40hp stalls @ WOT (intermittent though) ???

Hi,
early 90's 40HP Mariner, oil injected, electric start.

This motor has been bomber for a long time but just recently...after WOT it will stall instantly like it looses spark or fuel. This doesn't always happen everytime at WOT. Sometimes it wouldn't come right back to full RPM's, just putter around, and then it would catch...next day full RPM though. Had boat out first time this year with new plugs and same thing...then it ran good after a couple stalling episodes.

It always starts right after with a little bit of idle high...and a way we go.

My question is this a wonky ignition issue with it loosing spark, could fouled plugs cause this, or is fuel starvation/vapour lock issue? Thks in advance,

Re: 40hp stalls @ WOT (intermittent though) ???

sounds as though spark COULD be the problem but would be a loose connection IMHO. My guess is that more likely would be a fuel starvation problem. If there is a filter, or maybe water in the gas, or a chunk of crud in a small jet in the carb.

Re: 40hp stalls @ WOT (intermittent though) ???

bump, any other suggestions. thks