McCulloch Chain Saws

[brandonstc6]

Is this the correct carburetor kit for a Mcculloch 795 with a Tillotson HL carburetor?

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[heimannm]

That is gaskets and diaphragms only, but yes the parts are correct for the HL.

The full kit with the metering needle and seat ++ is RK88HL

Mark

 

[brandonstc6]

That is gaskets and diaphragms only, but yes the parts are correct for the HL.

The full kit with the metering needle and seat ++ is RK88HL

Mark

Thanks


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[BigBlue]

Randy's Engine Repair, also a popular e-bay seller.

http://stores.ebay.com/Randys-Engine-Repair/Store-Policies.html

Mark

Neither of those guys has one. Thanks for the suggestion though. I'll keep my active search going on eBay and see what happens.

I'm still interested in people's opinions of whether the Lil' Red Barn piston is a decent substitute or crap. I'm OK with 'good enough' in this case because it isn't going to get huge use. But I don't want to install something that will just make a bigger mess.

Rob

 

[Rio95]

https://store.chainsawr.com/collect...c-850-2-06-chainsaw-piston-assembly-92518-new

Also an aftermarket, but I have found pistons from Chainsawr to be good quality. They may have a good used one - they do pop up time to time. I have bought a lot from Chainsawr, and have had no complaints

 

[BigBlue]

https://store.chainsawr.com/collect...c-850-2-06-chainsaw-piston-assembly-92518-new

Also an aftermarket, but I have found pistons from Chainsawr to be good quality. They may have a good used one - they do pop up time to time. I have bought a lot from Chainsawr, and have had no complaints

Thanks. That's a 92518 but I need a 92519 for my PM800 though and it doesn't look like they have that in stock. Looks like this one might fit my SP81, so I'll keep it in mind for that.

Rob

 

[fossil]

Neither of those guys has one. Thanks for the suggestion though. I'll keep my active search going on eBay and see what happens.

I'm still interested in people's opinions of whether the Lil' Red Barn piston is a decent substitute or crap. I'm OK with 'good enough' in this case because it isn't going to get huge use. But I don't want to install something that will just make a bigger mess.

Rob

I've seem some comparisons to OEM pistons and the height of the piston crown to the wrist pin was different leading to low comp or a smash up. One guy ordered a Poulan 3400 piston which has a press fit wrist pin with no keepers. The one he received had keepers and a slide in pin. The piston also needs to be chrome plated which it wasn't. It ran for a bout two minutes.

I've never handled one myself and I can't say they are all bad but they are definitely a buyer beware venture and bear proper measuring and inspection before using.

 

[brandonstc6]

Where can I find a new fuel line for my Mcculloch 795? What has everyone else done for a fuel line
Thanks


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[heimannm]

Check with Bob Johnson (607 638 9297) or Randy Duncan for the fuel line. Another option is select a fuel line that fits over the barb on the carburetor, then see if you can find a grommet that fits the hole in the tank and slip the fuel line through it.

I received a package today, perhaps you recall seeing this one a few pages back.



I cleaned it up a bit behind the clutch, added the sawdust screen and an H&S spike.







A little bit of tuning was required, but is starts and runs quite nicely. I probably won't get a chance to put it in any wood until next year.

Mark

 

[Brian Thacker]

I got a piston from Little Red Barn. I wound up not using it and opted for the thin ring OEM piston, but I would have used it if I did not find a OEM piston. It looked alright. I did not check the wrist pin to dome clearance but I can tomorrow and see if it differs from a OEM piston. If that is all you can find then I would use it.

Mark
Nice looking 250.

Brian

 

[BigBlue]

I got a piston from Little Red Barn. I wound up not using it and opted for the thin ring OEM piston, but I would have used it if I did not find a OEM piston. It looked alright. I did not check the wrist pin to dome clearance but I can tomorrow and see if it differs from a OEM piston. If that is all you can find then I would use it.

Mark
Nice looking 250.

Brian

Thanks for the info. I'd appreciate knowing what you find when you measure things. Also, is there a web site or something that could tell me what I need to measure & verify on a new piston to make sure it is correct for my engine? I assumed that ordering something with the correct part number would automatically be enough 'verification', but I guess maybe not?

Rob

 

[heimannm]

If you have a known cylinder ("A", "B", or "C") then with the correct part number piston (92518/A, 92519/B, 92520/C) no further measurement would be required.

If you purchase an aftermarket piston it wouldn't hurt to check, but I think you would need to measure the bore as well as the piston at the same time to compare. If you take one measurement of the piston at 70º F then hold it long enough to warm it up to 85ºF and take a second measurement, the diameter will have increased around 0.00036" which will throw you off in your comparison with the chart below. In the same way, you can't measure the cylinder when it is 50ºF and the piston when it is 70ºF and make a determination, they would need to be more or less the same temperature and measured at the same time with the same instruments to make an accurate assessment.

Mark

 

[Colton T]

Off topic but I am wondering if there is any other part # associated with SDC-20 carbs . . . I want to replace the HSH 124 on my 125 and have read from previous posts that an SDC-20 is a good replacement carb I cannot find one for the life of me! Are they listed differently or does it represent a broad generalization for SDC series carbs?

Anyone got one they want to sell?

Thank you!

 

[OldDeadWood]

Hay Mark

I haven't been around for awhile, so I thought I'd drop in and see who was here.
I'm glad to see that you're still going strong.
I like your end table.

