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GT 40 question

seveetseveet Posts: 37 Baller
Last week we started developing an issue with the check engine light coming on when we brought the boat back to idle after a ski run. Initially it would flicker. Eventually it just started to stay on. Turn the engine off and back on- everything was fine. Oil pressure did read a little low at around 20 at idle around 40 under power. Today we had the same issue. The only thing that was different is the the engine kicked into limp mode while running under power for about 2 minutes even though the check engine light didn’t come on. Seems like it probably is an oil pressure sensor issue. The only thing that throws me is what happened today. Am I missing something?


  • TomHTomH Posts: 64 Baller
    You're likely on the right track with the oil pressure switch. There's only 2 things that will throw the GT-40 into limp mode - oil pressure and water temp (assume your water temp was ok through this all).
  • jhughesjhughes Posts: 1,123 Mega Baller
    Simple way to tell if that's the issue- simply unhook the lead for that sensor. An open circuit is "everything's OK" for that circuit. Same with the water temp sensor, unhook to bypass.
  • Jody_SealJody_Seal Posts: 3,375 Mega Baller
    It's the separate green wire single connector on the back of the engine next to the main engine wire harness. Un hook it..
    Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.

  • seveetseveet Posts: 37 Baller
    Yes it was the oil pressure switch. Through me for a loop at first as I disconnected the green/blue wire that goes to the sender. Had both wires off and still was having an issue. The switch was the brown wire closer to the motor that comes of the T. Once I disconnected that, everything ran great. Thanks
  • 6balls6balls Posts: 5,788 Mega Baller
    There are two oil pressure sensors on the '40. One feeds the check engine light and triggers limp mode, the other feeds the guage on the dash.

    My check engine light/limp mode failed, but the guage read normal...was like "what?" Disconnected the sensor that feed the CEL and the limp mode and no problem to finish the season just watch the guage as always. Replaced the sensor in the off season and reconnected everything.
    Dave Ross--die cancer die
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