Can some Husqvarna person explain why the cylinder gasket blocks the impulse port?

[Modifiedmark]

So here's the deal, I work on a lot of saws, just never been inside this series of Husqvarna much.

I found why this 266SE won't run, the OEM gasket blocks the impulse hole in the cylinder. The saw came to me apart, but I used the same exact number cylinder for a replacement and a new piston. The cylinder gasket that came off the saw is identical to the brand new 501512204 cylinder gasket from Husky.

I only gave it a passing glance when putting it together. Only when the saw wouldn't run, only start on choke for a bit that I really started to look closer.

Long story short I took it back apart and had to clip the corner of the gasket to uncover the impulse hole in the cylinder. What is going on? How is the gasket suppose work covering the impulse hole. The OEM gasket pictures that I see online are all the same, no impulse hole.

I will show some pictures to explain better.

If you look close you can see the triangle intent in the gasket where it blocks of the hole



You can see the impulse hole in the cylinder



So I snipped the gasket to clear the impulse hole.



Showing the modified gasket on the cylinder.



Matches the notch in the case



Why is the gasket not notched from the factory?

How did the saw run before I got it with that gasket? ( the saw was a basket case when I got it)

I wish I would have paid attention to the one in my Jred 630 when I put a piston in it last year or two.

 

[cscltd]

Isn’t your position of gasket wrong.
rounded end goes toward chain brake- can see outline in crankcase?
the premade notch on gasket will line up with impulse hole in cylinder

 

[Modifiedmark]

Thank you! I went and looked, at the old cylinder and gasket, your right, it needed turned 90 deg.

The round end of the original gasket was indented for the front of the cylinder.

The way it came to me was wrong and I couldn't see the forest for the trees. My dumb ass move. Some days are like that!

 

[cscltd]

No worries, I think all have had one of those moments in repairing saws.
maybe more than once in my case-lol

 

[Bob Hedgecutter]

Just jump up and down, swear a bit and then tear someone a new one for sending you a Jonsered 625 gasket for a 2## Husqvarna!

Easiest way around it is to throw all base gaskets aside and use a liquid gasket maker- although it can be done to block an impulse with that stuff as well.

 

[old guy]

I just put a 372 together that ran like massive air leak, so I set it up for test, it made no pressure or vacuum, pulled the cyl. off and there it was, somehow I had managed to tear off almost 1/4 off the base gasket.

 

[link]

If you can modify it, then whats the problem?

 

[Cantdog]

roncoinc had a 266 that would not run......he had it apart 5-6 times....different igns...different carbs....he fought and fought with it...never won.. I was down to his an great..place and he was so mad at it he said if I could get it running I could have it. Same exact problem.....the PO had turned the cyl base gasket a quarter turn. I put it back together and it started second pull and ran great!! He had not pulled the cyl so didn't catch it. I said I didn't need it but he put it in the back of my truck and said "Good riddance"...so it now lives one state over!!!

 

[Modifiedmark]

No worries, I think all have had one of those moments in repairing saws.
maybe more than once in my case-lol

Anyone who works on a lot of saws defiantly will have that moment now and again.

Just bugs me that I could see something wrong and it didn't connect. I'll blame it on a "senior" moment. Haha

 

[Modifiedmark]

roncoinc had a 266 that would not run......he had it apart 5-6 times....different igns...different carbs....he fought and fought with it...never won.. I was down to his an great..place and he was so mad at it he said if I could get it running I could have it. Same exact problem.....the PO had turned the cyl base gasket a quarter turn. I put it back together and it started second pull and ran great!! He had not pulled the cyl so didn't catch it. I said I didn't need it but he put it in the back of my truck and said "Good riddance"...so it now lives one state over!!!

roncoinc , thats a name I have not heard in some time. Good guy who I hope is doing well.

Believe me, for a moment I was thinking of using this saw for target practice.

It runs good now, I think I will keep this one around for my own use.

Might move the 630 down the road, no need to keep two of these same physical size saws and might as well keep the bigger displacement one.

I did find a NOS coil for it as well.

 

[Tomos770]

"NOS" stands for....?

Tnx in advance

 

[Bob Hedgecutter]

"NOS" stands for....?

Tnx in advance

NOS= New Old Stock.

 

[pioneerguy600]

roncoinc , thats a name I have not heard in some time. Good guy who I hope is doing well.

Believe me, for a moment I was thinking of using this saw for target practice.

It runs good now, I think I will keep this one around for my own use.

Might move the 630 down the road, no need to keep two of these same physical size saws and might as well keep the bigger displacement one.

I did find a NOS coil for it as well.

Ron is doing ok, I read posts from him most days.

 

[jakethesnake]

I had a similar issue with a 272. It has impulse hold in the hard plastic intake block. I’m not certain of the origin of my gaskets but they didn’t have the hole for the impulse. I punched it out with something small and round and finally got the thing running.

The gaskets came with the saw in a box of parts. Had everything to make it run with a couple extra rubber mounts and smalls. Reminds me I need to go over that oiler on that one. I have 3 of those. One of my all time favorite saws