McCulloch Chain Saws

[donthraen]

Hmm... he might be hiding something then... likely a smaller engine, if possible... :msp_sneaky:

I saw that and tried to ask things but didn't get answers aether so I gave up on it I felt he is hiding something

 

[Ambull]

Hmm... he might be hiding something then... likely a smaller engine, if possible... :msp_sneaky:

I recently picked up a ebay saw from a seller that would not disclose much info. I played around with it today, and it is a 740, I think....

Anyways, the thing has good compression, and runs great on a prime, but I can't get the carb to do anything. I went through Heimann's carb post, and I took it all apart, and this thing is kicking my a$$.

Carb has the original stapled gaskets on the fuel pump layer. On the metering layer, I can't for the life of me figure out how that pump works, as it doesn't connect to either the pin or the diaphragm. The diaphragm looks a little on the loose side, but everything else seems in order.

Any advice would be appreciated.

 

[promac850]

I saw that and tried to ask things but didn't get answers aether so I gave up on it I felt he is hiding something

I would suspect that's what he is doing then... how much is he asking for it? the right price for the saw (55, 1-80, etc.) or a price that would be good for something even smaller than that?

 

[Mr. Bow Saw]

you know the rules.....


pic's or it didnt happen :msp_w00t:

Ok...I can't find any pics but here's one of my crew.:hmm3grin2orange:

I did have to fix the signs they are holding though..:msp_biggrin::msp_unsure::msp_w00t:

 

[RandyMac]

Cliff, I think that pic made your little motor run faster.

 

[a. palmer jr.]

Ok...I can't find any pics but here's one of my crew.:hmm3grin2orange:

I did have to fix the signs they are holding though..:msp_biggrin::msp_unsure::msp_w00t:

You wouldn't want to see my crew. 65+

 

[heimannm]

watsonr - 1-80 or Super 55, air filter cover and front handle mount say it is not a 55. Most Super A's (44 or 55) have the hockey mask grill covering the air intake on the flywheel cover.

Ambull - the metering diaphragm doesn't hook up like the SDC and other carburetors, just the metal tip of the plate on the diaphragm contacting the lever arm.

I even have a kit at home with no metal plate, just a dab of glue or sealer in the middle of the metering diaphragm to bare against the metering lever.

Most will have at least a metal plate attached to contact the metering lever, this is the Sugar Creek Supply kit

Others will have a little metal tit on the metal plate that contacts the metering lever

Just make sure there is a gasket between the body of the carburetor and the metering diaphragm, give it a little more room to flex and work the lever

Mark

 

[Eccentric]

Thick rings = 0.062" or there abouts, the ones I just checked with my dial indicator seemed to be 0.063+

Thin rings - 0.025".

While I was up there looking I found two sets of 48691, thin rings for the 2.125" bore saws like the 1-81, 1-45, 1-72, 1-75 and several of the kart engines.

Mark

Thanks for the info Mark. That's exactly what we were needing.

Just ran out to the shop and checked the 1-76 rings with the micrometer, looks like about .025 with crappy light and no glasses - Sam

Sam that means you need the thin 48978 rings instead of the thick 58881 rings.

Those numbers are for standard bore. For thin 99cc Mac rings, the PN is 48934 for .010 over, 59587 for .020 over, and 59586 for .030 over.

Sam - If you have a spare set of 1-76 rings for sale we need to talk. I have a relatively nice 1-76 with about 130 PSI compression that could use a little freshening up.

Mark

I saw some of the 48978 rings on a Kart site Mark.

You guys don't need to spend big bucks on rings. You can get rings made on the cheap at Otto Engine Works- Home

Thanks Jacob! I'll be contacting those fellers for rings for my Homelite 900D, AH58 powered Wards/Mono WD60, and McCulloch Super 250.

 

[Ambull]

Thanks Heimann. If I don't get anywhere with this saw, I'm sending it to you.

 

[little possum]

Cliff, do you need some summer help?

 

[promac850]

Others will have a little metal tit on the metal plate that contacts the metering lever

Mark

I've never thought to call or heard of someone calling that little bump a 'tit' Am I the only one that almost laughed after reading that? Sorry...


but look at these tits!!!

Okay, back on topic... anyone have a 790 fuel tank laying around?

 

[dieselsmoke]

promac, Quit staring at Marks tits....

 

[struggle]

Today I was going to try and start the sp125 but it filled back up with oil evidently:mad2:

Can I remove the oil pump with out taking the fuel tank off? It looks like it is tucked under the fuel tank a bit. Or is it better to remove the whole tank assembly? Not sure if Bob in NY will have the gaskets and such or will I be able to reuse the the tank gasket.

Also what and where are the numbers to verify this thing is a true SP125 on the block? I bought it on the assumption that it is a SP125 but is it possible to be a standard one? That would be a bummer, but I must find out for sure. It has the air filter cover that looks rather original to it but that don't mean much. The muffler is kind of hollowed out style? Was there different mufflers on these as well between the sp and standard 125?

