Be warry of carb kit intake gasket

[JoeMay]

The intake manifolds on many older saws include provision for routing crankcase impulse to the carb. See pic of intake manifold from an Olympyk 480 Super. The gasket that comes with genuine and non genuine Tillotson carb rebuild kits does not maintain the integrity of the routing for the crankcase impulse. See second pic of manifold with kit gasket. I went round and round trying to remedy an old saw not starting when warm unless choked, surging at idle, even accelerating from idle with no throttle applied and failing to accelerate when triggered to. All low-speed circuit issues. The fix was easy and absolute with a hand made gasket using bulk material from an auto parts store.

 

[firefighterwolf]

Yup. I don't know why Tillotson even puts those gaskets in their kits. They almost are never usable... for the reason you illustrated above.

 

[Bobby Kirbos]

Yup. I don't know why Tillotson even puts those gaskets in their kits. They almost are never usable... for the reason you illustrated above.

Because "1 size fits all" sometimes means "1 size fits most".

 

[Cantdog]

Yep same thing on the older Jonsereds.....I've cautioned people on this feature many times. Not sure it will work on the Oyimpyc but the carb gasket for a Husky 61, 266,268, 272 etc will work fine on the older Jonsereds. I expect it would as well on your saw as the Tilly carb and impulse hole is in the same place. I'd say roughly half of my Jonsereds carbs have home made gaskets the rest Husky gaskets. I even scan and print up 8 1/2 X 11" sheets of gaskets on 1/32" gasket material in my printer to cut my own by.

 

[JoeMay]

The saw I was actually having problems with was a Jonsered 49SP. I had the Oly intake manifold at hand because I'm just about done rehabbing two 261's and a 480 Super. The Jonsered and Oly intake manifolds are indeed very similar. Luckily the OEM gaskets on the Oly's were in good shape.

 

[Cantdog]

The saw I was actually having problems with was a Jonsered 49SP. I had the Oly intake manifold at hand because I'm just about done rehabbing two 261's and a 480 Super. The Jonsered and Oly intake manifolds are indeed very similar. Luckily the OEM gaskets on the Oly's were in good shape.

LOL!! I am somewhat familiar with the 49SP!! Actually the template I made to print gaskets is made up of nine 49sp/52/52E cyl base gaskets with a carb gasket in the center of each to make better use of the whole sheet of gasket material. But like I said if you have a Husky dealer handy you can get an off the shelf replacement for a buck or two. The OEM Jonsereds gaskets have been NLA for many, many years.

 

[JoeMay]

Husky dealer is 10 minute drive away. Faster than cutting out shapes and punching holes. Thanks for the input.

BTW, a good-quality, adjustable leather-punch tool really works slick to make the mounting bolt holes and the impulse hole in the gasket material.

 

[Cantdog]

Husky dealer is 10 minute drive away. Faster than cutting out shapes and punching holes. Thanks for the input.

BTW, a good-quality, adjustable leather-punch tool really works slick to make the mounting bolt holes and the impulse hole in the gasket material.

Definitely!! Only way to go!! Another tip is to punch all the holes first......then cut out the inside and lastly cut the outside. Doing it in this order virtually eliminates accidentally ripping a thin gasket when cutting the harder to cut interior shape or when punching holes in a thin area of the gasket that's already been cut to shape.

 

[JoeMay]

Yup, learned about that order of punch first and cut second the hard way. Luckily there was relatively little at stake when that happened.
I really like that 49SP. I put an ignition chip in it to improve reliability and longevity; cheap and easy to do.

 

[HarleyT]

Yup. I don't know why Tillotson even puts those gaskets in their kits. They almost are never usable... for the reason you illustrated above.

They just want to see if the rebuilder is awake.....

 

[trappermike]

That gasket in the kit sabotaged uncountable carb rebuilds. It does fit a 1929 Skil or old Partner...

 

[JoeMay]

Count mine in among the uncountable. Ran the saw today bucking maple and ash. Ran and cut perfectly. I'm running an 8 pin / .325 / 16 inch setup on the business end.

 

[trappermike]

Maybe that gasket compells people to buy a new carb and is still making Tillotson money...? They still include it in kits 35 years after I first saw them,but they still don't know it's useless?

 

[JoeMay]

It's either devious or stupid, or maybe both on their (Tillotson's) part.

 

[Bobby Kirbos]

It's either devious or stupid, or maybe both on their (Tillotson's) part.

(Please forgive my ignorance if this is not the case)
It is possible that:

• The OP's carb is an older design and
• The rebuild kit works for all of their stuff made post {some date} and
• the engineers at Tillotson assume that anything needing the "special" gasket has been discarded many years ago therefore
• There is no need to include the "special" gasket for the 1 in 1000 who need it?

Unless they are still using the same design on current production OR they know that many are still being used, good luck finding the head gasket for a 1972 Ford {whatever} from the factory. It will either be after market or make it yourself.

 

[HarleyT]

A carb mounting gasket is usually a part that is supplied by the saw manufacturer, not the carb maker.
So don't be mad at Tillotson, you probably bought an aftermarket kit anyway.

 

[JoeMay]

The kit I bought was Tilli's (original) RK-23-HS. I am more frustrated with myself than mad at Tilli. I like their carbs; goes back to my snowmobiling roots. You are correct with the gasket really being the saw manufacturer's responsibility; trouble is, for older saws they are not readily available. I did manage to find and purchase a Jonsered one for another project. A lesson learned the hard way.

 

[keychange]

Hi nearest Husky dealer is 300 kms away. I see references to a template ( I have 49SP ) but I can't find any links to the template.

 

[Chainsaw Jim]

All you need to do is punch the two holes for the carb mount studs so you can line up the intake with the gasket material to trace the center bore. I like to pin the gasket material to the intake block with two 5mm screws and cut the center hole out with an exacto-knife.
It doesn't matter what the outer shape is as long as the overall footprint covers the entire impulse canal/passage. Don't cut the impulse hole too close to the inside bore... it's easy to do.

 

[keychange]

ok but where does the impulse hole go