chadtoolio
Recruit
- Joined
- Jul 31, 2013
- Messages
- 2
Hello all,
I have scoured the internet, including threads here, done lots of checking on the motor and also done some parts changing.
2001 Boston Whaler 13, 2001 Mercury 40hp 2 stroke, 2 cylinder carbureted engine. The idle is very rough and when on part throttle when coming off idle in a no wake zone you can feel the cylinder(number 1 presumably) "kick" back in. Also, it takes a very long time to plane off with more than just one person in the boat.
I did a compression check on this motor before I bought it and also today. 140 psi on both cylinders. I have checked and cleaned the fuel filter and carburetor(removed, disassembled and re-installed). I have checked and adjusted the throttle linkage, fast idle and throttle cables. I have checked the ignition timing at idle. I have replaced both ignition coils and wires.
Here's what I do know....
You can remove the #1 spark plug wire, short it out and run the motor and it is very consistent running. If you remove the #2 wire and run the engine, the idle is just as choppy as when both are connected, obviously with one less cylinder. Swapping the coils, or spark plugs makes no difference. I have looked for a schematic online so that I can look at patterns with the O-scope but cant find any. The BMW's and MINI's I work on have only a 3 wire coil (power, ground, and signal). These are 4 wire, so I am confused as to what Mercury is trying to accomplish with what wire.
I am all for the easy answer, this cant be the first one doing this and my pride wont let me replace anymore un-necessary parts, so I need some help on this.
Thanks, Chad
I have scoured the internet, including threads here, done lots of checking on the motor and also done some parts changing.
2001 Boston Whaler 13, 2001 Mercury 40hp 2 stroke, 2 cylinder carbureted engine. The idle is very rough and when on part throttle when coming off idle in a no wake zone you can feel the cylinder(number 1 presumably) "kick" back in. Also, it takes a very long time to plane off with more than just one person in the boat.
I did a compression check on this motor before I bought it and also today. 140 psi on both cylinders. I have checked and cleaned the fuel filter and carburetor(removed, disassembled and re-installed). I have checked and adjusted the throttle linkage, fast idle and throttle cables. I have checked the ignition timing at idle. I have replaced both ignition coils and wires.
Here's what I do know....
You can remove the #1 spark plug wire, short it out and run the motor and it is very consistent running. If you remove the #2 wire and run the engine, the idle is just as choppy as when both are connected, obviously with one less cylinder. Swapping the coils, or spark plugs makes no difference. I have looked for a schematic online so that I can look at patterns with the O-scope but cant find any. The BMW's and MINI's I work on have only a 3 wire coil (power, ground, and signal). These are 4 wire, so I am confused as to what Mercury is trying to accomplish with what wire.
I am all for the easy answer, this cant be the first one doing this and my pride wont let me replace anymore un-necessary parts, so I need some help on this.
Thanks, Chad