We've been chasing a motor issue for a few months now. My 1995 Mercury 2.0L 150 hp carb motor will not rev over 2000 rpm and if it does get on plane it falls at least 500 rpm short of the usual WOT 6000 rpm (there have no prop changes, etc., before this started)
This condition first appeared right after I decarbed the motor (following the directions on the can of Power Tune) through the carbs on the first trip back at the lake. I replaced the fuel filter, bulb and line to the motor, fuel coupler, fuel pump diaphragm and made sure the fuel tank vent was working properly.
My mechanic (good guy) has replaced every electrical ignition component (VR's, stator, trigger, switch boxes) with no change after each component was installed. Compression and leak down tests were also done with all cylinders at 125-128 psi (cold) and the carb synching is correct
I believe now decarbing the motor loosen debris which has blocked the high rpm jets, passages, etc. in one or more of the carbs. Checking the main jets they were clear and there was no apparent debris visible. My mechanic states since the motor fires right up, idles very smooth and shows no evidence of any carb issues it's not a carb issue. I disagree and think the carbs should be disassembled completely cleaned since all electrical parts of the old "spark or fuel" theory have been eliminated.
The "long winded" question are the carbs at fault? I've owned the boat since February 07 and I don't know the maintenance history and up to when I performed the decarbing it ran great. I have since tried decarbing motor again but with no change.
Any thoughts would be very helpful and possibly solve our debate. I have read on several message boards of the same symptoms and the leading fix has been the other owners trading or selling "the problem..."
This condition first appeared right after I decarbed the motor (following the directions on the can of Power Tune) through the carbs on the first trip back at the lake. I replaced the fuel filter, bulb and line to the motor, fuel coupler, fuel pump diaphragm and made sure the fuel tank vent was working properly.
My mechanic (good guy) has replaced every electrical ignition component (VR's, stator, trigger, switch boxes) with no change after each component was installed. Compression and leak down tests were also done with all cylinders at 125-128 psi (cold) and the carb synching is correct
I believe now decarbing the motor loosen debris which has blocked the high rpm jets, passages, etc. in one or more of the carbs. Checking the main jets they were clear and there was no apparent debris visible. My mechanic states since the motor fires right up, idles very smooth and shows no evidence of any carb issues it's not a carb issue. I disagree and think the carbs should be disassembled completely cleaned since all electrical parts of the old "spark or fuel" theory have been eliminated.
The "long winded" question are the carbs at fault? I've owned the boat since February 07 and I don't know the maintenance history and up to when I performed the decarbing it ran great. I have since tried decarbing motor again but with no change.
Any thoughts would be very helpful and possibly solve our debate. I have read on several message boards of the same symptoms and the leading fix has been the other owners trading or selling "the problem..."