Mac 250 difference?

[2broke2ride]

Surprised nobody has mentioned it. The non super 250 is only 80cc. The 1-52 is 87cc if it is a 1-52, I question it because a 1-52 should have a full wrap handlebar and yours does not along with the yellow top cover.

 

[mogulmasher]

Well I got the 1-52 as a "parts" saw for the 250, I also thought it was a 1-40. I swapped the full wrap handle and also the can muffler over to the 250. As I stated before it has a yellow 1-40 cover but has 1-52 stamped underneath. I put it back together with the handle from the 250 and the stack muffler and fired it up. It runs great.

I didn't know it is 87cc saw and since it runs so good maybe I'll swap everything back over from the 250.

 

[mogulmasher]

Is there any difference in performance between the can and stack mufflers?

 

[2broke2ride]

Imo, no. Neither one is much of a "muffler" the stack may have a very slight advantage but i don't think you would ever be able to feel any difference.

 

[mogulmasher]

Well put the full wrap back on the 1-52 and a pick of model number underneath.

 

[carrbear]

Surprised nobody has mentioned it. The non super 250 is only 80cc. The 1-52 is 87cc if it is a 1-52, I question it because a 1-52 should have a full wrap handlebar and yours does not along with the yellow top cover.

Did you measure the bore and stroke on the 1-52 ? Acresinternet has this listed as a 80cc. The McCulloch 1-40,1-41,1-42,1-43,1-45,1-46,1-50,1-51,1-52,1-53,1-60,1-61,1-62,and1-63 were all 80cc according to acresinternet. The 87cc and larger engines started with the 1-70. Sometimes acresinternet has mistakes. Just wondering where you got the 87cc for the McCulloch 1-52.

http://www.acresinternet.com/cscc.n...4a5631ef0548581b88256b00006b7a44?OpenDocument

 

[mogulmasher]

2broke2ride stated that 1-52 is 87cc. I also searched and found other threads with guys that know their Macs stating the 1-52 and 1-53 are 87cc.

 

[carrbear]

I guess acresinternet needs a correction. Mark Heimannm, McCulloch expert with a huge McCulloch collection, has both the 1-52 and 1-53 at 87cc.

https://www.arboristsite.com/community/threads/big-old-mcculloch-questions.137494/

 

[RandyMac]

acresinternet is riddled with errors, several attempts to have things corrected have been ignored.

 

[2broke2ride]

Yup lots of wrong info on acres. It's a decent quick reference though.

 

[sawfun]

I cannot say anything about the regular 250 but the super 250 pulls a 36" bar and under better than a 550 or super 550. Those larger saws show their stuff above 36". The super 250 & 660 really rev higher compared to the 99cc and 103cc saws.

 

[mogulmasher]

Well I have little experience with any of these saws. I can just say pulling the same 20" bar and .404 chain this 1-52 noticeably outcuts the regular 250 when run back to back in the same wood. I can't believe just 7cc is that much difference?

 

[sawfun]

Some of these Mac saws have a strangely wonderful effect of behaving like they've been given a good shot of Nitrous.

During the PNW gtg, I had mentioned this behaviour to RandyMac who explained to me that it was likely that when loaded down heavily, the reeds open up further. It is very noticeable when the saw gains like 3000 +rpm instantly. An no, it's not a lean out as the saw pulls even harder. It makes me wonder about the reed material used and the porting along with it. Holy cow, things get real fast real quick with certain of these old yeller monsters.

So far this has happened with a super 250, 660, and 895. The 660 (36" bar buried) performed like a 650 until this effect, where it clearly showed it was a completely different animal when it came on. Like the saw grabbed another gear.

I have a NOT soft spoken 895 (2:1 gear) that just cut nice like an 1130g, then all of a sudden, it just started to scream and wanted more work. There was never even a small consideration of slowing down, none at all, perish the thought. That with a 60" bar buried in old Doug Fir. The harder I pulled on that saw, the more rpm it gained. I'd love to have had a tach, bet it was close to 13k rpm. There I had a very unhappy 6 cube saw thinking it had no load with a paltry 5 foot bar. I really think it would have been happier with another foot or two of bar.

 

[RandyMac]

it is kinda like popping the secondaries open on a four barrel carb.

 

[RandyMac]

I bucked Redwood with an 895, 72'' bar and 9/16th square bit, it would bury you to the knees in chips, in no time at all.

 

[Okie]

Is there any difference in performance between the can and stack mufflers?

The stack muffler has a really good sound and is built for the long haul, thick cast steel.

It's quite common for a old clutch side seal to not seal on these old dogs.

