Hi everyone, first of all, thanks for taking the time to read this. I hope someone out there can help.
I have a 4 cycle trimmer, Troybilt TB6044XL. It won't start and has low compression (20 psi). When I add oil into the spark plug hole I get a whopping 40 psi. It has spark, it has air, it has fuel.
I have read that there is likely something wrong with my piston rings, because adding the oil has doubled the psi, but I still only get 40. So I've opened-up the engine and examined the piston and rings. They don't seem obviously damaged, rusted, or warped, but I don't really know what I'm looking for other than that. There are some friction marks on the inside of the cylinder, but it feels smooth to the touch.
I'll admit that all my compression tests were done after I opened the thing up then put it back together with the original gasket, but it's an all rubber gasket and the thing was already not running.
The background on the thing is:
It's a year old with probably a good 30 minutes of use on it. I left normal gas from the gas station in it over winter (I have replaced the carb), and a few weeks ago I whipped it out and used it for about 3 minutes before it died. I was able to start it again, after which it smoked for about a minute then died for good. I definitely overfilled the oil tank because it has no fill line.
Anyway, I think I can install a new piston or new rings, but to the novice eye the rings look fine. But can anyone tell me:
1) Did I maybe screw up the cylinder?
2) Can I conclude that it is either the cylinder or the piston rings that are the problem, because of the oil-in-the-spark-plug test?
3) And has anyone ever heard of 40 psi being acceptable in a 4 cycle engine?
Thanks for reading and I hope we can figure this out together.
I have a 4 cycle trimmer, Troybilt TB6044XL. It won't start and has low compression (20 psi). When I add oil into the spark plug hole I get a whopping 40 psi. It has spark, it has air, it has fuel.
I have read that there is likely something wrong with my piston rings, because adding the oil has doubled the psi, but I still only get 40. So I've opened-up the engine and examined the piston and rings. They don't seem obviously damaged, rusted, or warped, but I don't really know what I'm looking for other than that. There are some friction marks on the inside of the cylinder, but it feels smooth to the touch.
I'll admit that all my compression tests were done after I opened the thing up then put it back together with the original gasket, but it's an all rubber gasket and the thing was already not running.
The background on the thing is:
It's a year old with probably a good 30 minutes of use on it. I left normal gas from the gas station in it over winter (I have replaced the carb), and a few weeks ago I whipped it out and used it for about 3 minutes before it died. I was able to start it again, after which it smoked for about a minute then died for good. I definitely overfilled the oil tank because it has no fill line.
Anyway, I think I can install a new piston or new rings, but to the novice eye the rings look fine. But can anyone tell me:
1) Did I maybe screw up the cylinder?
2) Can I conclude that it is either the cylinder or the piston rings that are the problem, because of the oil-in-the-spark-plug test?
3) And has anyone ever heard of 40 psi being acceptable in a 4 cycle engine?
Thanks for reading and I hope we can figure this out together.
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