mustanghorizon
Seaman Apprentice
- Joined
- May 7, 2016
- Messages
- 38
Hi all,
I have a 1996 Johnson 115 (J115SLEDR) that was running great at the beginning of the season. A couple days ago it began to run pretty poorly, only hitting about 5000 RPM at WOT and surging, almost like it was starving for fuel. The boat normally runs at close to 6000 RPM at WOT. I have checked many things as I have been through a similar event before, but this is different with the surging. I just completely went through the carburetors, all jets and orifices were clear as well as the gaskets in great condition. I checked for water in the fuel, which was negative. All four cylinders have compression of 130 PSI. All four have spark. Plugs are newer and look good. Pumping the priming bulb at WOT does get rid of the surging, but no increase in RPM. I am leaning towards a weak fuel pump. I took the fuel pump apart and all of the orifices are intact with no obvious deformities. This is a VRO pump, which I still have connected. When the problem began the boat also began to smoke a little more than usual. I am thinking that the pump is not drawing enough fuel, and therefore it is receiving more oil causing the rich condition. I have tested for an air leak on the boat side of the fuel line, and everything seems intact. Does anyone have any ideas? Thanks in advance.
I have a 1996 Johnson 115 (J115SLEDR) that was running great at the beginning of the season. A couple days ago it began to run pretty poorly, only hitting about 5000 RPM at WOT and surging, almost like it was starving for fuel. The boat normally runs at close to 6000 RPM at WOT. I have checked many things as I have been through a similar event before, but this is different with the surging. I just completely went through the carburetors, all jets and orifices were clear as well as the gaskets in great condition. I checked for water in the fuel, which was negative. All four cylinders have compression of 130 PSI. All four have spark. Plugs are newer and look good. Pumping the priming bulb at WOT does get rid of the surging, but no increase in RPM. I am leaning towards a weak fuel pump. I took the fuel pump apart and all of the orifices are intact with no obvious deformities. This is a VRO pump, which I still have connected. When the problem began the boat also began to smoke a little more than usual. I am thinking that the pump is not drawing enough fuel, and therefore it is receiving more oil causing the rich condition. I have tested for an air leak on the boat side of the fuel line, and everything seems intact. Does anyone have any ideas? Thanks in advance.
