nwpete
Cadet
- Joined
- Jul 7, 2017
- Messages
- 17
My Mercury 40hp 2 stroke (2001) won't stay idling and I really need an advice as to what could be wrong with it. Let me provide you with all the facts. I have also attached a video of it dying while it idles for about a minute (sometimes shorter).
- The outboard keeps idling when I push the "choke/enrichment" button before it's about to die by pressing the key in. Yes, it's an electric start. When I press the key in, the engine starts revving higher in rpm for a bit and returns to the normal rpm and then the engine dies.
- I have cleaned the carburetor (WME 2XK) very thoroughly. I used a carb cleaner, air blow gun and a piece of wire to clean out all the jets and holes. They didn't seem blocked but I made sure anyway. Before I cleaned the carb, I noticed that it was actually very clean without any varnish or gum. I properly set the float per my Mercury Repair Manual. Replaced all the gaskets and the needle.
- I doubt it's the fuel pump and here is why. The engine keeps running so long as I push the choke button. Also the primer bulb stays firm and the fuel filter stays full of fuel while running the engine. I can see the fuel level in the semi-transparent fuel filter canister. Also, keeping pressing the primer bulb, which is already almost firm does not prevent the engine to die.
- After starting, when I push the throttle lever up in neutral position, it still dies. So probably no IAC issue?
- It dies even if I use fresh fuel. Whatever is in my old fuel tank is only about one or two months old.
- There is fuel in the carb bowl when I unscrew the nut.
- Possible fuel hose blockage? When I press the primer bulb in the beginning, it fills the fuel filter right up so I don't feel there is any blockage from the fuel tank to fuel filter. After the engine dies, when I unscrew the carb bowl, enough fuel spills out so I don't think the hose from the filter into the carb is blocked either.
It sure sounds like a classic blocked carb jet issue, but I swear the carb is clean and EVERY hole and jet is unblocked. So at this point, I really have NO idea what's wrong with this thing.
- The outboard keeps idling when I push the "choke/enrichment" button before it's about to die by pressing the key in. Yes, it's an electric start. When I press the key in, the engine starts revving higher in rpm for a bit and returns to the normal rpm and then the engine dies.
- I have cleaned the carburetor (WME 2XK) very thoroughly. I used a carb cleaner, air blow gun and a piece of wire to clean out all the jets and holes. They didn't seem blocked but I made sure anyway. Before I cleaned the carb, I noticed that it was actually very clean without any varnish or gum. I properly set the float per my Mercury Repair Manual. Replaced all the gaskets and the needle.
- I doubt it's the fuel pump and here is why. The engine keeps running so long as I push the choke button. Also the primer bulb stays firm and the fuel filter stays full of fuel while running the engine. I can see the fuel level in the semi-transparent fuel filter canister. Also, keeping pressing the primer bulb, which is already almost firm does not prevent the engine to die.
- After starting, when I push the throttle lever up in neutral position, it still dies. So probably no IAC issue?
- It dies even if I use fresh fuel. Whatever is in my old fuel tank is only about one or two months old.
- There is fuel in the carb bowl when I unscrew the nut.
- Possible fuel hose blockage? When I press the primer bulb in the beginning, it fills the fuel filter right up so I don't feel there is any blockage from the fuel tank to fuel filter. After the engine dies, when I unscrew the carb bowl, enough fuel spills out so I don't think the hose from the filter into the carb is blocked either.
It sure sounds like a classic blocked carb jet issue, but I swear the carb is clean and EVERY hole and jet is unblocked. So at this point, I really have NO idea what's wrong with this thing.