Suzuki 25 HP Oil Injection - One Cylinder not firing - coughing and stalling

[krisrf]

Good day,

I recently picked up a Suzuki 25 HP Oil Injection 2 Stroke engine - I think its around a 93. With that said, it suffers the following symptoms:

- Idles as long as I want, but if I put it in gear and keep the throttle low, it stalls after seemingly coughing
- Checked over the fuel line from tank the motor, all is good. Primer bulb is good.
- See a bit of gas floating away from the back of the boat
- Pulled the cover, checked the spark plugs with the following results:
- Look new as in probably replaced end of last season
- Top two have blackish soot on them, thus indicating they are firing
- Bottom one is crystal clean - looks like it has never fired, though it did have some gas on it.
- Motor seems underpowered, but I'm not used to these motors

I suspect that the big red flag is the bottom spark plug, but what are my next steps in dealing with this issue?

Cheers!

Kris

 

[krisrf]

Re: Suzuki 25 HP Oil Injection - One Cylinder not firing - coughing and stalling

Good day,

I have now found the problem and will fix it tomorrow when I can get the supplies I need. It turns out that the bottom spark plug wire was shorting out on the bolt on the cover. When we take the cover off the engine runs fine. If you hold the spark plug wire and pull the rope you often get a shock through the boot). Everything else is good though.

Kris