Loss of power on 200 opti

[tae73]

My motor has lost power it will not turn past 4500 rpms, it has 91 hours could a fouled plug causing this? It runs fine no smoke just doesn't come out of the hole like it should and no top end. Last week it run a little rough and I figured it was the gas becuase it sat for a month and had forgot to add stabil. I added stabil after last weekend and now this. Any ideas? Also it has seemed to of lost water pressure. No messages or warning showing up on the smartcraft guages. Also I drained the water seperator on the motor and had little to no water in it.

Also what should be engine temp be running wot?

[EuropeanAM]

WOT water pressure should be 15 PSI minimum (prefer 20 psi).

You won't be able to attain this, since you can't reach WOT.

Start with the basics- check spark on all six cylinders. Once you're certain you have spark on all six cylinders- Replace the spark plugs. Then see where you're at.

[tae73]

Don,

Do you think a loose spark plug could cause this problem? I found #5 was not tight at all and was several turns from being tight. This problem just started and the motor has 92 hours on it. Your thoughts?

[EuropeanAM]

A loose spark plugs is definitely an issue... and it definitely could affect your performance.

Since you're near the 100 hour mark anyway.... I'd go ahead and replace all the plugs now, then see where you're at.

Torque spark plugs WITH A TORQUE WRENCH to 20 ft. lbs.