If you can get yourself a McCulloch SERVICE manual for these old saws, some very good service info about all.

I've got some of these old heavy Mac saws running good. I mainly use a lighter saw, but when I get a big tree down I get the old heavy Mac and just lay it on top of the log and let the weight of the saw get er dun.
Another good reason to have a stack muffler is for easy priming the saw when it's coming out of storage, just dump little mixed fuel into the stack muffler, (it's straight shot to the piston) tie the saws throttle wide open and go.

Mark Heinman gave me some good info to get me on track when I first started playing with the old Mac's. Also some good info over in the McC section of this site.

 

[mogulmasher]

Good points about the stack muffler, it does sound awesome and seems to more durable than the can muffler.

Never thought about priming thru muffler, good tip.

 

[Okie]

Good points about the stack muffler, it does sound awesome and seems to more durable than the can muffler.

Never thought about priming thru muffler, good tip.

I've got 4 or 5 of the old Mac's that are now good runners. I don't have a 250.
Mine are in the 1-46 to 1-53 areas.

I have a piece of #10 SOLID copper insulated electrical wire on the trigger handle on all the old Macs that I use to tie the throttle wide open when cranking and when get a start I just slide the wire off the trigger. Use a insulated wire stripped from a piece of Romes and the insulated wire won't damage the paint and slides easier, if the old Mac saw has any yeller paint still attached. One of mine was a very low hour saw, bar and chain OEM and looked almost new, but everything dried out from age, needed carb kit, fuel lines, gas tank cleaned, clutch side seal.
The stack muffler also really lets you adjust the carb for the 4 cycle sound also. I operate them at 32-1 to 40-1 and if mosquito's are bad I go little richer, but the new 50-1 oils are ok.

Have to keep a heads up on the manual oilers after using a auto oil saw, don't go asleep at the manual oiler in a long cut.

Them old heavy Mac's were not made for Nancy's and Pansies to operate.

They all start faster when the throttle is wide open, even when warmed up.

 

[mogulmasher]

Well I bragged a little too soon about the 1-52, it ran great that first time I bucked some wood with it. I just went out to try and finish up a small pile of wood still needing bucking and it won't run. It'll fire up ok, but won't take any throttle, just dies. It'll actually idle no problem, just won't rev.

My 2 stroke experience is in the snowmobile world and that would point to a carb problem. Crank seals or low compression make for hard starting. Once started crank seals usually make for a high and/or erratic idle and motor will still rev up. What do you guys think?

 

[Okie]

Probably starving for fuel.

Check the in tank fuel filter. Also take the air filter off and look in the air box and see if you see any raw gas, especially when it's idling. Yes or NO?

Also make sure that the stud that holds the air box cover on is snug into the top of the carb. If the little stud is loose (should be good snug) on the carb the fuel pump area of the carb will be weak and suck air.

Look carefully at the carb front, on top by the mounting bolts. usually one the left side and see if you see like maybe a HL-XX (two numbers and a letter) for example HL63D or HL87D.

Since it idles ok, this indicates that the seals are ok.
I would install a new spark plug although that is doubtful yours is bad, but a bad spark plug can really make a guy feel bad after he has checked everything else.

Let us know the carb type and we can put you onto a $15 free shipping kit, carb instructions if it's a HL type, etc.

Tillotson carbs are easy to work on if its' as Tillotson.

Just be cautious and keep a heads up when re-installing the carb, if the carb to intake adapters are not aligned and seated properly at the front, a ear can break off the intake manifold as the carb bolt is tightened and that is de-pressing.

Here is what Tillotson says about such
Engine will Not Accelerate.

1. Idle adjusting screw set too lean. Enrich idle adjustment

2. Incorrect setting on diaphragm lever. Reset (PROBABLY NOT THIS BECAUSE IT RAN GOOD BEFORE)

3. Diaphragm cover plate loose. Tighten this is on the bottom of the carb, carb has to be removed.

4. Diaphragm gasket leaking. Replace

5. Main fuel orifice plugged.

#1. Lean means that the front idle mixture jet screw is in CW little bit too far, enrich means back out (CCW) about 1/4 to 1/2 turn and see if it piss revs any better. in other words if the idle mixture screw is set CW for a real good idle the setting is too lean and the saw won't rev up, set the idle mixture richer CCW little bit and test.

If you back the front idle mixture screw out little bit and the engine idles is too low, and then rev's ok you will have to go to the idle speed screw and give it little bit more.

There is a very fine sintered iron filter at the gas input to the carb, if it's restricted the saw will starve for gas, but usually it will momentarly rev then starve. This filter is finer than the in tank filter and clogs easily if the tank is nasty.