272 impulse hole... Am I dumb or?

[jordan henson]

So am I being really dumb? Because this 272 cylinder the impulse doesn't seem to go through?
I feel like the only reason that line would be there is if it actually went through right ??
I got this saw not running, I had it running but it would lean out, could this be why... I don't believe the p&c are OEM

 

[huskydave]

It should have a cross hole that goes down to the base of the cylinder to pick up the crankcase pulses close to the cylinder mounting hole, it almost touches the cylinder skirt. One of the holes may need to be drilled deeper or it could be plugged with something, make sure the base gasket isn't blocking that hole, it should have a small notch for it, that could be the issue. The intake gasket needs to be installed in the correct orientation also, don't ask me how I know..

 

[singinwoodwackr]

It should have a cross hole that goes down to the base of the cylinder to pick up the crankcase pulses close to the cylinder mounting hole, it almost touches the cylinder skirt. One of the holes may need to be drilled deeper or it could be plugged with something, make sure the base gasket isn't blocking that hole, that could be the issue. The intake gasket needs to be installed in the correct orientation also, don't ask me how I know..

Yea, they run funny when the block...and gasket are upside-down

 

[huskydave]

Yea, they run funny when the block...and gasket are upside-down

When I was 15. I had an old Rotax 335cc single ski-doo. It would start, run for 4 seconds and die. I fought with it after a carb rebuild for around 4 hours before I figured out the gasket was upside down. I started paying closer attention to the orientation of things after that disaster.

 

[singinwoodwackr]

When I was 15. I had an old Rotax 335cc single ski-doo. It would start, run for 4 seconds and die. I fought with it after a carb rebuild for around 4 hours before I figured out the gasket was upside down. I started paying closer attention to the orientation of things after that disaster.

Mine was a 288 I rebuilt. It ran and cut...for a short time. Hm..back to the shop, pulled the carb to rebuild, again, and noticed...oops...

 

[jordan henson]

I re did the whole carb and block and the gaskets, the whole time(took like hours doing it because I heard about it so much) being way too friggin cautious lol. The base gasket part was what I was missing I know for a fact it ain't notched, once again you fellas educate me with the lil bits of knowledge that help me on my journey of trying to do this full time!
Anytime I'm talking trees or saws with people there's a time in the conversation when they're just looking at me weird, then eventually go " see man like nobody woulda seen that, or why do you even know this", and I'm just ****in weird man.
Thanks y'all! I'm sure I'll have more 272 questions, eventually I'll move on to the next one or 372xpw, or 395.

 

[huskydave]

No problem, good luck.

 

[NSEric]

Is the intake block OEM?
I rebuilt one with an after market top end, intake block and carb.
The cylinder is the only good part in the kit, the intake block didnt line up and was too thin to seal, it would seal and run for 10 minutes than eat the gasket. The carb and gaskets were junk too.
That saw now has a aftermarket 272 cylinder with OEM 61 intake/carb with home made gaskets and it rips.

 

[Cantdog]

I re did the whole carb and block and the gaskets, the whole time(took like hours doing it because I heard about it so much) being way too friggin cautious lol. The base gasket part was what I was missing I know for a fact it ain't notched, once again you fellas educate me with the lil bits of knowledge that help me on my journey of trying to do this full time!
Anytime I'm talking trees or saws with people there's a time in the conversation when they're just looking at me weird, then eventually go " see man like nobody woulda seen that, or why do you even know this", and I'm just ****in weird man.
Thanks y'all! I'm sure I'll have more 272 questions, eventually I'll move on to the next one or 372xpw, or 395.

A few years ago I picked up a nice looking 266XP that a member had got really cheap from a guy because it would only run for 10 secs and quit. Ron was a fairly clever guy but had tried everything…. new ign, known good running carb, fuel line and filter, made sure the muffler wasn’t clogged and he couldn’t change problem. He was so mad he about gave it to me to get it out of his sight. I brought it back to the shop and started it right up with the same results….slept on it that night going over everything Ron had done…. Woke up with a hunch. Got to the shop and pulled the cyl complete with carb and muffler and sure enough there it was plain to see….the previous owner had flipped the cly base gasket end for end so the notches for the impulse were on the front side rather than the back. Since I had it apart I cleaned the piston up and put on a new ring, put the gasket on correctly. The thing started third pull and has been running great ever since!!