My friend has a mercruiser 5.7L 350. He just pulled it out of storage. He changed the oil and fuel filter. The boat starts great (just changed the starter) and idles fine. In neutral the motor will rev fine and sounds good. No missing or backfire. The problem is when it is in gear. At WOT the boat takes off, planes out, then loses power. Almost down to an idle. Leaving the throttle wide open results in the boat eventually taking off, then losing power, then take off, then lose power... You get my drift. There is still no missing or backfire. I thought that it could be bad fuel. He only had 5 gallons in it when he stored it. Then he put 20 gallons more in. After he had the issue he added some dry gas. He let it idle for about an hour then took it back out and the issue is even worse. Temp and voltage look good. The trans is only two years old and the fluid looks good. Does anyone have any idea what the issue could be? I checked the vacuum lines and they look good. The spark arrester is clean. The plugs look like it may be running a little rich. Thanks in advance for your help!
