My TT 250D was starting and running fine through the srping and early summer. But, the last two weekends it won't start. It cranks just fine but doesn't seem to fire at all - like there is a spark problem. It has been very humid (90-100%) many days here in MN over the last month and I'm thinking something is getting moisture. That seems to be confirmed because we brought it home this past weekend on the trailer - i.e. exposed to lots of moving air - and when I backed it off it started right up. But a couple of hours later - in 98% humidity - it went right back to not starting. So we figure it must have dried out on the way home so there was a little window where it fired off but then back in still, humid air it went right back to the problem. Yesterday was much nicer - lower temps and humidity, but still no luck.

So two questions
1. Does our diagnosis sound right? 2nd, 3rd,...nth opinions welcome.
2. Assuming it's a moisture problem, where do I look and what can I do to aleviate it?

Thanks for any advice.

 

i would test your on off switch, key, and safteys first make sure they are working when this happens. then move on to cdi and coil. when this happens have u pulled plug to confirm a no spark?

 

I don't think it is the key switch because it turns over and all the lights work fine. Unless it is a separate keyed connection not related to the starter.

I'll check the kill switch. Maybe that is being closed somehow with the humidity. I've heard the kill switches on these chinese quads can be quirky. Anybody find the need to bypass the kill switch because of issues?

I haven't pulled the plug yet but I'm just assuming no spark because of the way it is acting. Plus it did start when it was "aired out", so I know that the plug itself and the spark plug wire are ok, generally speaking. I think the problem is upstream of there.

My neighbor thinks coil. I would think coil and cdi would be sealed and not greatly affected by simple humidity. But maybe I'm wrong. Any way to test that theory out? Is there a way to "dry out" those components?

 

Check for a healthy spark when the fault is on before going any further. The coil and HT lead are the most likely causes of electrical problems due to moisture but water condensing in the fuel tank is another consideration, so make sure your problem is electrical.

 

You could always relocate to Arizona or Nevada..

Id start with the coil..

 

Assuming for the moment that it is the coil. Any way to dry it out? Maybe with my compressor air nozzle?

 

I'm no mechanic. So help me through "Check for a healthy spark when the fault is on".

 

I would leave it in the sun all day.. maybe on the dash of a car.

A healthy spark is a blue spark..

 

Unplug the rubber spark plug cap, remove the spark plug from the head, plug the rubber spark plug cap back on the spark plug, touch the threaded part of the plug against the engine head or any good ground and try cranking the engine as you were and look for a spark. Don't touch the metal end of the plug while doing this, you could be mildly shocked. Good luck!