ODW

 

[Brian Thacker]

Rob, It being Christmas I am in the giving mood. If you will PM me your address I will give/send you a Christmas present of one LRB piston. When you get it you can take the ring off the piston and put it in the bore of the cylinder and check the ring end gap. If it is better than .006 I am unsure of what the upper limit is, maybe Mark can furnish this. But if the ring is in these parameters then the piston should be alright. Not the best way to do it but I have done it in the past and gotten by with it. Or measure the piston and bore and see if they are correct and also the you can put the piston on the crank, slide it into the cylinder and check the squish. If it will work for you then Merry Christmas.

Colton, I built a 101B kart saw and used a SDC-20 carb on it and it worked great. I have actually been looking for a SDC-20 for my SP125C also. They will work and the SDC has both low adjust as well as high. The tillison as you know has a fixed main (high) jet. I would also like to be able to adjust my high speed settings. Keep a look out on ebay, I let one slip threw my fingers but always keep an eye out for one there.

Brian

 

[Colton T]

Rob, It being Christmas I am in the giving mood. If you will PM me your address I will give/send you a Christmas present of one LRB piston. When you get it you can take the ring off the piston and put it in the bore of the cylinder and check the ring end gap. If it is better than .006 I am unsure of what the upper limit is, maybe Mark can furnish this. But if the ring is in these parameters then the piston should be alright. Not the best way to do it but I have done it in the past and gotten by with it. Or measure the piston and bore and see if they are correct and also the you can put the piston on the crank, slide it into the cylinder and check the squish. If it will work for you then Merry Christmas.

Colton, I built a 101B kart saw and used a SDC-20 carb on it and it worked great. I have actually been looking for a SDC-20 for my SP125C also. They will work and the SDC has both low adjust as well as high. The tillison as you know has a fixed main (high) jet. I would also like to be able to adjust my high speed settings. Keep a look out on ebay, I let one slip threw my fingers but always keep an eye out for one there.

Brian

Thanks!

Are they listed as SDC-20’s. Is that part number stamped in the body of the carb?


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[ML12]

Also an aftermarket, but I have found pistons from Chainsawr to be good quality.

I bought one for a SP81 I was rebuilding, but the piston was machined poorly, wouldn't clear the counter weights on the crank and the ring grooves weren't actually deep enough for the ring to sit in all the way, so the piston wouldn't even go in the bore. I assume I just got a bad one out of the lot, and I polished up the old piston with emery cloth and put it back in. The saw makes huge compression still so its fine.

 

[heimannm]

I think you will find the SDC20 is a rare bird, used on the CP125 and highly desirable due to the adjustable high speed jet. You should have an easier time locating an SDC37, but there were no particular part numbers marked on the carburetors, only the Walbro stamp indicating what the carburetor is. Keep in mind these were highly interchangeable and McCulloch was never bound to follow any system as to what carbuetor they put on the different models. The only way to know for sure what you are getting is to find the Walbro number on the body of the carburetor. While the overall dimensions on all the SDC carburetors is the same, the layout and orientation of the idle speed and L and H jets was variable so you may have to look at a few to determine which is the best fit. Also keep in mind that the CP125 and SP125 impulse signal came through a separate line to the fuel pump cover, the 10 Series all received the impulse signal through the mounting flange so if you find a suitable donor off a 10 Series you will have to find a fuel pump cover with the impulse fitting or add one yourself.

I put an SDC18 off a CP70 on one of my SP125's, in addition to adding the impulse fitting, I had to grind a little clearance for the H screw head and adjusting the H and L is quite challenging due to their location. The idle speed is no longer adjustable except for tweaking the throttle rod and I have to remove the AF cover to turn the choke on or off. I am sure I could make up a different choke rod but this particular saw is just a GTG cookie cutter so it doesn't matter to me. In my opinion the performance gain was well worth it since the original carburetor was the smaller version.

This is a 37A, I am not sure if the 3-76 is a manufacture date or something else.



McCulloch Carburetor Usage – SDC & Zama C2 Carburetors

Carburetor Venturi Throttle Idle Hi Used On

SDC 2 .625 .750 Ext Adj 1-10, 2-10A, 2-10PS, 2-10G, S2-10, 3-10E, 5-10E, 5-10G, 6-10, LG 6A, S LG2, S60-10A,S10-10, S10-10A

SDC3 .625 .750 Int Adj 10-10, 10-10A, 10-10E

SDC4 .625 .750 Int Adj 10-10

SDC7 .625 .750 Int Adj Mac 15 (no Fuel Pump)

SDC16 .625 .750 Ext Adj S10-10, S10-10A, S10-10E

SDC18 .750 .812 Ext Adj CP55, CP70, CP70L, 7-10A, S2-10A, S6-10A

SDC19 . .750 .812 Int Adj 795L, S797

SDC20 .750 .812 Int Adj CP125

SDC22 .750 .812 Ext Adj S2-10, 7-10A

SDC37 .750 .812 Int Adj 10-10, 10-10A

SDC38 . .750 .812 Ext Adj SP80

SDC38A .750 .812 Ext Adj SP55, 60, 70, 80, 81, 81E, PM570, PM850

SDC43 .750 .812 Int Fixed MC49E

SDC44 . .750 .812 Ext Adj 7-10A, PM60

SDC49 .750 .812 Int Fixed PM55, PM60, PM555, PM700, PM700, PM10-10S

SDC50 . .750 .812 Int Fixed SP60

SDC51 .750 .812 Ext Fixed SP81

SDC65 .750 .812 Int Adj PM10-10, Pro 10-10A

Zama C2 .750 .812 Ext Adj PM850, 800, 805

Mark

 

[heimannm]

Original



Replaced



Mark

 

[happysaws]

Original

View attachment 619651

Replaced

View attachment 619652

Mark

Did you snatch up those NOS SDC20's off eBay a few weeks ago? There were 4 available for under $50 a piece.