Sea king 12hp losing cylinder

[jasonhowerton]

montgomery ward model #gg9016b

Motor started running with low power when I was on the water. So, I pulled carb and cleaned it. Checked the points and all the wires on coils. Everything looked good there. coils were new 2 years ago.Took it back out. It was worse running rough give full throttle and it would bogg down for 20 seconds or so then would surge to full power and run better, still not full power though like it was before. Brought it back home double checked points again thay are fine(.020). Plugs gapped .030. It is only running on 1 cylinder in barrel. If i pull the top plug no change, pull the bottom it dies. Could a coil have gone bad in just two years, or maybe a plug wire? or is there something I am over looking. Help is appreciated. Thanksconfused

 

[mrcrabs]

Re: Sea king 12hp losing cylinder

Try switching coils around to rule out the coils

 

[F_R]

Re: Sea king 12hp losing cylinder

You say the points are fine. Are you sure they are? If you are absolutely sure, then it is time to check the coil and spark plug wire. Check them for continuity. Also, the plug wires sometimes arc through where it is clamped to the armature plate. A tiny pin hole that you can't even see, sometimes.

You have tried a new spark plug----haven't you?

 

[jasonhowerton]

Re: Sea king 12hp losing cylinder

I switched the coils around and it ran better. still not the way it should. I was able to pull each plug and it made some difference in the idle. It would run on one plug or the other. When before i would pull one plug and it would not make a difference, and the other would kill it. ??? I switched it back to original and the exact same thing as before switching. Havent done a continuity test yet, I'm not sure how to do that. I can probably figure it out by searching other posts. Anymore ideas???

 

[mrcrabs]

Re: Sea king 12hp losing cylinder

Theres lots of youtube stuff on testing outboard coils.

 

[Tom @ Buzzard Bluff]

Re: Sea king 12hp losing cylinder

<I switched the coils around and it ran better. ---It would run on one plug or the other. When before i would pull one plug and it would not make a difference, and the other would kill it. ??? I switched it back to original and the exact same thing as before switching.>

So it ran on both cylinders when you switched the coils but returned to only one cylinder when switched back to the original configuration?

Sounds like a plug wire leaking to ground if that is the case. Try removing the clamping devices that retain the plug wires to the underside of the mag plate and inserting some thick insulating material between the wires and plate---something like a Popsicle stick should suffice--- and see how it runs.

 

[F_R]

Re: Sea king 12hp losing cylinder

You do a continuity test with a multimeter. You can get one at Wal Mart for under ten bucks.

Continuity test: Set the range switch on the multimeter to a suitable scale for the expected resistance. In this case, expect around 7 ohms. Touch one meter lead to the spring inside the spark plug boot and the other meter lead to the armature plate (magneto plate). Read the results. Should be several k-ohms. Don't get hung up on the exact number. But if it is very high resistance (like infinity or OL), there is a broken wire somewhere or a bad connection.

This test checks the coil, and wire at the same time. The parts can be checked individually the same way.

 

[jasonhowerton]

Re: Sea king 12hp losing cylinder

I think I Have it tracked down to the plug wire for on the top cylinder. I am having trouble figuring out where I can get a replacement wire from. Is it just a common aftermarket wire or do I need a certain number of wire. Please help. Thanks!

 

[steelespike]

Re: Sea king 12hp losing cylinder

Solid core spark plug wire(actually has copper wire inside ) not carbon impegnated fiber.Should be available at NAPA any well established outboard/small engine repair.
You local BRP dealer.