 

[Rounder]

Thanks for the info Mark. That's exactly what we were needing.



Sam that means you need the thin 48978 rings instead of the thick 58881 rings.

Those numbers are for standard bore. For thin 99cc Mac rings, the PN is 48934 for .010 over, 59587 for .020 over, and 59586 for .030 over.



I saw some of the 48978 rings on a Kart site Mark.



Thanks Jacob! I'll be contacting those fellers for rings for my Homelite 900D, AH58 powered Wards/Mono WD60, and McCulloch Super 250.

Thanks Aaron and JJ, very helpful, decided to sell a few saws to finance the 1-76 and 895....they are well worth being brought back to their former glory. Can't wait to finish them and take them up to the job and kill a couple trees with them. As they were intended to do. - Sam

 

[Eccentric]

Today I was going to try and start the sp125 but it filled back up with oil evidently:mad2:

Can I remove the oil pump with out taking the fuel tank off? It looks like it is tucked under the fuel tank a bit. Or is it better to remove the whole tank assembly? Not sure if Bob in NY will have the gaskets and such or will I be able to reuse the the tank gasket.

Also what and where are the numbers to verify this thing is a true SP125 on the block? I bought it on the assumption that it is a SP125 but is it possible to be a standard one? That would be a bummer, but I must find out for sure. It has the air filter cover that looks rather original to it but that don't mean much. The muffler is kind of hollowed out style? Was there different mufflers on these as well between the sp and standard 125?

To my knowledge, there were no "standard" 125's. They were either CP125's or SP125's. Do you have the model/serial # tag? The Acres listings have the model numbers listed for these saws.

Acres' listing for the CP125 and CP125S:

Model Profile: CP 125

Model Profile: CP 125S

Acres' listings for the SP125 and SP125C:

Model Profile: Super Pro 125

Model Profile: Super Pro125C

Tomorrow afternoon I'll look in my IPL's for the block #'s of the CP and SP saws. Off to hit the rack now. Gotta get up at 0400...

 

[dieselsmoke]

Thanks Aaron and JJ, very helpful, decided to sell a few saws to finance the 1-76 and 895....they are well worth being brought back to their former glory. Can't wait to finish them and take them up to the job and kill a couple trees with them. As they were intended to do. - Sam

Now that's the right attitude. But when it happens, we need pics.

 

[Rounder]

Now that's the right attitude. But when it happens, we need pics.

There will be pics, I'm very thankful to work for people who get as much of a kick as I do out of falling a tree with my vintage saws. 'Tis what they were meant for after all. Just might take me a while to get all the bits and pieces together.......well worth it though - Sam

 

[heimannm]

Struggle - Best way to confirm SP125 is to measure the bore and stroke, you can do this by removing the muffler to measure the bore through the exhaust port, and remove the spark plug to measure the stroke.

If it has the "pop up" type compression release it is most likely an SP125, could possibly be an SP105 but there were not quite as many of them.

You need to post some photo's of the muffler, both of my SP125's as well as the SP105's have a sort of removable, cylindrical baffle in the muffler. Original mufflers were box type affairs but there were round ones that would fit as well, just not OEM on those saws.

Mark

 

[cpr]

In addition to the button vs. DSP decomp will be the exhaust port itself. The SP will have no bridge, the CP and 797 will have 1 in the middle. Also, stick a small magnet in the the exhaust port to the far wall of the cyl. If it sticks, it is and early SP/CP/797 and can be bored. If it doesn't, it is a late model chrome lined, thus the SP-125"c" and can't be bored.

 

[watsonr]

Mac heads....test of the day

got a points saw that won't fire. Heres the story;

points have been gaped at .020 and nicely polished. I verified with a continuity tester that the points break right at the timing mark on the flywheel, lower limb of the coil. On/Off switch is working correctly. Plug wire was remade with a new wire, firmly seated in the coil and plug boot. Plug gapped at .025 and nice bright metal at the electrode. The opening where the points wire goes thru the body of the saw is not touching the case to ground it out. My spark tester shows good spark thru the glass window when I pull the starter.

It has a new fuel filter and fuel line, impulse hose checked for cracks. The carb is clean and diaphragm is supple and installed correctly. It does put fuel thru the muffler after a bunch of pulls, not flooding just some spray on the muffler that evaporates very fast. I also tried squirting some fuel thru the carb throat just to make sure she was getting fuel.

It will not run, it has 145lbs compression, tried both compression release on and off. Unhooked the on/off switch.

Question; the points wire attached the the left side and on/off switch is attached to the right side of the coil or are they both attached to the same side? The IPL does not show this and I don't have the shop manual, but I do believe I've got it right, coil on the left, on/off on the right. My thumb is on the left side of the coil in this picture. I've swapped the condenser for another to eliminate that potential and the wiring from the coil to the points just to make sure. Air gap set at a business card, measured it at .011, no rust on the magnet or laminated pick-up arm.

What say you?