I haven't updated this in ten forevers, but I've been messing with a project of sorts that might be worthy of more than 420 characters on Facebook. Who it might interest however is another story!
The thing I've been working on is an old weed eater. Might sound pretty boring, but it was designated as junk by the previous two people who had it, so rather than send it to the junk yard, I thought I'd try to make it run. And the objective is to do so without spending any money!
It's a Poulan GLT-800, which I can't really even find much about. The places who have anything regarding the GLT line seem to only recognize the 770 and 900. The 770 is pretty similar though from what I can tell. I have no idea when it was made, but it looks nothing like modern weed eaters. There's no plastic housing all over it. It's mostly just the motor, gas tank, and a pale green plastic shroud around the front to cover up the clutch, which also has the bolt to tighten down the shaft into it. You don't hold it by the shaft at all. There's an adjustable handle bar attached to the shaft which is half-way aligned with the shaft, and half-way pointed out 90-degrees. Both ends of that have rubber hand grips. The section aligned with the shaft is also where the throttle control and engine kill button are. I supposed this duel-grip handle which kind of surrounds your body more is supposed to give you better control, or easier on your back, I dunno. Since it has the fancy handle and the clutch, I've assumed it's more of an industrial weed eater. I'm more inclined to think that based on where it came from, too.
It wouldn't really do much of anything initially. I tried cleaning the carburetor out somewhat (it uses a fairly typical Walbro, but with no "primer" or return gas feed), but still not much of anything out of it. That's when my dad said we should just throw it out. But I had a few ideas to try on it. And if those wouldn't work, I'd just take it apart to see inside if nothing else. It'd be a learning experience.
One of the first things I found wrong was the spark plug. It was kinda sparking, but I noticed it was mostly happening down near the insulator and on the sidewall. Tried to clean it out some to see if that would help, but no good. So I swapped that out, saw this one sparking properly across the gap, and at that point it would sometimes sputter up better, but eventually go back to needing a million pulls with no result. I figured it was flooding out or something.
Later on I went for a much more thorough cleaning of the carb, which meant taking out the adjustment screws, the circuit plate, everything. The diaphragms aren't in great shape, but they're not terrible either. So I cleared out all the holes with carb cleaner, carefully scraped any crap off the edges to make sure everything had decent seals, tried to blow out the fuel screener, and put it back together. After mounting it back on, I decided I should check for spark first, just to make sure after all the other troubles so far. And there was none, coincidentally. Tried every spark plug laying around, and nothing. So all that carb cleaning was a waste of time at that point because now I had a new problem. I thought maybe the heavy rain had shorted out the coil or kill switch or something, and maybe it'd be fine the next day out in the sun.
Next chance I got I pulled the recoil off the back, which did have some water in it. But I immediately saw that the points (yes it's an old points and condenser setup) were gunked up. So after fighting for quite a while to get the flywheel off, I was able to clean it out, sand the contacts, adjust the gap, and start putting it back together. That's where things kinda went downhill for a bit, because I dropped a washer down inside the flywheel the first time and had to take it all the way back off. The second time, I realized I bent up the points plate with the screwdriver I'd wedged down in there to keep the flywheel from spinning while tightening the bolt. So off it came yet again. Managed to bend that back into shape, re-gapped it, and FINALLY put the ratchet levers and recoil back on it. Put the plug on, checked for spark, and it was good again. So that had been the problem apparently. I'd kind of been afraid that it might have been the coil, condenser/capacitor, or even the plug wire. So that was a step in the right direction.
Well after a few pulls to get it started, I realized it might be flooded again. I pulled the plug back out, noticed it was kind of wet, but like an idiot I decided to test for spark right then. And yes, I grounded it against the metal near the spark plug hole, like a pro. As soon as my brother yanked the cord for me, I got a fireball shot back in my direction. The cylinder had pushed all those fumes straight out the plug hole just as it sparked. I got up pretty quick! Only burned a couple of knuckles, luckily. Not on the hand holding the plug, though, ironically. Took the hair off of that hand some too. I put the ice on it so it didn't burn for too long, and only had one small blister. Totally a stupid place to ground the plug, where as I'd always been kinda careful about that beforehand. Oh well, lesson learned!
On the bright side, despite all the flywheel troubles and nearly burning my face off, I did make it run that day. It would even idle all on its own, albeit roughly. I was pretty proud to have accomplished that much, even if I got no further. But I was having to turn the mixture screws nearly all the way in, particularly the high screw, which meant it was likely getting way too much gas somewhere. So that'd be the next thing to focus on.
Next day I tried bending in the lever for the needle in the carb to lean it out a bit. I thought if less gas was sitting in the metering diaphragm then it might not flood out so much. The diaphragm is slightly stiffer than it should be too, which wasn't helping things. Well, problem was, I practically couldn't get it started then, despite my success the previous day. At one point when I'd put some more gas in it I did get it going better, and got up to some decent power (more than enough to engage the centrifugal clutch and actually hear that familiar whizzing sound of the head spinning fast). But during my screw adjustments it eventually died out, and I just never got it going well again. Wore a blister in the side of my finger in the process. Doesn't feel too great! I just couldn't figure out my intermittent success at getting it to start.
