I have a Johnson 3.5 HP thats 10 months old.<br />It will run at WOT for 15 - 20 mins, but after a restart will not stay at WOT for the rest of the day. RPM fluctuates between WOT, and then dies by about 2000RPM and then picks up again. It then cycles like this getting steadily worse. Topping up the fuel does not help either.<br /><br />Dealer has tested in a tank but it won't recreate the problem.<br /><br />Its not air starving because taking the cap off at WOT doesn't stop it.<br /><br />Sounds like fuel to me as the tank reduces below half. I am surprised it is doing this straight out of the box, but the dealer says nothing is wrong with it.
<br />I had a similar sounding problem. It turned out to be a split in the gas pickup tube in the remote tank. As soon as it got to half a tank it would sputter & run bad, but it never died completely. <br />If you fill up the tank does the problem go away?