Need Input

[WGM]

2007 20v Marine Power 340hp. Cruising at 30mph. Temp,oil press good. Heard a sound. Found breather tube off of valve cover. Put tube back on. Took a few for boat to fire up , seemed like motor was loaded up so cleared it out. Idles fine But a now blows white smoke ( smells like fuel ) like I said idles fine Until under load the rough with white smoke. Fouled plug ? Please don’t say head gasket. Oh ya oil seemed fine. Not milky or watery. Help

[Thegerman618]

unlikely its the head gasket, not impossible but very unlikely usually that's going to be a result of overheating. Might just be steam from the exhaust and running a little rich. Not to much cause for concern as long as all the temps are where they should be. Been in many brand new boats in colder water that steamed pretty good and ran a little rich. I had a 06 24Ve with the MP340 and in cold water it would blow some steam from time to time if i had it loaded up with full ballast but wouldn't do it at idle. I think your probably fine, but someone else may have an idea.

[boatwakes]

Extra fuel in the exhaust would also cause it to feel loaded up so there's possibly a stuck or leaking injector. We've replaced more injectors this past year than I can count. Do a fuel pressure test first and then shut off the engine. If the pressure holds then the injectors are most likely not the problem. However I've seen pressure regulators allow the fuel pressure to go in excess of 80 psi which causes the same running issues. So run the engine with the pressure tester attached and see if the fuel pressure maintains while its running. Should be around 40psi. If it climbs and doesn't stop, pull the regulator on the fuel rail and clean the screen. Keep us posted.