for plug wires grounding out on the cowl...running the engine at night might help locate any leaking spark voltage.

 

[MIDNIGHT EXPRESS]

Ive heard when the engine is mounted high the exhaust tuner or base gasket blows out. any feedback guys?????