McCulloch Chain Saws

[vinnywv]

K-10 sdc. Is the kit for the sp81 walbro carbs

 

[Maintenance supervisor]

That's right @edju1958 I was rescued here. But then what happened was I put the carb on, pulled once and the saw started immediately. It was stuck on high revs, so I screwed the idle screw out. I must have screwed too much because after 25 seconds the saw stalled.

I went in raising my arms in victory to my wife, who just looked puzzled. Anyway, declared victory too early. I was not able to start the saw again yesterday.

Basically it floods the engine now. When pulling from time to time I can hear hissing out of the top of the carb, and it will give one explosion here and there, but not start.

It may be a faulty impulse line (got a Stihl one on order), but that doesn't chime with the compression that I feel is there, and the vacuum is also ok.

I may have made some mistake with the carb rebuild. I want to take a look at the metering lever, maybe that little metal seesaw pulls the needle too much which can cause the flooding....i am not sure but imagine this could be the case. I do not have a gauge so not sure what the right height is. Anyway, i'll keep at it and the lesson continues I guess.

The needle lever or seesaw needs to be level with the casting of the carb body. Where the diaphragm hooks to it.

 

[PogoInTheWoods]

Where the diaphragm hooks to it.

Key point right there if it is a forked metering lever (on both ends). The slotted button in the bottom center of the diaphragm must be properly positioned in the fork of the metering lever, not resting on top of it like an un-slotted type. The diaphragm must also be positioned on top of the gasket (between the gasket and cover) when assembled.

 

[Yokosukadweller]

Key point right there if it is a forked metering lever (on both ends). The slotted button in the bottom center of the diaphragm must be properly positioned in the fork of the metering lever, not resting on top of it like an un-slotted type. The diaphragm must also be positioned on top of the gasket (between the gasket and cover) when assembled.

I think I get it now. That button narrows in the middle which allows it to slide into the rear fork of the metering lever, is it? I am almost 100% sure that I positioned that button on top of the center round intention of the metering lever (the one that holds the spring in place on the other side) and not at the end. Time to reopen and try again.

 

[heimannm]

Check out the illustrations in the attached document, I think they will help.

To further explain, most metering levers on the SDC carburetors will have a fork on each end, the short end engages the metering needle, the longer end engages the metering diaphragm. The "indentation" provides a positive position for the metering spring.









Mark

 

[PogoInTheWoods]

MacAttack may also benefit from that PDF over in the MM thread.

 

[Maintenance supervisor]

They must have made 27" Echo bars for McCulloch saws, because no echo sold around here pulls it like the SP81.
Thanks to Woodslasher I was able to step the very worn groove up to .058 guage chain.

 

[edju1958]

Ozzie,what make & model carb do you have on your SP81?I can't remember what model was on mine,but I know it was like yours & I had it changed out to an SDC37.I want to say you have an SDC51,so if that's true you'll need the K10-SDC

 

[edju1958]

Today was another "maintenance" day.I had to put a couple parts in the DE80.First was the grommet on the rear handle brace.I put that on & then went to put the plastic piece that fits under the handle & it just wouldn't fit.I know the screw is supposed to hold it in place,but it seems that the insert is about 1/8 in.too long.I figured I'd start the beast up since it hasn't been run in about 2 months.Next thing I knew the rope was hanging all the way out & didn't want to retract.Just as well because I had to pull the spring out to put in the plastic recoil shield.Sure enough the spring had pulled out of the slot.That's what I get for being cheap & not putting in the the new spring I bought back 2 months ago.So I had to pull the recoil off the saw,pull it apart,& put the new parts in.I put the recoil back on the saw & it worked great,but the saw wouldn't start.I ended up giving it a prime & it fired right up.Smoked like hell,but it ran good.I hope I can find some bigger wood this fall to sink it into.

 

[Yokosukadweller]

Another update: went back to the SDC carb today. I don't know what was wrong but I decided to use all parts from the carb set even tho the old gaskets and needle and lever looked alright. After replacing all that and reassembly she started up immediately. Smoking like a mofo tho. But anyway the saw starts consistently and runs now and I'm really pleased. It's very satisfying when I compare to the state it was when I bought it for cheap.
One thing I discovered was this carb goes directly against the tank bottom - only a carb gasket between. My 2-10 which I'm also working on has the same carb but it also has a fat carb spacer. I guess these are random or is it missing on the cp/sp 70?

 

[vinnywv]

Its a diffetent set up and thete is just a gasket on the sp70 saw. No spacer

 

[ozziechainsaw]

K-10 sdc. Is the kit for the sp81 walbro carbs

Thanks for that.

