Beta marine 75 starting problem

[sector steve]

Hello there I hope this is the right area of the forum to post this. I have a beta Marine 75 hp that has been sitting for 3 months in El Salvador. She is having some trouble starting. And when you turn the key for five or so seconds you get a knock while turning over but not fire. Trying to knock this out here any advice would be greatly appreciated. Thank you

 

[Boater Sam]

A "Knock" when cranking is very worrying. Could water have entered the engine via the air inlet or the exhaust?
If this is a raw water cooled engine, with water out with the exhaust, long cranking without it firing can draw water into the engine from the exhaust elbow.