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pacodiablo

2 Stroke Troubles

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pacodiablo
As some know I have an old McCulloch 2 stroke engine. It is a miracle the magneto even pulls (this engine sat for 10 years - nobody even pulled the chord), but I got it running...sort of. I originally used silicone to seal the carb, but the gas ate away at it because I used the wrong kind (it was just laying around). After that I ordered a rebuild kit. I installed the kit, but lost one screw that holds part of the carb together. I found a similar screw that had a different head and thread pattern. I filled the tank with 20:1 and pulled the chord. Nothing happened. I repeated until it did, and it ran good, but it would die within seconds of being cranked. Could the incorrect screw cause this? I think it is a possibility...maybe it did not hold tight enough allowing gas to leak through the gasket? I used starting fluid, which helped a little. Could the gas have been bad? The gas has sat for some time, but no more than 5 or 6 months. The magneto pulls fine, I have had the throttle and choke on. What could be the culprit of this engine's failure?

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PatRarick
On a two stroke, the fuel mixture is drawn into the crankcase from the suction of the upward motion of the piston. The downward motion of the piston pressurizes the crankcase, which sends the fuel mixture into the cylinder through a port. On an engine sitting that long, it could be that the crankshaft seals have dried out, allowing it to suck air from around those seals. Another thing could be stuck rings, so the proper crankcase suction or cylinder compression cannot be developed. Pat

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pacodiablo
Thanks.

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a7117puller
old McCulloch 2 stroke engine, ....thats the problem

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Good_Ole_JR
Most 2 strokes that I have worked on have a reed plate behind the carb that allows the flow of air/fuel mixture to only flow one way. If the reeds are not operating properly that could be the culprit.

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rokon2813
I've found most of the 2 stroke weed eater type engines arent worth the hassle. I buy Weedeater brand trimmers for about $60, use them till they quit (usually 4 or 5 years) then throw them out and buy new. For $10 to $15 a year there not worth wasting your precious time on. There is little enough time to go around as it is. Just my opinion

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pofarm
Years ago, a McCulloch dealer told my dad that McCulloch made a real good engine, but the carbs were junk. He advised my dad not to buy one because of this. I figure that if a dealer made this claim, and my dad wasn't looking for a chainsaw at the time, it was probably good advise.

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pacodiablo
The carb is a little Zama. I think I figured out the problem. The valve did not go in right (I seem to have a problem with that, don't I?). I am going to buy the correct screw today...no point in doing the job the wrong way.

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pacodiablo
quote:
Originally posted by rokon2813
I've found most of the 2 stroke weed eater type engines arent worth the hassle. I buy Weedeater brand trimmers for about $60, use them till they quit (usually 4 or 5 years) then throw them out and buy new. For $10 to $15 a year there not worth wasting your precious time on. There is little enough time to go around as it is. Just my opinion
It is cheaper for me to rebuild what I have. Plus, I don't like to throw away an engine unless it is in such bad shape that it can't run correctly again.

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pacodiablo
I am keeping my fingers crossed...I sealed up everything and cleaned the fuel filter and repaired and area where the fuel line comes out of the tank that had a slow leak. I am going to let the gasket compound sit until tomorrow night then gas & fire her up. Hopefully it will not die as soon as it starts. I thought about doing a ring job, but that would be too much $$$ to put into this engine and one of the bolts holding the block in place is frozen, and I have tried everything short of drilling it out to get it to move.

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