Geez, This Is New. Has Me Baffled.

[LawnCzar]

SloMo Lawn Addict! I very well may owe you a beer or two? I believe I do.

Reading your posts, and noticing the message you have at the end in RED (part of your signature?), at the very least had me thinking. My motor did seem a bit excessively hot. Started wondering if that extra heat stopped the electrical system to energize the spark plug, and when it cooled off, allowed a spark again? Just a thought. So this morning, with thorough determination, remove that upper shroud and gave everything a good cleaning. I`d post a before picture, but I am too embarrassed to. Nothing short of horrible. Shop vac, brushes, rags and 2 hrs later I have a clean engine again.
Before I tried starting, checked for spark, with plug out of the cylinder. Yes, got spark again. Put back in and fired up in 1/2 a second. Don`t remember it doing that, that quick in years. Immediately felt the cool breeze of the fan coming up thru the top of the motor. Damn! What the hell was I thinking? And, finnished cutting for the long weekend.
Though I always do simple maintenance and keep records of hrs and dates for oil, filters, tires, repairs, ....... This air flow maintenance check is essential. Just stupid of me not to realizing it until I read your message. I won`t forget the lesson I learned. Just hope nothing got damaged from this.
Thanks again!

 

[slomo]

You dirty bastard LOL. Just kidding, playing with words. 2 hours cleaning the block? I want pictures damn it. No I DEMAND them LOL. Would of loved to see it before you spent all that time cleaning. WOW...... Glad to hear she is slaying grass again.

In your first post you said you gaped a plug out at 0.040"? Is that the factory gap? Just checking. Sounds rather wide for a mower.

Again on the cooling fins. For an engine THAT filthy, power washing the block and head/s gets a pass in my book. Then and only then though. Water gets were it doesn't belong. I would spray all the electrical parts and connections with WD-40 (water displacing). Definitely hit it with compressed air, blow nozzle and SAFETY GLASSES. Clean the block and fins like a new engine, down to bare metal. I'm not really a fan of painting the engine either.

Remember this goes for ALL air cooled engines.

If your engine is really working, you might of dodged tossed valves, valve guides walking out, rockers falling from home and such. Shows how tough these little engines are. This is real when I said engine damage. Dump the oil a couple times and you should be good.

I would double check the head bolt torque. Thanks for coming back and letting us all know your resolution.

 

[LawnCzar]

1st pic right side - after cleaning / 2nd pic right side - after cleaning. air shroud tight to cooling fins / 3rd pic right side - before picture with loosened shroud.
Well, in my meager defense, after reviewing all my original manuals and owner`s documents, I found nothing in there about cleaning out the back end of the motor (I gotta check again). But something I noticed only after I cleaned and reassembled everything and felt the strong breeze of the cooling fan coming up thru the top side of the motor. This `Shroud` that inevitably is holding in all the debris, abuts the motor very tightly (1st & 2nd pic). The design is obviously to allow the fan to blast the backside of the motor without any escape of air until it hits the motor and is channeled up and around the cooling fins.
There was little evidence of this clogged air flow due to the tight shroud. But once I loosened the top part of it (3rd pic), I new I had to take a bunch more of it completely off. I have kept my mower garaged for the 28 years I have had it. Since moving to PA 12 years ago, sometime in the last couple years, stored in my basement, guessing a mouse made a nest in there. Plus, had dirt caked on the cooling fins. Hence, 2 hour cleaning. I got a huge percentage of dirt off the fins with multiple brushes. But may dig deeper at another point as I did not remove the actual fan enclosure. But, I didn`t see anything in there from my view point.
Nevertheless, the machine ran better than it has in a long time. Gonna change the oils/filters next go around on schedule.

But if it were`nt for that warning signature of yours, I ??MAY?? not have discovered the problem behind that `SHROUD` ! And yes, everyone must be aware of it, whether in the manual or not.
Thanks again!
PS - The spark plug gap is .040 per my manual. It does seem excessive as it is the thickest on my gap tool.