hi got 83 bayliner 125 aq volvo.found cracked exhaustmanfold.motors very hard to start hot or cold.wont idle if dropped back at throttle below 1500 rpm,stumbles then stalls.if put in gear wont accelerate.will out of gear .motor feels rough when running.not a misfire more like loading up.just recently had electronic conv.done for starting prob.cant ck timing with timing light as eng stalls first.know it ran ok last year.plan on manifold replacement but need to fix others problems as well. thanks for any help .ernie