Recent content by rfarr94

Just picked up a Poulan 405 plus. Looks to have a scored piston and possibly cylinder. Anywhere to get a replacement piston and cylinder that’s any quality?

Probably a stupid question, but when you say from TDC is that the same as before top dead center? Don’t you time intake before top dead center or am I doing something wrong when timing?

67 btdc. I’ll re time it tonight. Trying to do everything a couple of times to make sure I’m not overlooking something stupid or obvious,

It has a schrader valve on the end of the threads a tube right up to the gauge that has pressure release on it.

I checked squish 3 times but can’t hurt to check again. When I timed the saw when I first put it together I got Exhaust 100 Transfers 116 Intake 67 That is with no base gasket. I don’t know enough about timing yet to know how much those numbers where they are would affect compression. I did...

Yeah I guess even if they make 100 good ones for every bad one you never know when your going to get the dud. And for 70 extra dollars I could have gotten oem and know I’m getting something but at least I’ll know for next time.

Yes the sealant has been cleaned up. I used an oem base gasket originally and had the same trouble starting.

That is definitely going to be my thinking going forward after this. I’ve contacted the company I bought it from so hopefully they can make it right but we’ll see.

Here’s the piston and cylinder. Looks like a little transfer where the skirt looks tight I guess but that’s all I see. No marks can be felt with a fingernail. Swapped to the other bottom end and same 120 compression. Decomps not leaking and cylinder didn’t look out of round at all when I shined...

Decomp has been plugged since I put it together. I’ve got another 61 maybe I’ll put the 272 top end on that and see if I have the same results.

Yeah I was hoping the low compression was the reason it didn’t want to start right. I guess once I figure out what’s causing that ill move onto the next problem.

Checked the ring end gap. I put the ring in the cylinder and used the piston so it was above the exhaust port and used feeler gauges to measure the gap. Came up with .015 had just a little resistance between the rings. Don’t know much about where it should be. Is that too loose or about right?

I was of the thinking that if you had an air leak the same volume would be sucked into the crankcase. It would just be sucked in from places other than the carb so you would have less fuel and oil in the mix and that’s why top ends burnt up with leaks but compression would remain the same...

I’ll have to check with the ring when I get home. I haven’t checked for air leaks but i didn’t see how they could affect compression being below the piston ring it should be sealed off from anything below the ring but I could be completely wrong.

Would you be able to maeasure if the cylinder is out of round with calipers or would you need something more accurate than that?