 

[heimannm]

The rigid mount saws like the 2-10 need the additional insulator to minimize the heat that gets transferred to the carburetor. There is one insulator between the cylinder and the airbox, and another between the airbox and the carburetor.

The anti-vibe type saws have just one insulator between the cylinder and the boot, the boot itself and the airspace between the cylinder and airbox provide adequate insulation to minimize the heat transferred to the carburetor.

Mark

 

[PogoInTheWoods]

Ran across this vid this morning from Mac 131 regarding servicing the duckbills on the more stubborn Mac fuel caps that used the molded aluminum inserts for the vents. Definitely worth a look and a thumbs up. He's evidently restricting access and you'll need to use the 'Watch on YouTube' link to watch.

​

 

[knightmax]

Had a chance to start on the 850 with the US chrome reworked block. Will finish her up soon...

 

[PogoInTheWoods]

You missed a spot. LOL

But seriously, I hope there isn't excessive sealant on the inside of the case that could loosen up and smear all over that nice new cylinder. I've seen it more than once, even from the factory on a PM8200 I rescued a few years back. Made a real mess.

And I imagine everyone is tired of hearing it by now, but I always preach making sure the case is tight with a vac/pressure test while at that easy stage for doing one. Could save taking things back apart just to chase a leak that could have been dealt with before boltin' all those other parts together.

Looks to be coming along nicely otherwise.

 

[emf123]

Had a chance to start on the 850 with the US chrome reworked block. Will finish her up soon...

Did you just get your 850 block within the last couple weeks? I had an 800 up there that I just got back and I know the guy who deals with US chrome sent another one in with mine (for Bob J). They're apparently swamped with work, won't even answer the phone unless you're a dealer. Anyways, did you remove the impulse nipple before you sent it up to them? I did not, and when I got it back I was wondering if I should have because it looks like they blast the block or wash it an acid because all the sealant was off it. How and what did you use to get it out?

Thanks,
Eric

 

[knightmax]

T

Did you just get your 850 block within the last couple weeks? I had an 800 up there that I just got back and I know the guy who deals with US chrome sent another one in with mine (for Bob J). They're apparently swamped with work, won't even answer the phone unless you're a dealer. Anyways, did you remove the impulse nipple before you sent it up to them? I did not, and when I got it back I was wondering if I should have because it looks like they blast the block or wash it an acid because all the sealant was off it. How and what did you use to get it out?

Thanks,
Eric

I sent them to Bob with the nipples in... came back without them. I got a few from Bob. the one there is brand new set with red loctite

 

[knightmax]

You missed a spot. LOL

But seriously, I hope there isn't excessive sealant on the inside of the case that could loosen up and smear all over that nice new cylinder. I've seen it more than once, even from the factory on a PM8200 I rescued a few years back. Made a real mess.

And I imagine everyone is tired of hearing it by now, but I always preach making sure the case is tight with a vac/pressure test while at that easy stage for doing one. Could save taking things back apart just to chase a leak that could have been dealt with before boltin' all those other parts together.

Looks to be coming along nicely otherwise.

Theres plenty there but not excess. I am lucky I had my uncle supervising hes built dozens of these 82cc saw. He said cover all the faces, then stop to much is as bad as not enough lol. so I stopped. I just got a mighty vac kit to replace my cheap our broken down homemade tester for carbs. But uncle assured me there was plenty of gasket sealant and there would be no leaks. So this time we do it his way. its been years since I had one all the way down. and he built those back block wise. not to digress but his health is very bad. My Dad and him ran these saws sine I can remember. I wanted/want to learn from him all i can before his knowledge is lost. he has 50 plus old macs. and a **** ton of salvaged parts for the 10 series 82cc saws. I have about 9 and some parts myself. every time I fire one it takes me back to the mid 80's. So there you have it. I run these because they take me back to a place of joy and fond memories. I realize there are several here that know more than I do. I however am a disciple of the 82 cc 10 series still learning each day. I appreciate the knowledge and information here.

 

[matt_lamb_160]

I am looking at front tank saw (Super 250 etc) seals again. Sticking to dual ball bearing saws I have:

FW crank seals ball bearing: SKF 6763 (17.5mm shaft/30.18 OD); Timken: 474261 (17.5mm shaft/30.15mm OD)
Would a Timken: 17X30X6-R2LS32-S be better (for a 17mm shaft instead of a 17.5mm)? It is a bit deep to measure with by calipers, but I get the bore to be 30.05 to 30.1 mm.
Another option is an oil pump seal for a TOYOTA VISTA CV30 1990-1994 (16.9x30.25x6.9)

PTO crank seals ball bearing: SKF 6640
Timken be another option: 17X35X7-R2LS32-S

This tool is helpful: https://www.timken.com/engineering-tools/seal-selection-tool/