Check your fuel pickup tube in the tank it may be stopping up and not drawing enough fuel. Good luck
In post #14 of this thread, I posted an image of a Volvo Penta AQ200 "B" engine w/ a Sherwood belt driven seawater pump.
Pull the plugs, Take a picture of them and post it.......lay them in order of cylinders when the pic is taken...
They should all look pretty
not sure of the brand but it is 1.8 mts wide and 3.8mts long , 0.65mts deep.
Nope. No pic