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I've been gifted a 12.5 HP / 33" craftsman snowblower, and can't get it to run right. The only way I can get it to idle is to play with the screw on the bottom of the carb (which has a spring). When it's wound out enough that it'll start & idle it backfires frequently, out the exhaust and the intake. It also started pissing gas out the vent tube, and the oil is full of gas, at which point I stopped loving with it and cleared the driveway with the old one that starts every time. With the screw at the bottom of the carb wound in farther it simply won't start. It seems like the only way it'll run is with waaay too much fuel going in, and I don't know where to go from here (other than change the oil before anything else). It ran before it was moved to my house, but was drained of gas (and refilled on arrival with non ethanol fuel). I'm wondering if bouncing around on a moving truck messed up the carb somehow. What should I do next? E: model # Craftsman C950-52113-1. I've found a manual for a C950-52113-0, which I'm assuming has the same engine - it's a Tecumseh 12.5hp 4 cycle model 143.021203. TrueChaos fucked around with this message at 21:53 on Dec 5, 2019 |
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Dec 5, 2019 20:53
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| # ¿ May 9, 2024 23:57 |
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Will do. Found the part number from the manual and a new one is only 30CAD on amazon shipped to my door. I'm going to grab that as well, so that I can throw it on and take apart/reassemble the bad one as a learning experience.
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Dec 6, 2019 05:22
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Are you sure it's not overfilled with oil? It'll foam if there's too much, because the crankshaft is whipping around in the top of the oil.
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Apr 29, 2020 16:52
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Dealing with a snowblower that when I stopped loving with it last, it would: -Start, with lots of effort, sometimes. It ran like poo poo. -Lots of gas in the oil. -Die immediately under any load, occasionally backfiring out the carb. I took the carb off and cleaned it out. Changed the oil, etc. Added a fuel shut off valve, as I figured the float wasn't seating correctly and allowing fuel into the cylinder while it was sitting, which was then leaking around the rings and into the oil. I also replaced the spark plug. Now, it won't start at all. Doesn't even begin to catch. The carb has fuel, and I do have spark. I can watch the carb and see that it's pulling fuel into the intake as it's turning over, and that fuel is added with the priming bulb. I think there's a valve or timing issue - I'm getting puffs of air out the air inlet side of the carb. My understanding is this would only occur if the intake valve is open or not properly seated during the compression or exhaust strokes. Pulling the spark plug and putting my finger over the opening, I can feel suction, but not a huge amount of pressure. Is there any other reason that I'd be getting puffs of air out the intake? I'm pretty close to cutting my losses as I have another snowblower that starts first pull every time, but this one is lighter, quieter, wider cut, etc.
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Oct 10, 2020 23:05
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Doesn't run on starting fluid. When I say ran previously, it'd catch and then die almost immediately. Sometimes. Most of the time it wouldn't start at all. As for the carb, I took the bowl off to inspect, and found no ethanol gunk and what looked to be a very clean carb (which makes sense, as it was cleaned a year or two before I got it. Didn't disassemble given how clean it was, I was able to see that there was nothing blocking the nozzle. No apparent gunk or varnish, though I did find a teeny piece of grit stuck in the float assembly which was preventing it from closing properly, which I was able to dislodge, and the float seated properly afterwards. I sprayed it down with carb cleaner basically, not a whole lot beyond that given that everything looked good. I can see it drawing fuel out of the nozzle when the engine turns over trying to start, and feel that the puffs coming out the intake of the carb are wet for lack of a better word. Is there any situation where air should come out the intake of the carb?
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Oct 11, 2020 23:22
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Motronic posted:If it doesn't run on starting fluid but has spark it's time for a compression test. Yeah that's what I figured. It has spark (I put a new plug in already because why not), and while I had the plug out to check spark I stuck my finger in the spark plug hole (just enough to seal it off, definitely not into the cylinder) and turned it over slowly with the pull cord. It's definitely pulling vacuum, but I didn't feel much in the way of compression. It's a 12.5hp Tecumseh 4 stroke, guess I'll do a compression test and then probably start taking the head apart and see what I can learn. I have another functioning snowblower so it's not the end of the world if I can't get it running again. Speaking of, I changed the oil on my other snowblower and the damned thing started first pull. Why is it always the older, louder, heavier, more unpleasant to use things absolutely refuse to die?
