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Dirtcrasher
01-16-2003, 05:26 PM
My throw away saw, a McCulloch won't start when it's warm. It runs well and then I set it down and thats it, yank pull yank. Today I almost threw it in the fire. I thought I finally had it. This had started all of a sudden so I thought maybe there was gunk in the carb. It doesn't have a bowl so it must have a one way valve or diaphragm. So I tore it all down cleaned everything and put in a carb rebuild kit. But it does the same thing!!! I looked in the exhaust port and the piston and wall look good, not all beat like the old saw I had. Could it just be rings??? Also the L and H adjustment screw, Are they fuel screw for low and high RPM's?? How other than sound do I adjust them?? In for less fuel and out for more - or what??? Thank you! :?

01-16-2003, 06:37 PM
Hey,
I have alot of these motors....some came off saws, others were made specifically for racing.....it appears to me that the McCulloch Carburetors will eventually stop working.....no reason...they will just stop! we use tillotson carbs on our motors....but for the Mcculloch carbs initial adjustment is as follows: Open Idle fuel needle 1 1/4 turns out, and main fuel needle 1 1/2 turns out, then when engine is warm, adjust from there....Do you know what kind it is?? McCulloch i know, but like a Mc-2, is it an older or newer saw??? if its older does the carb have a big or small bore (you can tell because the Big carbs have 3 screw holes on the filter side) one on the left, one on right, and one on the top in the middle...if this doesnt help...Let me know and ill try again!

350Xrider
01-16-2003, 09:48 PM
I wouldn't hit you in the ass with a McCulloch, they have and I guess always will have this problem. I have had about 4 of them and I personally had the exact same problems as you are experiencing, I gave them all away, and got smart and bought a Homelite.

4cylinders
01-16-2003, 10:48 PM
before you waste a lot of time, do a compression test. if it doesn't have at least 100 psi, it may not be worth repairing. mac went out of business about 3 years ago. if it has comp, run it till it quits, then check comp again. it may have dropped. if it didn't, you may just be getting vapor lock. todays gas is formulated for fuel injected vehicles. :rolleyes:

Dirtcrasher
01-17-2003, 09:47 AM
Hey,
I have alot of these motors....some came off saws, others were made specifically for racing.....it appears to me that the McCulloch Carburetors will eventually stop working.....no reason...they will just stop! we use tillotson carbs on our motors....but for the Mcculloch carbs initial adjustment is as follows: Open Idle fuel needle 1 1/4 turns out, and main fuel needle 1 1/2 turns out, then when engine is warm, adjust from there....Do you know what kind it is?? McCulloch i know, but like a Mc-2, is it an older or newer saw??? if its older does the carb have a big or small bore (you can tell because the Big carbs have 3 screw holes on the filter side) one on the left, one on right, and one on the top in the middle...if this doesnt help...Let me know and ill try again!

Its a 16" 35cc saw, I think model 3816. Itty bitty little carburetor. You say idle fuel and main fuel? They are labeled L and H. I thought low and high mixture screw?? It is about 5 yrs old and has cleared 500+ trees on 2 acres. But it USE to work well!! I think I need to check compression when its hot.

Dirtcrasher
01-17-2003, 09:49 AM
I wouldn't hit you in the ass with a McCulloch, they have and I guess always will have this problem. I have had about 4 of them and I personally had the exact same problems as you are experiencing, I gave them all away, and got smart and bought a Homelite.

I also had 2 used McCrappa saws which also wouldn't start when hot, although both of these had really scored aluminum cylinders and pistons so I tossed them. My cylinder looks good?

01-17-2003, 05:26 PM
Yes dirt....those are the high and low idle screws

01-17-2003, 05:46 PM
Sometimes the crankshaft seals will start to go and do just what your talking about, runs good one moment then wont start the next, I had it happen to a Poulan 16" woodshark, then I bought a huskie 50, world of diffrence.

Dirtcrasher
01-17-2003, 05:55 PM
Yes dirt....those are the high and low idle screws
You mean mixture screws not idle right??
Out for more fuel or what??


ATC Krazy, I did upon teardown of this saw see that there is a few thousandths of play in the main journals, up and down. Hell those cheap flucks ream a hole in the aluminum and that is the bearing! Yeah I know - get what ya pay for. What does that do? Screw up the air gap on the ignition I assume??

01-17-2003, 10:06 PM
Well if you get worn seals air will get sucked into the crankcase and leanout the mixture, bad for the cranks and make's hard starting(im not sure why it makes hard starting) or like on my 71 moto ski snowmobile it started to leak and spray oil/gas onto the points, makeing it hard to start. Seals are one of the most importent parts of a 2 cycle. But I dont know much about 2 strokes so my geuss is as good as yours.

FullBore
01-20-2003, 04:30 PM
I fix saws for a living, We always have trouble with Mc Cullochs, Don't buy one! It is most likely to be Worn rings/scored barrel, Crank seals or have you tried a new plug in it?

My advice is to scrap it and buy either a Stihl or a Husqvarna

Nat ;)