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Well-Known Member
- Messages
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Hi
After some time not touching my octane lemon, as it still wouldn't run properly even though I thought I had finally found the problem in a mismatched carb, I had another go the other day as I had an idea I wanted to try out, kind of "fault tracing" idea.
Me, and a lots of others, have the problem that the car runs for a short while, then stops. When restarted, it'll run for a second or two, and stop. If it starts at all.
If you wait a while, it will run a short while, and then again same thing.
So, I figured, it's some kind of heat issue.
Also, one thing I have noticed is that when I heat the engine up with a hair dryer or a heat gun. I only need to heat the egnine up a very short time, before the sleeve gets so loose I can easily pick it up with my fingers, it's completely loose in the cylinder.
So, here's what i did.
Measured compression, 10 pulls = 150 psi
Started the engine.
Let it run for maybe 20 seconds or so until it stopped. Then same thing as always, starts and stops within 1-2 seconds.
Now I heated the engine with a heat gun, to get it quite hot.
Tried to start it, and now, even hotter, it will not start at all, not even for a second or two.
So heating it up, makes it not work. Not really a surprise.
So, with engine hot, I tested compression, 10 pulls = 100 psi.
Hence, I loose a lot of compression just like that, when the engine gets hot.
Now I am thinking this loss of compression is related to the cylinder sleeve coming loose when the engine gets hot.
However, I can't really see how the combustion chamber compression (to be precise) should drop due to a loose sleeve. But clearly it does.
What I am thinking though, is that the crankcase compression gets ruined.
If the cylinder sleeve isn't snug tight to the cylinder, I am thinking you can have the gas sneak out in between the sleeve and the cylinder, loosing crankcase compression. If this happens, you won't get any gas into the combustion chamber, and the engine dies.
Any thoughts on this?
Also, any thoughts on why the combustion chamber compression drops when the engine is hot?
After some time not touching my octane lemon, as it still wouldn't run properly even though I thought I had finally found the problem in a mismatched carb, I had another go the other day as I had an idea I wanted to try out, kind of "fault tracing" idea.
Me, and a lots of others, have the problem that the car runs for a short while, then stops. When restarted, it'll run for a second or two, and stop. If it starts at all.
If you wait a while, it will run a short while, and then again same thing.
So, I figured, it's some kind of heat issue.
Also, one thing I have noticed is that when I heat the engine up with a hair dryer or a heat gun. I only need to heat the egnine up a very short time, before the sleeve gets so loose I can easily pick it up with my fingers, it's completely loose in the cylinder.
So, here's what i did.
Measured compression, 10 pulls = 150 psi
Started the engine.
Let it run for maybe 20 seconds or so until it stopped. Then same thing as always, starts and stops within 1-2 seconds.
Now I heated the engine with a heat gun, to get it quite hot.
Tried to start it, and now, even hotter, it will not start at all, not even for a second or two.
So heating it up, makes it not work. Not really a surprise.
So, with engine hot, I tested compression, 10 pulls = 100 psi.
Hence, I loose a lot of compression just like that, when the engine gets hot.
Now I am thinking this loss of compression is related to the cylinder sleeve coming loose when the engine gets hot.
However, I can't really see how the combustion chamber compression (to be precise) should drop due to a loose sleeve. But clearly it does.
What I am thinking though, is that the crankcase compression gets ruined.
If the cylinder sleeve isn't snug tight to the cylinder, I am thinking you can have the gas sneak out in between the sleeve and the cylinder, loosing crankcase compression. If this happens, you won't get any gas into the combustion chamber, and the engine dies.
Any thoughts on this?
Also, any thoughts on why the combustion chamber compression drops when the engine is hot?