Mac 49 help

[steveohara]

Guys,

I was looking at a June 1968 Karting magazine tonight and found a McCulloch ad that shows the three models offered at that time. The ad shows a Mc 49, 91 and 101. The picture of the 49 shows an all yellow motor that looks just like a Mc 2. The image shows the motor from the recoil side and there is no label on the shroud in the position where the labels are located on the 49C and 49E.
Anyone have a picture of a Mc 49 sticker???
Steve O'Hara

[steveohara]

More on the early 49...
I found the IKF tech specs published in March 1969 and they show the specs for the 49C and a 49A. The A version is a two exhaust, four transfer port block with the shorter opening under the intake manifold and it also has the ribs running the length of the area under the manifold like the Mac 5 etc. The specs also show a different piston for the A model from the C model and it looks as though the rings are the thicker version although the scan is kind of fuzzy so I can't say for certain.
It's beginning to look like adding the 49 line to my collection is going to take up a lot more time and space than I first thought!
Steve O'Hara

[Scott Kneisel]

Yes Steve, that line seems quite complicated. Sounds like McCulloch was putting engines together for the rookie class from chainsaw parts. I purchased an Mc49 about 5 years ago from a guy who had it on a minibike and he claimed it was totally original without being touched. It was painted all yellow and looked to me like only the carb and intake manifold had ever been removed so he was probably right.
Now get this....
It had the 49C block like the picture I posted, had a thick ring piston and the big mystery was the crank....it had a straight 3/4" crank with a 3/16" keyway like the 49M/C. I suppose the crank could have been changed for the minibike app when it was new but it sure looked like it was never apart.

Just an FYI, the VERY early 250 saws had the block you are speaking of. I have one and it is stamped 250 but only has 2 exhaust ports drilled and 4 intake ports. I'll bet they used that block and I'll also bet it was a real dog!!

[Terry Bentley]

Steve, on that Mc49 block was the intake opening like either one of these?

Scott, the very early 250 saws 63/64 were leftover 200 models. They had all intake and exhaust drilled including third port induction. There were several variants of the 250 models that ran from 1963 thru 1970. The 250 pictured below has only four intakes, all three exhaust and no third port. Yours has the four intakes, two exhaust, but you didnt mention about the third port indution. The 4.9 cubic inch Mac motor was the most commoly produced model and used for a lot of things, including commercial applications. The straight shaft would fit the bill for that easily. During the mini-bike craze that followed the kart explosion, it would only make sense that Mcculloch would have offerings to that market also. Clinton, Power Products, and West Bend sure did.

Just about any of the early saws have two thick ring pistons, that are all interchangable. So mocking the Mc49 should be easy enough.

[Terry Bentley]

Anyone have a picture of a Mc 49 sticker???
Steve O'Hara

This pic is courtesy of McBobs awesome site.

[Terry Bentley]

The other one is a bit different... same shape fins, no numbers stamped on the back , exhaust port gasket surface recessed for the rectangular copper gasket, structural ribs running from base of intake manifold to the bottom of the block like the 91B blocks, threaded insert in the third screw location for the exhaust instead of tapped into the alloy. Shroud says 49C but it has the sloper manifold with the little Walbro carb like the 49E.

Your description fits my Mc49E exactly. It does not have the very rounded head fins like the Mc49M/C pictured on previous page.

[steveohara]

Terry,

The tech manual shows the 49(A) as having only one of the third port holes drilled so it is a two exhaust, four transfer and one down low across from the exhaust. The area under the intake is the same as the pics you posted. Intake and carb the same as the 49C.
I took another look at the sticker on the motor I have with the sloper and Walbro and the letter is nearly worn off and could be a "E" bit it sure looks more like it was a "C".
I have a NOS 49E coming to me so I will be able to compare and post info once it arrives.
Thanks again to all for sharing info.... with help and cooperation like this thread we can keep the McCulloch legacy alive well.
Regards,
Steve O'Hara

[mcbob]

Well when you get the story of the 49 worked out i'd be happy to add it to my site for all to see and read

McBob

[Terry Bentley]

Terry,
The tech manual shows the 49(A) as having only one of the third port holes drilled so it is a two exhaust, four transfer and one down low across from the exhaust. The area under the intake is the same as the pics you posted. Intake and carb the same as the 49C.

That one hole sould be about 1/4" diameter. It is on all saw motors that dont utilize the third port induction. I am guessing its just to vent the dead space, since the passage is blocked by the reed plate.

The two pics above are different on the intakes. One is just like the Mc5/6, the other is a later model with additional material below the early style gasket surface. Basically the same as pics on the Mc250 differences aa Scott posted on first page. The lower ribs can be milled out to open up large like the Mc7. If the Mc49 intake opening is exactly like the Mc5/6, the saw block of choice would be a 1-43. If it has the small opening with added material below, you have severeal options easily available from saws. The most common would be a Mc15. Another would be any particular Mc250 that happens to have the correct porting as the Mc49. But that would be a roll of the dice without tearing the motor down.

[steveohara]

The tech manual drawing shows the version with the extra material like your second picture.
I have a block that is just like it but the head is removable... I think it is an I-40 saw motor.
Thanks again for the info.
Steve