Later that night, I got to thinking. When I'd taken the gas cap off, it hissed, as if there were a vacuum. I put that together with the fact that the couple of times I'd gotten it to run great were after putting gas in it. That made me think that the gas cap was plugged up. Normally they're supposed to let air in but keep gas from going out. The vacuum was probably keeping it from getting enough fuel to stay running. And sitting out in the sun during the day was making that pressure worse, which was probably why I'd been having such a hard time getting it to do anything at the start of each day that I messed with it.
So today, when I got the chance, I went over and twisted the cap off, which released a bunch of vacuum again. Pulled the cord a few times, it sputtered up to speed, and despite not sounding perfect I still got quite a bit of power out of it, all things considered. I twisted the cap back down on it tight, and in a few seconds it sputtered out and died. So, that confirmed my problem, but didn't help me any either. It doesn't use a standard gas cap. So I'd either have to fix that valve in it or just jab a small hole in it.
Later in the afternoon I went back out to try adjusting the screws while running it with a loose gas cap. But I couldn't get it to start. Back to this shit again, it seemed. I decided to bend that lever back in the carb to make it a bit more rich again while I was at it. I also took the recoil off to see if I could figure out what was causing it to catch hard occasionally. Oiled it up and stuff, put it back together, then pulled on it a few times. That's when I noticed that the cord was frayed bad at the very end up inside there, and was starting to hang up. Insert another sigh, and commence ripping the recoil back off, removing the wheel and rope. Looked like it had been messed up in there for a while, since there was a piece of rope really crammed down in the channel on the wheel. So I chopped it off, re-knotted it, rewound it, fiddled with it for a while before I could redo the tension on the spring properly, but finally finished that. Though it still didn't want to work perfectly every time after I started trying to start the thing, since now the cord sometimes hangs out about half an inch or so after some pulls. I dunno what's up with it.
Eventually I did get it to start (which seemed a little easier now), and started tweaking the screws. Got some decent power out of it again at one point. But by accident I noticed air coming out of the carb opening. A lot of air. And sprinkles of gas. Yet another problem! So, turned it off again, and started trying to diagnose that. Took the exhaust off, but the exhaust port looked really clean. Cleared out the muffler as best I could with a screwdriver, stuck it back on, but no difference. So I put it away for today. This is obviously why I can't get it to run smoothly all the time. It sounds like it misses a spark sometimes, especially when it starts to get real choppy, which is usually the result of this kind of back-pressure messing up the carb.
So the potential issues now are: bad fuel pump gasket/diaphragm, bad intake port gaskets (it uses a stupid carb adapter so there's two gaskets, and yes they're really worn gaskets), or a bad reed valve/cylinder in backwards/who knows. I don't know what type of induction this engine uses so I can't determine the latter potential problem at this point. I don't even know if a two-stroke piston port induction engine would run at all with the cylinder in backwards. But based on the intake/exhaust arrangement, I'm more inclined to think it uses reed valves. If they're broken/missing/whatever, then I'm basically fucked, since I didn't want to put money into it.
What I'm going to do is loosen the carb, then slip a piece of cardboard between the carb and the carb adapter to block off the impulse jet. Then I'll pull the cord over and few times real fast and see if I feel any air coming back through the carb opening. If so, then it's probably a problem in the engine itself (unless the air is seeping through the gaskets and into the carb throat). If I don't feel anything though, then it's probably the fuel pump gasket/diaphragm leaking the impulse pressure out through the carb. That's also a problem since I didn't want to spend money, unless I can find a good one on one of the spare carbs laying around.
There's a couple of other issues too. Sometimes when I pull the cord it feels like there's no compression. Then immediately afterward it'll feel like there is again. So I don't know if that could be bad rings or a bad cylinder or crank gasket or what. Also, after repairing the recoil today, I suddenly started to notice that the cord had oil on it. I'm almost positive that it didn't when I as fixing it. That might mean the rear oil seal on the crankshaft is blown. Mighta happened from all that beating on it the other day to knock the flywheel loose. I don't think that would be why I'd loose all compression though, since I should still be feeling it from the cylinder. But, when I cleaned out the points before, it seemed a little greasy in there too, so it may have already been doing that to some degree. If so, it might lose spark again if it gets too gunked up.
One thing I'm tempted to try is cereal box gaskets. I've heard they work in various circumstances. I might put'em on the intake, and maybe even on the head and crank if I pull the entire engine apart. Might even fix the compression issue!
Anyway, this is a huge post, but I was catching up on many days worth of work. Any follow-ups I do won't be nearly as long.