original plugs

Hi guys, I bought a 1999 smoker craft that has a 1999 merc force motor on it. The boat and motor look like new, I took it out for the first time yesterday and and fished and played for a couple hours. I noticed at full throttle i was going 28 mph i could fill a slight hesitation for a split second about every 10 minutes or so but it was very slight and hard to notice. I started just putting along the bank fishing (which sucked) for half hour or so and the same thing would happen it would hesitate just enough to make motor shake a little. When i decided to head back to dock it would only go 10 mph I stopped and checked the plugs. The top one fouled out so i limped it back to the dock. The plugs that are original (i could tell by the paint that was on them that they had never been changed since motor was painted) are champion l76v which dont have center electrode. I have heard pros and cons on these plugs is this what i should replace them with or is there something better. Thanks

Start with a compression test.

2 or 200 hp what is the serial number of the motor?

OOPs sorry it is a 40 HP

Do a compression test and a spark gap test first just to know first but if original plugs the motor must not have alot of hours on it. Champions are normally good for two seasons but allways best to at least replace the plugs yearly. Although the paint could be from some cosmetic work done to pretty up the motor for sale but sounds like a fouled plug to me. The spark must jump a gap of at least 7/16 inch open air gap with a brite blue snap.
champion QL76V

Thank you kimcrwbr1 I just did a compression test 120 - 125 on both cylinders I bought boat from original owner and im totally confident the motor has had no work done to it. I would bet anything these are original plugs. I did test top plug for spark and no spark. Good spark on bottom plug. I took good plug and tested in top cylinder coil and it has good spark there so im ruling out coil as well. I Thinking it is just a fouled plug is all. I just have been reading on line that those plugs were designed for high rev high speed motors. I was wondering if there was a different plug i should be running or just stick with the champions. I do know a guy can read anything on the internet thought LOL. The plugs are L76V. I see you listed QL76V not sure what the Q is Thanks for all the help...

Sounds like you need to replace the impeller also just to know it is good, you dont want to burn up what sounds like a sweet deal.

The surface gap plugs can last 10years or more.

The "missing" could be water in the fuel?
Or a bad reed behind the carb?
Only at high speed could be the clutch dog?