Re: Mercery 9.8 stalls only with lid on only.
Look at the cover as someone might have changed it out with a cover from a diffrent year notor and the one you have dose not have the needed air vent space that was on the motor when new. You might have to drill air holes in the lower cowl pan to get the needed air for the motor to run right. Check for fuel leaks as it might be flooding out if there is to much fumes in the enclosed motor also.
JMO
Oldman570
