[bostonpilot]

I'm stumped and could use some ideas from the group. I have a 1991 15hp Mariner. At the end of last season, it started running like crap. The only way to get it started was to shim the throttle open adn once it started, it seemed like it was only running on 1 cylinder.

Over the winter, I started the troubleshooting and thought I had fixed verything up, but it won't start at all now and I have run out of ideas.

The work over the winter was:

-Checked for spark on each cylinder. Found one cylinder was getting weak or no spark (using a spark tester)
-Swapped wires from electronic switch box to coils. No spark cylinder followed the wire. i.e. switch box was dead

-Therefore, replaced switch box

-After replacing the box, check both cylinders with spark tester and they looked like they were getting good strong sparks

-Did a full carb cleaning and rebuild kit

-New spark plugs

-New fuel filter

-Kill switch on the tiller was getting very flakey. Replaced switch assy

-Also, as part of the annual maintance, replaced the therostat, lower end oil, impeller and did a general cleaning.

Tried starting the motor for the first time since all of this work today and it wouldn't go. A few symptoms - if I prime (overprime?) using the chock lever, the first few times I tried to start it, it almost seemed like a partial backfiring happened. Other than that, there was absolutely no indication that the motor wanted to start. I tired every combination of choke, no choke, throttle position, etc. Also, tried a few squirts of starter fluid into the card air intake in desparation - no luck.

So, now I am questioning everything, including my sanity. I'd love any ideas, theories, etc that you guys have.


Thanks in advance!

[bostonpilot]

A follow-up question/theory - I don't think this is the case based on the lengths of the wires from the switch box to the coils, but stranger things are possible.

If I had accidently swapped the wires to the coils, so the switch box is telling the wrong coil to fire, would you expect the above symptoms? Also, can you come up with an easy way to determine if this is what I did?