Good time of year to go through your ski boat engines and components that make it run properly. Recently I pulled down a GT-40 that had been thoroughly abused. one of the complaints was it wont make power........Fuel Contamination is the biggest culprit in the ski world. Many a skier boat fails miserably because they refuse to practice good clean fueling. Commonly I see fuel cans on skiers docks with a rag or paper towel hanging out of the spout, or worse yet no cover at all sitting out in the rain and or dirt.
The fuel systems on these motors can only digest so much crap before the either clog up with debris or just rust up.

This Fuel system had no chance to be cleaned up and reused, Replacement can be costly. Keep you fuel practices sound and change your filters regularly!
And many skier's wonder why the tournament boat skis harder then their practice boat!
Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.
Comments
The best insurance is to not utilize dirty or contaminated fuel containers and get your fuel from a good clean source, stay away from the mom and pop gas stations even though these stations commonly have non ethanol fuel they tend to also be older storage tanks and do not cycle enough to be clean and free of contaminates. Utilize the bigger company's and utilize a quality brand such as Chevron/Texaco, Shell, Mobil ect. And check your fuel delivery system regularly!
I will also say that I've never seen so many people turn the nozzle up on their 5 gallon gas cans and punch a hole in the back without plugging it. Then they store all the gas cans on the garage floor. Cap it and seal it! If you lost the cap, a 1/2" pvc cap costs about 40 cents from the hardware store and fit perfectly.
Thanks for pointing these things out @jody_seal!!
Can I change out the FCC on my 2010 353 to a spin on canister. I have the inline filter as well. The filter on the FCC is $40 and a pain to change.
Eric
Marco, I think Preference is to change the oil before layup as then in the spring you know it has been done and ready for the season. oil will not degrade in the four to 6 month time frame of layup.
I also have a ECM for a GT40 with some electrical short on it somewhere.. if any "Radio Shack" guys want to pick this up cheap and test out the circuit board, that is up for sale as well. A new one is somewhere around $400 to $500 if I remember, $50 will get you a nice looking ECM with a short in it..
Not a mechanic but I play one at home