Rusty Olds
New member
I have a 2006 4.3L Mercruiser with a TKS Carby. The engine was new when I bought the boat and had been fitted by the dealer. The engine has just over 500 hours on the clock and has run well throughout. I service the engine annually in September which includes a new fuel filter change. I now have have an issue that is driving me mad.
I started the boat normally and idled out the channel before opening up the throttle and cruising for 20 minutes, when I brought the throttle back to idle the engine died and would not restart. I pulled off the flame arrestor and notice fuel dribbling down the Carby throat, without the engine running. I suspected a stuck needle and seat and an over full float bowl. I opened the throttle wide and cranked to clear, the engine starting after a while. I was able to keep the engine running at about 2000 rpm. I motored back to the dock without slowing down, the engine again died as soon as I went back to idle at the dock. I let it cool and removed the Carby top, cleaned out a little crud and cleaned out the needle and seat. After reassembly I restarted the engine and it ran until it warmed up after which it died again with fuel dribbling down the throat. So I suspected a bad needle and seat and I ordered a Carby kit.
when the Carby kit arrived I fitted a new fuel filter (replacing the 3 month old previous filter), cleaned out the Carby, cleaned the Venturi block, replaced the needle, seat and float then reset the float level. I restarted the engine normally and my problem appeared to be solved. We ran the boat for the week and put about 10 hours on the engine before it started having issues again. I pulled the top of the Carby again and checked for issues, all looked fine. While there I reset the float level so that the fuel would be about 1 mm below normal fuel level. I restarted the boat and we ran it for an hour without issue before again having fuel dribbling down the throat. So now I’m starting to think that the problem must be elsewhere with the only thing coming to mind being the fuel pump.
questions
could the electric fuel pump be putting out too much pressure thereby forcing the float down to overfill the fuel bowl?
is anybody aware of issues with these fuel pumps?
does anybody have any other ideas as I don’t just want to throw money into a new pump uselessly.
oh before anybody responds, note that it has a fresh tank of fuel and we don’t need to worry about wintering our boats here. Winter here gets down to a chilly 6 or 7 degrees C. It is summer now of course.
I started the boat normally and idled out the channel before opening up the throttle and cruising for 20 minutes, when I brought the throttle back to idle the engine died and would not restart. I pulled off the flame arrestor and notice fuel dribbling down the Carby throat, without the engine running. I suspected a stuck needle and seat and an over full float bowl. I opened the throttle wide and cranked to clear, the engine starting after a while. I was able to keep the engine running at about 2000 rpm. I motored back to the dock without slowing down, the engine again died as soon as I went back to idle at the dock. I let it cool and removed the Carby top, cleaned out a little crud and cleaned out the needle and seat. After reassembly I restarted the engine and it ran until it warmed up after which it died again with fuel dribbling down the throat. So I suspected a bad needle and seat and I ordered a Carby kit.
when the Carby kit arrived I fitted a new fuel filter (replacing the 3 month old previous filter), cleaned out the Carby, cleaned the Venturi block, replaced the needle, seat and float then reset the float level. I restarted the engine normally and my problem appeared to be solved. We ran the boat for the week and put about 10 hours on the engine before it started having issues again. I pulled the top of the Carby again and checked for issues, all looked fine. While there I reset the float level so that the fuel would be about 1 mm below normal fuel level. I restarted the boat and we ran it for an hour without issue before again having fuel dribbling down the throat. So now I’m starting to think that the problem must be elsewhere with the only thing coming to mind being the fuel pump.
questions
could the electric fuel pump be putting out too much pressure thereby forcing the float down to overfill the fuel bowl?
is anybody aware of issues with these fuel pumps?
does anybody have any other ideas as I don’t just want to throw money into a new pump uselessly.
oh before anybody responds, note that it has a fresh tank of fuel and we don’t need to worry about wintering our boats here. Winter here gets down to a chilly 6 or 7 degrees C. It is summer now of course.