Hello all and thanks in advance for any assistance you can provide. I apologize for the length of this. A little recent history with my 1999 3 cylinder. I've had the assistance of a retired boat mechanic thru all of this.
Early this year - difficult to start, might fire off once after hour or two of trying. Removed from slip, took to mechanics shop. Carbs removed, cleaned, fresh gas, kill switch bypassed, put back in water, still no fire, mechanic replaced ignition switch, still no fire. Replaced CD unit, started right up, ran a little rough at idle (replaced plugs) and ran fairly well at full throttle but still wouldn't run out at what I would call full speed (5000+ rpm).
July 4 weekend - Took boat out and ran up to full throttle (would only get to 4500 rpm) for about 100 yards and engine started running extremely (violently rough, shook the boat) (like it had dropped a cylinder) but after 30 seconds it straightened up but repeated this cycle consistently for over an hour until I returned to slip. Mechanic suggested a coil pack may be cutting out once hot so I ordered one. In neutral, engine revs fine and up to 6000+ rpm with no issues. Doesn't seem to exhibit the same condition as when under a load.
This week I replaced each coil one at a time until I went thru each coil and there was no change in performance.
I run only no ethanol gas. I've spent several hundred dollars this year. I've owned this motor and the pontoon boat it's on for 10 years. Getting close to the point of finishing life out without a boat. Very frustrated.
Early this year - difficult to start, might fire off once after hour or two of trying. Removed from slip, took to mechanics shop. Carbs removed, cleaned, fresh gas, kill switch bypassed, put back in water, still no fire, mechanic replaced ignition switch, still no fire. Replaced CD unit, started right up, ran a little rough at idle (replaced plugs) and ran fairly well at full throttle but still wouldn't run out at what I would call full speed (5000+ rpm).
July 4 weekend - Took boat out and ran up to full throttle (would only get to 4500 rpm) for about 100 yards and engine started running extremely (violently rough, shook the boat) (like it had dropped a cylinder) but after 30 seconds it straightened up but repeated this cycle consistently for over an hour until I returned to slip. Mechanic suggested a coil pack may be cutting out once hot so I ordered one. In neutral, engine revs fine and up to 6000+ rpm with no issues. Doesn't seem to exhibit the same condition as when under a load.
This week I replaced each coil one at a time until I went thru each coil and there was no change in performance.
I run only no ethanol gas. I've spent several hundred dollars this year. I've owned this motor and the pontoon boat it's on for 10 years. Getting close to the point of finishing life out without a boat. Very frustrated.
