Sears "mantis" tiller won't start

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Old 04-13-06, 12:21 AM
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Sears "mantis" tiller won't start

I read thread #5533 by stumped 1 and have all the same descriptions of the problem. It's a Tecumseh engine 32.8cc and I have spark & fuel flow, the next part of the equation is compression. I checked and on one or two cycles the gauge read 30psi if I turn the engine over rapidly it goes up to 60 psi. I haven't been able to find the spec online and I suspect this is too low, right? Hence the no start problem. By the by I bought this thing at an auction and have no idea about previous history. Kodibear
 
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Old 04-13-06, 02:54 AM
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If you are, in fact, spinning the engine over with the rewind starter thus getting a good full pull, then 60 is on the low side and would warrant removing the muffler to inspect the piston, ring(s) and cylinder. The piston and cylinder should be nice and shiney and the ring(s) should "float" in the groove. Now removing the muffler won't let you look at the exhaust port side of the cylinder so you need to do this by looking through the spark plug hole. Bear in mind that this is not the best way to view such but it is the easiest. This will give you an idea of any possible trouble. To be absolutely certain, you would need to remove the jug (cylinder) from the crankcase. One other thing, if the piston and cylinder are scored and depending on the severity, you may also have trouble (damage) to the crank and bearings. In other words, it may not be a low cost repair.
 
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Old 04-14-06, 05:45 PM
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I had the muffler off already and the portion of the piston that is visible has some minor lines scored on it. Nothing that looked really serious. I did not attempt to move the rings though and see if they are free moving. I had looked in the plug hole and didn't see anything that alarmed me like huge caking of carbon or shiny slivers etc. I will remove the jug and advise what I find.
Is there reed valves in a 2stroke like in a compressor? For the intake and exhaust. I have never torn down a 2 stroke. Thanx for the advice so far. Kodi
 
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Old 04-15-06, 06:05 AM
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Small two-stroke engines are piston port - in other words, no reed valves. Before tearing the engine apart to check the rings, simply take a small blade flat screwdriver and press the ring(s) through the exhaust port and check to see if they move in the landing. It will only be minimal but this will save you the time and needed gaskets if you do a tear down.
 
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Old 04-16-06, 07:33 AM
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puey61 I thought all 2 cycle engines had reed valves like weedtrimmers,blowers

Jerry
 
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Old 04-17-06, 12:37 AM
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Most small 2-strokes like you'd see on a blower or trimmer do not have reed valves. Most larger ones do, but these are usually found on lawnmowers, dirt tampers, boat motors, etc...
 
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Old 04-17-06, 04:45 AM
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How the OEM designs their equipment also is a factor in how they meter the fuel into the engine. If the carburetor is mounted to the crankcase (as opposed to the cylinder) then there will be reed valves. Many Weed Eater brand units are this style as well as some smaller Homelite saws and I know there are others but they just don't come to mind right now.
 
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