Hello I have a 1988 Johnson GT 165 model number J175stlccm. My problem I'm having is at higher RPMs there is a fuel starvation. Things I have done so far.
Replaced VRO pump(mixing 50:1)
Checked Pulse Limiter
Replaced spark plugs
Rebuild carbs
Replaced primer bulb 3/8 from tank to motor. I've tried 3 different ones.
Replaced all fuel lines in motor
Replaced inline fuel filters
Checked tank vent. Have ran motor from a portable take with same problem.
Replaced water pump
Checked Spark
I have also done a decarb on the motor it needed it pretty bad.
Checked compression 75PSI across all cylinders.
Took apart VRO pump and inspected and tested per testing procedure. Tested good.
I have 2 clear inline fuel filters installed. One before the VRO pump and one after pump before it goes into the carbs.
When running on muffs I can watch the gas being pumped into the fuel pump filter stays fuel. The filter after the pump gas is being pumped into in but filter never gets full even at idle. But motor never stalls. Once I but motor in water and under load. Same thing idles great can run motor up using the cold start gas flow increases from pump never stalls. When it's in gear up to about WOT throttle about time boat wants to get up on plane it just bogs and dies out. I can manually pump it to keep it running somewhat but doesn't help much. I know the fuel pump gets its pulse from the crankcase but I can't find any problems anywhere.
Replaced VRO pump(mixing 50:1)
Checked Pulse Limiter
Replaced spark plugs
Rebuild carbs
Replaced primer bulb 3/8 from tank to motor. I've tried 3 different ones.
Replaced all fuel lines in motor
Replaced inline fuel filters
Checked tank vent. Have ran motor from a portable take with same problem.
Replaced water pump
Checked Spark
I have also done a decarb on the motor it needed it pretty bad.
Checked compression 75PSI across all cylinders.
Took apart VRO pump and inspected and tested per testing procedure. Tested good.
I have 2 clear inline fuel filters installed. One before the VRO pump and one after pump before it goes into the carbs.
When running on muffs I can watch the gas being pumped into the fuel pump filter stays fuel. The filter after the pump gas is being pumped into in but filter never gets full even at idle. But motor never stalls. Once I but motor in water and under load. Same thing idles great can run motor up using the cold start gas flow increases from pump never stalls. When it's in gear up to about WOT throttle about time boat wants to get up on plane it just bogs and dies out. I can manually pump it to keep it running somewhat but doesn't help much. I know the fuel pump gets its pulse from the crankcase but I can't find any problems anywhere.