150 4-Stroke Mercury Outboard w/190 hrs on a Tracker 20'
Intermittent missing problem.... I live on Watts Bar Lake which is part of the TN River and generally joy ride for a couple of hours at a time cruising around 3500 RPM.
SYMPTOMS:
The motor starts and runs perfectly, then after cruising for a period of 30 ~ 60 minutes, the engine will begin to miss and sputter. To resolve the missing, I'll do one of two things; come to a stop idle for a while, then continue OR go full throttle for 30 seconds. Either stopping or accelerating seems to resolve the issue and the motor runs great again perfectly for another 30~60 minutes. Again, very intermittent, sometimes the motor will run great for 2 hrs, other times will begin missing twice in an hour. I've never tried just continuing on while it was missing sputtering to see if it corrects itself, the missing is too unsettling for me to do that.
WHAT I'VE TRIED: Note that since this is intermittent, I wanted to gather observations before taking to dealer.
This has been going on for over a year so I've tried several things. Initially it seemed that when missing it was starving for gas. I installed a clear in-line filter in the fuel line going into the engine so I could watch fuel flowing. Fuel flow did seem to diminish as the engine began missing. I observed that opening the gas cap would allow fuel flow to return to normal as observed in the clear in-line filter. The gas cap has 4 valves that is part of emissions system and keeps pressure as gas inside tank expands and contracts with temperature changes. I thought that if the valves in the cap were not working and not letting any air in there could be a condition that when the gas was being consumed, a vacuum would build that restricts fuel from flowing. I tried removing the valve assembly from the cap (one screw) so that no vacuum would build but same condition exists but not as frequent.
Replaced in-line filter within the motor itself.
Replace spark plugs
Different gas; been going on for over a year and 100 hrs so have gone through a lot of gas from different sources.
Took the boat to the dealer and provided my written observations and things tried. Dealer was not very helpful.... dealer immediately suggested my problems were caused by the external clear in-line gas filter I installed. Further suggested that in order to provide warranty work, they may need to replace external gas line with a replacement thus eliminating the external filter. I was obviously irate and complained to the salesperson whom I purchased a pontoon boat from that month and evidently suggested to service to overlook my inline filter. But, the service guys couldn't identify the problem, said they didn't see any errors while reading the ECM. Admittedly, the intermittent nature of the problem would be difficult for the service department to observe.
The motor is beyond its 3-year warranty so trying to resolve myself. I replaced the valve assembly in the gas cap, but symptoms continue as before; runs perfect for 30~60 minutes, starts to miss a bit, then runs great.
Any suggestions would be greatly appreciated.
Intermittent missing problem.... I live on Watts Bar Lake which is part of the TN River and generally joy ride for a couple of hours at a time cruising around 3500 RPM.
SYMPTOMS:
The motor starts and runs perfectly, then after cruising for a period of 30 ~ 60 minutes, the engine will begin to miss and sputter. To resolve the missing, I'll do one of two things; come to a stop idle for a while, then continue OR go full throttle for 30 seconds. Either stopping or accelerating seems to resolve the issue and the motor runs great again perfectly for another 30~60 minutes. Again, very intermittent, sometimes the motor will run great for 2 hrs, other times will begin missing twice in an hour. I've never tried just continuing on while it was missing sputtering to see if it corrects itself, the missing is too unsettling for me to do that.
WHAT I'VE TRIED: Note that since this is intermittent, I wanted to gather observations before taking to dealer.
This has been going on for over a year so I've tried several things. Initially it seemed that when missing it was starving for gas. I installed a clear in-line filter in the fuel line going into the engine so I could watch fuel flowing. Fuel flow did seem to diminish as the engine began missing. I observed that opening the gas cap would allow fuel flow to return to normal as observed in the clear in-line filter. The gas cap has 4 valves that is part of emissions system and keeps pressure as gas inside tank expands and contracts with temperature changes. I thought that if the valves in the cap were not working and not letting any air in there could be a condition that when the gas was being consumed, a vacuum would build that restricts fuel from flowing. I tried removing the valve assembly from the cap (one screw) so that no vacuum would build but same condition exists but not as frequent.
Replaced in-line filter within the motor itself.
Replace spark plugs
Different gas; been going on for over a year and 100 hrs so have gone through a lot of gas from different sources.
Took the boat to the dealer and provided my written observations and things tried. Dealer was not very helpful.... dealer immediately suggested my problems were caused by the external clear in-line gas filter I installed. Further suggested that in order to provide warranty work, they may need to replace external gas line with a replacement thus eliminating the external filter. I was obviously irate and complained to the salesperson whom I purchased a pontoon boat from that month and evidently suggested to service to overlook my inline filter. But, the service guys couldn't identify the problem, said they didn't see any errors while reading the ECM. Admittedly, the intermittent nature of the problem would be difficult for the service department to observe.
The motor is beyond its 3-year warranty so trying to resolve myself. I replaced the valve assembly in the gas cap, but symptoms continue as before; runs perfect for 30~60 minutes, starts to miss a bit, then runs great.
Any suggestions would be greatly appreciated.