K341 with weak spark

MFP8055 · #1 01-03-2010, 01:40 PM

My 1650 shut down while I was warming it up to plow yesterday. It just barely fired up and then no spark. I disconnected the Kirk ignition module, and tried the standard points/condenser set-up. Both are brand new. I checked the resistance through the coil and it's close to spec. The plug wire might have had a break so I replaced it with what I had available which was an automotive wire. This probably has higher resistance for radio noise suppression but it's what I had. What I'm seeing is a weak, intermittent spark. Yellow in color, and not enough to get the engine to even cough. Fuel is good and timing is also.

It's around 10 degrees (F). Could the coil still be a problem even though it checked out OK? Any thoughts?

Rhoderman · #2 01-03-2010, 02:37 PM

Check your 12V supply. Is the battery low, or have a dead cell?

If the battery seems okay, try running a wire directly from the coil + side to the battery + side and see if that helps. That would quickly rule out the connection from the battery, to the switch, to the coil. No need to remove the old wire since you're essentially paralleling it.

The coil also has to have a good ground, as does the battery. Check the battery minus, and where it attaches to the frame. Make sure the engine is well bolted to the frame. Disconnect the cable and scrape the metal and put it back together.

Hope this helps.

Yosemite Sam · #3 01-03-2010, 03:04 PM

Rhoderman,

Is exactly right, try the hot wire to the coil.

The other thing is to check your grounds.

Do you have a ground wire from the frame to the motor? If you don't, you probably should have.

MFP8055 · #4 01-03-2010, 05:26 PM

I'm getting a good 12.8V at the positive coil post. I re-routed the engine ground cable, and still have a weak spark. Compression seems OK just by pressing my thumb over the spark plug hole. It's hard to believe that it won't even cough a little. Even when the timing was off you'd get backfire or something. Starter fluid had no effect either, and it doesn't take much to get that stuff to burn. What are the symptoms of a bad coil. Mine checked out indoors, but it's cold outside. I'm really grasping at straws right now.

OZCUB 123 · #5 01-04-2010, 05:55 AM

I'd do a volt drop test stick you multi meter in parallel from the positive on the bat to the positive of the coil and crank any reading over 0.5V and you have too much resistance in that circuit plenty of volts but no amps

Matt G. · #6 01-04-2010, 10:26 AM

Quote:

Originally Posted by OZCUB

I'd do a volt drop test stick you multi meter in parallel from the positive on the bat to the positive of the coil and crank any reading over 0.5V and you have too much resistance in that circuit plenty of volts but no amps

This is basically the same thing as he just did. He said he's got 12.8V at the coil + terminal, so he doesn't have any drop.

MFP8055-

Is the spark plug new and/or gapped correctly? That's about the only thing you haven't checked yet.