Motor wont get up to speed

[gen]

Crusing about 45 slowing down when the motor sounded like it down shifted,won't rev up in gear .Only goes about 15 mph swap out fuel line fuel pump ,fuel fill hose (was leaking) new plugs exsisting plugs looked good. Motor fires up easy revs up in neutral fine. found some loose wires on the switch boxes tightened them ran out to the lake ,no changes any thoughts or suggestions greatlly appreatated sorry it's 1985 Mariner ser # 6493543
150 hp carborated

 

[Chris1956]

Re: Motor wont get up to speed

Pump the fuel primer bulb, and see if it gets better. If so, rebuild the fuel pump. If not, start with the basics. Check compression, spark, plug condition/color... Post back

 

[gen]

Re: Motor wont get up to speed

checked compression today 105 -107 also has good spark. At first 2 cyclinders had no spark ,ran motor with muffs pulled plug wires off one at a time all had spark. a friend put a pico scope on switch boxes everthing looked good. noticed fuel filter was not full while running motor should this be full with no air space.If so would this cause problem? Replacing filter tomarrow trying it out at the lake under load . old filter was one of those glass kind it came lose some how. hopeing this is the problem.