OldSkoolFloater
Cadet
- Joined
- May 21, 2021
- Messages
- 9
Hello all. My 1977 Johnson 115HP outboard is giving me the blues. It is model 115EL77S. Lets start with the history.
I bought it as a project 4 months ago. Previous history unknown. Is on a 18" bass boat. Replaced head gaskets, rebuilt carbs, new fuel pump, new impellor and housing, new primer bulb, cleaned out gas tank, new spark plugs, one new coil, all spark jumps 7/16" gap, new power pack. Will start with muffs on and accelerate fine. A little hard to start after warm. Compression is all cylinders at about 115.
BUT, in the lake starts and will idle fine. Start to accelerate and it dies. Spraying ether into the air intake as you accelerate makes no difference. But, if you choke the engine it pushes past the problem within 300 rpms and can run at full throttle all day long.
Thus, I see the idle circuit seems to be working, and the jets are flowing at high speed. It seems to be a carb problem to me. I am wondering, is there a specific carburetor mounting wherein the bottom carb is possibly mounting at the top and causing the issue? A jetting issue?
Boat runs at about 40-45mph when on the lake. Can do a couple of laps and is fine. Drop it back down to idle and try to power back up and it dies.
I'm at a loss. Does anyone else have a solution I haven't thought about? The carbs seem correct from images I have seen. There were really clean when I opened them up.
I bought it as a project 4 months ago. Previous history unknown. Is on a 18" bass boat. Replaced head gaskets, rebuilt carbs, new fuel pump, new impellor and housing, new primer bulb, cleaned out gas tank, new spark plugs, one new coil, all spark jumps 7/16" gap, new power pack. Will start with muffs on and accelerate fine. A little hard to start after warm. Compression is all cylinders at about 115.
BUT, in the lake starts and will idle fine. Start to accelerate and it dies. Spraying ether into the air intake as you accelerate makes no difference. But, if you choke the engine it pushes past the problem within 300 rpms and can run at full throttle all day long.
Thus, I see the idle circuit seems to be working, and the jets are flowing at high speed. It seems to be a carb problem to me. I am wondering, is there a specific carburetor mounting wherein the bottom carb is possibly mounting at the top and causing the issue? A jetting issue?
Boat runs at about 40-45mph when on the lake. Can do a couple of laps and is fine. Drop it back down to idle and try to power back up and it dies.
I'm at a loss. Does anyone else have a solution I haven't thought about? The carbs seem correct from images I have seen. There were really clean when I opened them up.
