Ox66 Spark Plugs - No Gap?

[GregGuimond]

My 1999 250 Ox66 was running great for a 50 mile run. Had topped of the fuel before leaving to the very top and burned through 2/3 of the tank. When returning to the boat for the return leg there was 1/3 tank left. Started the boat and seemed rough, would only go to 3500 RPM. Stalled a couple of times and blew off a ton of smoke on restart. Got home on fumes with nothing left in the tank at all. Was ready to check the O2 but pulled the plugs first to inspect. The sparkplugs at the TOP of the left and right bank had "no gap" left while the other 4 plugs were gapped to spec. Top two were closed, and could just slide a piece of paper through there. All plugs were black but not wet.

Any feedback appreciated......very strange

[Stratos21XL]

The first thing I would do is a compression check on the two cylinders the plug gap was closed up on, and while I had the plugs out I would look at the top of the pistons for marks. I hope the pistons weren't hitting the plugs causing the gap to close.

[skeeter202]

time for hydro tec I am afraid , sounds like pistons hitting plugs . look at top of pistons . motor may be salvageable if it did not lock up . hopefully I am wrong but that is sure what it sounds like