2005 Mercury 50 ELPTO running rough....

[PSG-1]

I'm wondering if anyone can help me figure this out.

Bought the engine new in 2009 (it had sat at the boat dealer's lot for a couple of years)

Once it was running, it was fine, but starting it is another issue. It's always been a PITA to start, but recently, it was getting worse.

So, I changed the spark plugs, it still had the factory plugs in it. After I changed the plugs, it cranked right up, but when I go to hit the throttle, it acts like it's running on 2 cylinders, or it's starving for fuel, I can't figure it out. Takes forever to get up on plane, and it's not reaching max RPM.

I'm wondering if I somehow pulled a spark plug wire loose from its connection in the boot when I changed the plugs. That's the only thing I can figure, because, like I said, it was running fine before I changed the plugs, other than the issue with hard starting.

Any ideas?

 

[jonboatsam]

my Name is Sam and Have been a Marine tech since 1972, Ill try and help you! One thing to try to see if it is ign or carb problem give it full throttle and hit the choke for a sec or 2 and see if the power comes back if it does its a fuel related problem if it doesnt most likely ign problem or a weak cyclinder.
Sam

 

[PSG-1]

Disregard my previous post....I got it fixed! Man, do I feel like an idiot.

Since I suspected it was a problem with ignition, I pulled all 3 plugs, connected the wires to them, and grounded them out on the block, to do a quick check for spark.

While removing the plugs, I noticed that all 3 of them were fairly clean, but the center one was pure white, so, I knew that cylinder wasn't getting fire, but I double checked by turning the key for just a second....sure enough, no fire.

I tried pushing the wire into the boot a little better, then realized they are molded, so, I knew it hadn't come loose. OK, maybe it's a bad coil......

Well, when I looked at the center coil, I noticed that the delphi pin connector plug was loose, I could see the seal. So, I clicked it back in place, then checked for fire again by hitting the key. Bingo!

Installed the plugs, and it started right up, and runs as good as ever.

I don't know how I managed to accidentally disconnect the coil wire when I changed the plugs, but in any case, I'm glad it was something minor and I got it figured out!