Ch-ch-ch-- no engine movement when trying to start

[jrmints]

That's called compression, a requirement for the engine to run.

Okay, so that's a good thing (?)

Once it hits that point, the engine struggles to keep the fan turning and sometimes it can't.

[Bear45-70]

That's called compression, a requirement for the engine to run.

Okay, so that's a good thing (?)

Without it the engine can not run. To make an engine run you need 3 things;

1) Compression, in these engines case about 80 to 90 PSI to run and 115 PSI to meet the manufacturer's spec.

2) Fuel, a a sufficient fuel to air ratio to have combustion, 14 to 1 is ideal.

3) Spark, enough spark to ignite the mixture at the right time.

FYI Jr Mints have always been one of my favorite candies.

[jrmints]

That's called compression, a requirement for the engine to run.

Okay, so that's a good thing (?)

Without it the engine can not run. To make an engine run you need 3 things;

1) Compression, in these engines case about 80 to 90 PSI to run and 115 PSI to meet the manufacturer's spec.

2) Fuel, a a sufficient fuel to air ratio to have combustion, 14 to 1 is ideal.

3) Spark, enough spark to ignite the mixture at the right time.

FYI Jr Mints have always been one of my favorite candies.

Always been my favorite screen name

Checking those three things now.

e: I'm reading Fred's Guide, and I don't think I'm getting enough compression. I did the whole thumb-plugging-spark-hole thing and while it did give off some pressure, it wasn't nearly enough to pop my thumb off.

[Bear45-70]

Okay, so that's a good thing (?)

Without it the engine can not run. To make an engine run you need 3 things;

1) Compression, in these engines case about 80 to 90 PSI to run and 115 PSI to meet the manufacturer's spec.

2) Fuel, a a sufficient fuel to air ratio to have combustion, 14 to 1 is ideal.

3) Spark, enough spark to ignite the mixture at the right time.

FYI Jr Mints have always been one of my favorite candies.

Always been my favorite screen name

Checking those three things now.

e: I'm reading Fred's Guide, and I don't think I'm getting enough compression. I did the whole thumb-plugging-spark-hole thing and while it did give off some pressure, it wasn't nearly enough to pop my thumb off.

The thumb method tells you nothing. Get a compression gauge and really check compression properly. * 40 PSI will pop your finger off the plug hole, but the engine will NEVER run with 40 PSI compression.

Harbor Freight has gauges on the cheap.

http://www.harborfreight.com/flex-drive ... 92697.html

[jrmints]

Okay, you guys are going to hate me (moreso if you already do), but I decided to take the cylinder head off to check the piston. The top is covered in carbon. I'm cleaning it now. Does any kind of oil/lubricant belong on it when I put it back together with the metal accordion thing that the muffler attaches to?

[Bear45-70]

Okay, you guys are going to hate me (moreso if you already do), but I decided to take the cylinder head off to check the piston. The top is covered in carbon. I'm cleaning it now. Does any kind of oil/lubricant belong on it when I put it back together with the metal accordion thing that the muffler attaches to?

Cleaning the piston top and the head will LOWER your compression. It is hurting nothing at this point and cleaning is a waste of time. Put a very small amount of 2 stroke oil in the cylinder before you reinstall the head, maybe a 1/4 of a teaspoon. You are aware you need a new head gasket now, are you not?

[jrmints]

Okay, you guys are going to hate me (moreso if you already do), but I decided to take the cylinder head off to check the piston. The top is covered in carbon. I'm cleaning it now. Does any kind of oil/lubricant belong on it when I put it back together with the metal accordion thing that the muffler attaches to?

Cleaning the piston top and the head will LOWER your compression. It is hurting nothing at this point and cleaning is a waste of time. Put a very small amount of 2 stroke oil in the cylinder before you reinstall the head, maybe a 1/4 of a teaspoon. You are aware you need a new head gasket now, are you not?

Aware now. I think I read that low compression can be caused by blown gaskets, so it probably wouldn't hurt, n'est-ce pas?


e: is the gasket supposed to be fused to the engine?

[eliteguy50]

New development: I've noticed that when I try to spin the fan manually, or kickstart, there's a spot where it starts being hard to spin. Once you push past that spot, it'll spin fine until you hit it again.

Compression build up is good as Bear said, as long as it is smooth when you turn it.

[jrmints]

More fun discovery, those two rings around the piston are both broken.

[eliteguy50]

More fun discovery, those two rings around the piston are both broken.

The e-start sounded fast to me.

Yes, the cylinder base gasket can be a pain to remove. It is best to clean the dirt off of the block before removing the head. That way everything is enclosed so you wont get dirt it the bottom end. Broken rings could mean a new bottom end if the pieces found their way into the crank bearings.

[jrmints]

....am I crazy for wanting to put a big bore kit on it now?

I mean, maybe it'll be usable in the city if a 48mm can haul a 160-lb chick around...

dammit, this forum is getting to my head!

[Bear45-70]

....am I crazy for wanting to put a big bore kit on it now?

No, It will be as cheap as replacing with OEM parts.

[Wheelman-111]

Greetings:

Rings are "broken"? Sorry if this sounds elementary, but rings have a split to permit installation and expansion.

I would expect a broken ring to fall off the piston in at least 2 chumks upon withdrawal from the cylinder.

[eliteguy50]

Greetings:

Rings are "broken"? Sorry if this sounds elementary, but rings have a split to permit installation and expansion.

I would expect a broken ring to fall off the piston in at least 2 chumks upon withdrawal from the cylinder.

I was wondering about that but I can't open the attached picture. Is there a secret method that I am not using?

[jrmints]

Greetings:

Rings are "broken"? Sorry if this sounds elementary, but rings have a split to permit installation and expansion.

I would expect a broken ring to fall off the piston in at least 2 chumks upon withdrawal from the cylinder.

No, no, I mean split into several pieces. I fished all of them out, though. They were stuck onto the piston with some kind of... goo.