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Oct 12, 2020 02:33
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Motronic posted:2stroke.txt? Nope it's an oldish 4stroke, grafted to a probably 40 year old frame/drive/auger assembly. Heavy as poo poo, have to disassemble a ridiculous amount of stuff to replace the belt, etc. A 2stroke would be lighter at least 
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Oct 12, 2020 03:00
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What *should* compression numbers show on a cold engine? I'm getting 65 PSI on the snowblower that won't start, and 60 PSI on the one that does. However, I've read that they hold one of the valves open during starting to make the pull cord easier, so I honestly don't know what to think. I'm going to try spraying some starting fluid in again. Edit: It caught on starting fluid and immediately died. I'm back to that loving carb, and given the size of the engine, there's no cheap solution - it's a $200CAD carb, with no rebuild kits available. Oh well, at least I've isolated the issue. Edit 2: When I removed the fuel shut off valve from the fuel line, it fires right up. Hopefully I've solved the float seating issue, but we'll see. I also managed to drop the gasket for the carb when I was pulling it apart, and it's vanished. Just completely MIA. I'll find a sheet of gasket material and cut one out, but it seems to be sealing alright without one (spraying carb cleaner around the carb -> engine connection doesn't have a noticeable change in engine speed. I'm still thinking something to do with the carb is hosed though. It'll idle fine with the choke on, but seems like it's running lean when the choke is turned off - it runs, and is constantly (every second or so) shooting fire out the exhaust with loud pops. Does this less when loaded. I'll keep loving with it. E3: I cleaned the jet out again, found a bit of crap at the top hole on the non-adjustable jet (per this pic, not mine but it looks identical)  Now it doesn't die with the choke off at least, instead it does this: https://i.imgur.com/tUWvgnW.mp4 Right click / show loop controls if you'd like to enable sound, otherwise imagine a bit of a pop and occasionally flame when the throttle is opened by the governor. Any ideas on why it would do this? TrueChaos fucked around with this message at 04:09 on Oct 15, 2020 |
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Oct 14, 2020 22:54
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Motronic posted:E: sorry, mised this earlier. That sounds like it's running out of fuel. I'd be checking the float bowl/float/float needle as well as making sure there is good fuel flow to the carb. Like......hoses, filter(s) shutoffs. No worries - I appreciate any suggestions, no matter when they come. So basically engine speed decreases (due to fuel starvation), the governor responds by increasing the throttle, it leans out & pops out the exhaust, normal fuel flow returns, repeat? I can confirm that the float moves freely with the bowl off, and I cleaned out the fuel needle spot with carb cleaner when I had it apart last. It doesn't have a fuel shutoff valve or a filter, and flow through the hoses seems fine (ask me about how much fuel I've spilled disconnecting and reconnecting the fuel line without a shutoff valve...). I can also push the little spring loaded fuel drain valve while it's running and there's fuel in the bowl. Does the bowl need to remain at a specific fuel level for it to run properly, or does it just need fuel in the bowl in general?
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Oct 23, 2020 02:27
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| # ¿ May 9, 2024 23:57 |
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Motronic posted:That is was what I thought I was hearing. Yeah, it makes sense. Happy to go through the carb again - I did the following: -Removed from engine (disconnecting the knob for the choke, the throttle linkage, the fuel line, and the primer bulb line) -Drained gas by pushing the drain valve on the bottom of the carb. Realized I didn't have enough towels for how much was in the bowl, spilled gas on the floor. -Removed bowl by unscrewing the non-adjustable jet on the bottom. -Inspected, noted that the assembly appeared clean (no gunk build up, nothing that looked weird). The snowblower has always been run with ethanol free gas. -Sprayed carb cleaner everywhere I could get it into. -Cleaned the tiny holes on the main jet bolt (poked a small piece of copper wire through. Nothing was dislodged, there was no issues getting the wire through, didn't feel like any buildup anywhere). Put it all back together. Realized that the reason it wouldn't run on starter fluid is I was spraying it through the carb directly against the closed throttle plate, then turning the throttle on and trying to start it. When I re-tested and realized what I'd done, it started on starting fluid. I'm going to mess around with it more tomorrow, want me to pull the carb apart and take pictures of everything? I've looked for a cheap replacement carb, but the ones of amazon that list compatibility with the tecumseh part number don't match dimensionally with the port sizes on the carb (i.e. where the carb mounts to the engine - the bolt spacing will be correct, but the carb opening itself is much smaller than the original one. The descriptions also seem to indicate a max of 5hp on the ones I've found, and this is a 12.5hp engine). Is it worth grabbing one that doesn't seem to match and seeing if it works any better? If I go for an OEM replacement it's like $200CAD, and the parts store guy didn't have any alternates in his system. He was surprised by that, as in his words 'usually I can get a cheap one for like 30$, but doesn't look like there's anything available for this one'.
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Oct 23, 2020 19:18
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