CC 125 (K301) won't start - brilliant minds wanted

[dodgedoctor]

run a rire from pos post on battery to + post on ciol and try to start it .......sounds like bad ign switch

[eastonct124]

Originally Posted by Matt G.

jdubyk-

Aroostook is probably right. That's the most common failure mode of the switch, or at least it is in my experience. Replace the switch.

Eastonct124-

He says he's already changed all of those things several times. If the timing was off, he would still have spark. It would probably even start with the timing only 5 degrees off.

Hehehe, if I had a dime for every time I heard, "Yeah, did this, did that", then heard "You know, I checked it again , and you know I forgot about...."

I agree, hot wire the coil with a toggle switch inline......high probability that's the problem.
As far as timing...."Will probably start" doesn't fly in my book.

Close is only acceptable with Horseshoes, and Hand Grenades.

[jdubyk]

Whew,

Well, I spent some time on the mower yesterday and have restored the spark. The problem was two-fold. 1) the brand new points were permanently grounded. (defective unit) and 2) the spark plug was apparently defective as it snapped in half (right through the insulator) when I was taking it out of the motor.

So, I'm now back to where I started - i.e. the engine still won't start.

So here's what I've got/know:
- The timing is now right at 20d BTDC
- compression is excellent, valves fully closing and valve clearances are good
- still won't start using starting fluid

When trying to start, the engine mostly just stutters, occasionally backfires. With compression/timing seemingly perfect, I'm left to believe that it must still be an ignition issue rather than fuel since it won't fire on starter fluid. I guess I could try a fourth condenser??

-Jon

[Matt G.]

How are you timing the engine? Backfiring through the carb is a symptom of improper timing. If it has compression, is getting gas, and has spark, it'll start and run, but only if all of these things are introduced at the right time.

[jdubyk]

Checked the timing ny visualizing the flywheel markings at the instant the points open. Verified this with my multimeter while checking the continuity. In short, I followed your static timing instructions.
-Jon

[Matt G.]

Do you have spark on a spark plug? You actually have to pull a piece of paper through a new set of points to clean off the oil that keeps them from corroding before installation.

[eastonct124]

I'd check connections.....if you get an occasional backfire, that means occasional spark (normally)
You don't need a carb to start an engine....just alittle fluid shot in the cylinder, so yes, it has to be in the ignition sys.
Try jumper cables. One clamped to the block (bare metal prefered), put the plug in the other end.
See if you have spark......nice strong blue one.
If still no spark, hot wire the coil, with a toggle inline.
If it runs.....you've got a wiring problem. If not....could be coil.....could be coil wired backwards, could be points still bad.
It's not the space shuttle.
Take it one step at a time.

[jdubyk]

Thanks for all of the suggestions guys.

Matt G & eastonct124:

I do have spark at the plug, and I'm pretty sure it's all the time. If I hold the points open with a screw driver while I'm cranking the engine, the sound of the engine changes to like it's just pumping air. As soon as I release the points to function normally, that's when it returns to sounding like it'll almost fire. The occasional backfiring that I mentioned will happen during these times when I'm fiddling with the points.

I continue to ensure that I have spark by occasionally pulling the plug and laying it on the cylinder head. Althoguh, I would not describe the spark as a good strong blue spark. It's more of a white/yellow & I question whether this is good enough. I'll try to jumper the coil, directly from the battery this evening.

As for the oil on the points. I cleaned them right when I got them, and even took some 1000 grit sand paper to them to make sure there was good clean metal at the contact points.

[Matt G.]

You need a bright blue spark...the yellow-white spark is very weak, and there is probably little to no spark when it's in the engine. The engine's compression makes it more difficult for the spark to jump the gap, so a weak spark with the plug out of the engine will probably be nonexistent when the plug is installed in the engine. Is the plug gap correct? Also, you might try replacing the plug with a known good one...sometimes they are bad out of the box.

[jdubyk]

Problem solved: blown head gasket