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I have an old Toro 521 snowblower (model # 38056) with a Tecumseh 5hp engine (not entirely sure exactly which model, possibly 640084B). This winter, while happily blowing the snow, it stopped and hasn't started since. Usual culprit is crap in the carburator but that seems fine and it won't even start on ether (which it always used to do even when the carb wasn't carbing). It has good compression and seemingly some kind of spark (plug visually looks decent and there is a spark), but it doesn't fire at all no matter what I do. I think I noticed one single successful combustion when messing with it, but that's it. My best guess is to throw a new plug in, and failing that, a new coil. I have no way of telling how "good" the spark is, but an old crappy coil or some such is the least bad guess I have as to why it would stop working suddenly like that. Is there anything else I should be checking out on this thing? It's maybe not the snowblower I want but it's the one I deserve, and I'd just like to keep it running until it is clearly dead beyond rescue. It needs a new pull starter (and a replacement carb just because cheap and easy), which I'd really only want to do if I can get the engine running first.
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May 3, 2023 14:55
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| # ¿ May 13, 2024 14:51 |
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Hadlock posted:Fuel air spark I had just the "naked carb" on there and with fresh gas in it (had it drained and cleaned first just to make sure that wasn't the culprit again), and tried it multiple times with engine starter spray stuff (not sure if it's ether or what, but it has always made the engine go when it has had carb issues). Which to me seems like not a fuel issue. Fuel, air, compression and spark all seem to exist, but the bastard still won't run. I can't say for sure how good the spark is though. It is there, but maybe it's just not angry enough? wesleywillis posted:Has there been a loss of compression? I checked with a compression tester when I had the plug out, forgot the exact number but it seemed perfectly normal and generally sounds like an engine with compression when I crank it (since the pull starter is broken, I've been using a power drill which spins it decently fast, and would reliably start it back when it worked). It is a flathead, yes (haven't pulled the head off, but it sure looks like one). If the cam gear was stripped, wouldn't that cause poo poo compression if things had gotten out of sync? Given there's many months until I'd expect any snow, maybe I just gotta pull it apart and see if I can find brokenness (and if it's hosed enough just get a new machine).
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May 4, 2023 10:06
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wesleywillis posted:If the cam gear stripped, or broke or whatever while the valves just happened to be closed then it might give decent compression numbers while cranking. I'll probably take it apart enough to fiddle with the ignition coil (I'm assuming it's a magneto because derpy simple engine), and if that doesn't help, keep wrenching deeper until I find something suspect. Stripped cam gear would probably mean a new machine (parts are likely unobtainium here), but ignition stuff seems simple and cheap enough to replace. I'd just rather not pull apart stuff I don't need to, since while no gaskets/seals seem to leak right now I'm sure they will be more than happy do so after the sealing surfaces see daylight for the first time in decades. MrYenko posted:By “naked carb” you mean you had the carb blown apart and rebuilt, right? I just meant I had no air cleaner or anything on it, but the whole carb has been taken apart and cleaned a couple of times (including now, even though I'd done it recently I wanted to be sure that wasn't it). I didn't remove all the little pressed-in bits, but I've cleaned out all the jets/needles/channels that screw apart or where it's possible to blast carb cleaner and compressed air and poked thin wire through the tiny holes. Carbs are loving dark magic to me, though this one seems just barely comprehensible and as far as I can tell seems alright (though it certainly wasn't when I bought it). If I can make the engine run on ether I might replace the carb just because it's dirt cheap to do, and some parts seem a bit worn out (mangled screw heads and some slop in the choke/throttle levers and such).
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May 5, 2023 11:29
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