I have a 96 Johnson 130hp V4 looper and my motor runs at a very high idle at 1200 and lately surges to 1900 rpm's and can sit there for some time, then drop back down to the 1200's before going back up to the 1800 to 2000 range.
It's driving me crazy trying to track down the reason for the really high idle, so I'm hoping someone here could add some insight to a fix.
First off I am running my motor off of a 1 gallon gas can with the hose stuck in through the cap opening that is just a little larger than the hose. The reason for this is I just purchased the boat and the previous owner had mention he was doing premix in the tank along with using the VRO. So currently I'm in the process of taking the old gas out and cleaning the tank. I also disconnected the VRO so I can control the amount of premix being used.
My first questions is, could using the gallon can create the motor to run at a really high RPM by sucking in to much air? I've done this exact setup with my 2 stoke Yamaha and never had this high rpm issue, but this Johnson is a different monster.
2nd, I've checked for vacuum leaks and didn't see any, I have replaced my coils, plugs, and plug wires. I looked into the carbs and I can see the butterfly valve in all carbs have the same very small gap, not completely closed, but there is a 1/16" or less gap. I wouldn't think this small of a gap could cause the idle to take off to 2000 rpms could it? See picture below.....
3rd, I've back out the idle screw on the motor when it's at this high RPM and it does nothing, the engine continues to run high.
All suggestions are more then welcome ! Thanks all in advance...
Here you can see how much the butterfly valve is open...
It's driving me crazy trying to track down the reason for the really high idle, so I'm hoping someone here could add some insight to a fix.
First off I am running my motor off of a 1 gallon gas can with the hose stuck in through the cap opening that is just a little larger than the hose. The reason for this is I just purchased the boat and the previous owner had mention he was doing premix in the tank along with using the VRO. So currently I'm in the process of taking the old gas out and cleaning the tank. I also disconnected the VRO so I can control the amount of premix being used.
My first questions is, could using the gallon can create the motor to run at a really high RPM by sucking in to much air? I've done this exact setup with my 2 stoke Yamaha and never had this high rpm issue, but this Johnson is a different monster.
2nd, I've checked for vacuum leaks and didn't see any, I have replaced my coils, plugs, and plug wires. I looked into the carbs and I can see the butterfly valve in all carbs have the same very small gap, not completely closed, but there is a 1/16" or less gap. I wouldn't think this small of a gap could cause the idle to take off to 2000 rpms could it? See picture below.....
3rd, I've back out the idle screw on the motor when it's at this high RPM and it does nothing, the engine continues to run high.
All suggestions are more then welcome ! Thanks all in advance...
Here you can see how much the butterfly valve is open...
Last edited: