Craftsman No Start

[lefty]

So everything works now. I ran it for 20 minutes and it started first pull. Pulled it a bunch more times over the course of 5 minutes and it started first pull. The work I did was replace the coil and adjust the kill clearance.

But I'm still intrigued by BG's fly wheel concern. Should I still pull that nut off and take a look? I would imagine, and I'm probably wrong, that if the key was sheered the valve timing would be off. So my no start issue would be a random occurrence as the flywheels location in relation to the shaft would vary. But my no start issue was clearly isolated to a hot start situation. I don't mean to 2nd guess someone with so much more experience than me....just spit balling.

[bgsengine]

So everything works now. I ran it for 20 minutes and it started first pull. Pulled it a bunch more times over the course of 5 minutes and it started first pull. The work I did was replace the coil and adjust the kill clearance.

But I'm still intrigued by BG's fly wheel concern. Should I still pull that nut off and take a look? I would imagine, and I'm probably wrong, that if the key was sheered the valve timing would be off. So my no start issue would be a random occurrence as the flywheels location in relation to the shaft would vary. But my no start issue was clearly isolated to a hot start situation. I don't mean to 2nd guess someone with so much more experience than me....just spit balling.

Nah if you got it working now then its fixed -

Flywheel key can be just slightly sheared (very tiny bit - can happen just hitting a clump of grass) and throws off ignition timing (too advanced) resulting in incomplete combustion - symptom is a sooty spark plug - *sometimes* they don't shear enough to create a kickback (firing too soon) which is the classic symptom - but they can otherwise seem to run fine or seem to, but the timing will be off and performance suffers.

Flywheel key does NOT affect valve timing - just ignition timing - We have had many of those with identical symptoms to what you had described - they'd run a bit and then die - seemed to run fine but low on power, etc - and many many MZR cables replaced because they were worn or damaged so that they didn't pull the shut down lever far enough away from the kill switch.

[lefty]

Yes BG. Ignition timing. I feel stupid for saying valve timing. Ignition is what I was thinking and meant.

So assuming it is a cable issue, tell me if my thought process is wrong. When the safety handle is released, it grounds the circuit. When you depress the lever, you eliminate the ground. If the grounding connection is too close to the circuit while the handle is depressed, can the current jump the gap and ground out the circuit? That's what I was thinking.

[bgsengine]

Yes BG. Ignition timing. I feel stupid for saying valve timing. Ignition is what I was thinking and meant.

So assuming it is a cable issue, tell me if my thought process is wrong. When the safety handle is released, it grounds the circuit. When you depress the lever, you eliminate the ground. If the grounding connection is too close to the circuit while the handle is depressed, can the current jump the gap and ground out the circuit? That's what I was thinking.

Yes if the gap is small enough - Ever see how much of a gap simple static electricity built up on a cold day can jump? Especially if there's any extra conduction assistance such as moisture, dirt, etc - Remember, electricity follows path of least resistance - if the least resistance is jumping the gap of the shut off switch instead of grounding through the coil windings (inducing the voltage in the coil is the resistance) , it'll go direct to ground instead of through coil primary.

[KE4AVB]

Just wait until you get bitten by ungrounded kill terminal. Just repair FS85 that customer was tired of getting shocked.

[Fulltilt]

Flywheel key can be just slightly sheared (very tiny bit - can happen just hitting a clump of grass) and throws off ignition timing (too advanced) resulting in incomplete combustion - symptom is a sooty spark plug - *sometimes* they don't shear enough to create a kickback (firing too soon) which is the classic symptom - but they can otherwise seem to run fine or seem to, but the timing will be off and performance suffers.

Flywheel key does NOT affect valve timing - just ignition timing - We have had many of those with identical symptoms to what you had described - they'd run a bit and then die - seemed to run fine but low on power, etc - and many many MZR cables replaced because they were worn or damaged so that they didn't pull the shut down lever far enough away from the kill switch.

Have to say, never ran into that situation/symptom with a partially sheared key, mostly the usual " yank the rope out of you hand " deal, or just plain no start.

Yeah, the old stretched out zone cable is pretty common. Something you always have to check for, right?

[KE4AVB]

When comes to engine brake cables most my problems in the shop are from moisture entering the liner and corroding the steel cable causing it to seize in the liner. Only seen a couple where the liner was worn to the point it looks like the steel cable stretched.

Don't see many walk behinds anymore, just riders and handheld trimmers are coming into the shop in the last few years. So far this year it either been big JD ztrs or large 70+ cc Husqvarna chainsaws either of which has these cables.

[Fulltilt]

Yeah, that too, the water tends to lay in the belly/sag of the cable, then rust and bust.

[bgsengine]

When comes to engine brake cables most my problems in the shop are from moisture entering the liner and corroding the steel cable causing it to seize in the liner. Only seen a couple where the liner was worn to the point it looks like the steel cable stretched.

Don't see many walk behinds anymore, just riders and handheld trimmers are coming into the shop in the last few years. So far this year it either been big JD ztrs or large 70+ cc Husqvarna chainsaws either of which has these cables.

Actually by "wear" I wasnt talking about the liner (outer sheath) - those snap-in ones (pin and a rounded clip) tend to wear and weaken so that when the cable gets tight the pull of the cable "tilts" the snap-in end towards the bail handle, effectively shortening the travel of the cable. Then there's the ones that get kinked from folding the handles, or melted from being close to the muffler and they "scrunch up" a bit , again shortening the outer sheath and making the cable "stretch"

Cant tell you how many times we have had them come in with the clip-in end jury-rigged by fastening an automotive hose clamp or zip tie to try and fix it (which never lasts long)

sometimes all a no-start or "it runs and then dies" needs is a new MZR Cable.

[KE4AVB]

BGS , Don't forget that miracle cure all duct tape.