If i prime the carbs the motor starts and runs good, i can shift into gear (with muffs) runs great, as soon as i take it out of gear it dies and i have to prime carbs to run again. Motor sat for 15 years in a garage on a 1960 starcraft 16' boat. put new plugs in good gas, ran sea foam thru the carbs. ?????? seams like it runs out of fuel when i take it out of gear.