1998 90hp merc serial number 06664299

[Cherokeert]

Hello
Today I tried to start my 90 hp merc after it had sat since last September. I charged the battery, pumped the bulb, disengaged the throttle and advanced the throttle about 1/3, pushed in the key for a count of three and turned the key to start while holding the key in the choke position and heard an immediate pop followed by a fast crank but no sputter or catch. Tried this process two more times without success. I bought this boat last year and only had it out 4 times and have always had trouble getting it started and keeping it running until after it warms up. Any suggestions? Also, after trying to get it started I noted what appeared to be a leak but it didn't smell like oil or gas. Pictures attached. Should I be concerned
Thanks

[JOE54]

mtr has lot of fuel leaking into crank case, that's coming from exhaust, suggest complete fuel system cleaning and repair, pay close attn to oil check valve bad about leaking oil into fuel line flooding system with pure oil, hope this helps ya JOE

[omykee]

Joe,, could your suggest what the original pop mite have been ? Kinda like a back fire... Thanks..

[JOE54]

fuel built up in cyl ignighted when sparked