1982 merc 90 hp inline. I just recently developed a real rpm lag out of the hole I took my 21 pitch prop off(which was fine before)and replaced with my ski prop which is a 19 and usually launches the boat right out of the water.I pumped the primer ball while engine was struggling and the rpms shot right up great. Any ideas befor i start tearing into it ? remote tank,clean gas, clear line,working vent<br />thanks<br />dave