Hard starting reputation of McCulloch saws?

[TheManOfStihl]

I recently acquired a McCulloch 250 saw in pretty good shape for it's age. I like it, it's heavy but the 80cc engine gets work done. Only has a 16" bar on it for some reason, but I'm running it for now, not having any other Mac bars. I'm going to modify a Stihl bar one of these days, 28" maybe. This is planned to be my large tree felling saw. Hard to get used to manual oiling, this is my first saw that doesn't oil by itself too.

It starts and runs well, but after it's warm it takes 6-10 pulls to get her going again. I guess it's not a huge deal to me, I can live with that, I'm young for now. But many old timers have laughed at me since I got this saw, saying they are known to be real hard starters, and some die with no restart when they are warm, and you're done cutting until the saw cools. This is my first Mac, and I like it, so I tend to ignore them, but they keep telling me to sell it, saying "You'll see!".

I don't really want to sell the saw and I probably won't, but just makes me think. These old timers did run these saws back in the day. They do know what they are talking about usually. Does anyone have any supporting facts on this? I have read that the 250's came with either a Tilly or a flat back carb. Mine has a Tilly, so apparently that's the better one. But otherwise, if these old timers are correct, are there fixes for this type of thing? I'm a mechanic by trade, but until my saw messes up I can't do any troubleshooting to figure out what would be wrong. Open in the coil when warm? Any chance of a vapor lock with the fuel? Certainly someone knows what I'm talking about and can shed some light on the subject?

 

[TheManOfStihl]

View attachment 301705View attachment 301705

Here is my McCulloch 250. On the bench without the bar and chain right now for maintenance.

 

[IEL]

I guess I will know for myself soon. I just picked up that same saw yesterday, it is being torn down right now. Hope to have it running in a few days?
I have heard they are easy to start warm?

 

[TheManOfStihl]

Not sure, I've only had this two weeks now, and it starts easy cold, 2 pulls every time. but after I refuel it or shut it off for any reason, even if I rip the rope as soon as the engine stops... it's 6-10 pulls. I tried to choke it once, just to see...yeah, bad idea. Flooded the carb. But no choke and a number of pulls and it runs great again. I don't get it but I'm young so I can deal with that. Otherwise I like this one. I know she can handle a much bigger bar than the 16" that's on it, and someday soon she will.

 

[workshop]

I think the biggest problem was they didn't put a fast idle step on them.

 

[pioneerguy600]

They had a bad habit of boiling the fuel in the tank , a lot of all magnesium chainsaws had this problem. The flatback carb was also very finnicky to get tuned correctly, the Tillotson HL was a better choice.

 

[Warped5]

It starts and runs well, but after it's warm it takes 6-10 pulls to get her going again. I guess it's not a huge deal to me, I can live with that, I'm young for now. But many old timers have laughed at me since I got this saw, saying they are known to be real hard starters, and some die with no restart when they are warm, and you're done cutting until the saw cools. This is my first Mac, and I like it, so I tend to ignore them, but they keep telling me to sell it, saying "You'll see!".

Those guys also probably didn't have an air compressor to help keep the saw clean between uses. Caked up mungy is a huge contributor to overheating and hard starting. Not just for the Mac 250.

I think the biggest problem was they didn't put a fast idle step on them.

I sure agree with this!

They had a bad habit of boiling the fuel in the tank , a lot of all magnesium chainsaws had this problem. The flatback carb was also very finnicky to get tuned correctly, the Tillotson HL was a better choice.

Sure do! If you can ever swap in a Tillotson HL-63, do it. You'll be happier! Make sure you get the spacer plate.

 

[pioneerguy600]

Those guys also probably didn't have an air compressor to help keep the saw clean between uses. Caked up mungy is a huge contributor to overheating and hard starting. Not just for the Mac 250.



I sure agree with this!



Sure do! If you can ever swap in a Tillotson HL-63, do it. You'll be happier! Make sure you get the spacer plate.

The Canadian made 250`s came with Tillotson carbs.

 

[TheManOfStihl]

Mine must be Canadian made then, it has the Tillotson HL63G on it now. That's about as good as it gets on this saw, isn't it?

 

[pioneerguy600]

Mine must be Canadian made then, it has the Tillotson HL63G on it now. That's about as good as it gets on this saw, isn't it?

Yup!

 

[workshop]

Hey Warped5, Do you know of a source for a tillotson HL19D kit? Been looking around some but can't seem to locate anything. It's on a 1-70. Saw is in great shape but diaphragm is stiff as a board.

 

[Warped5]

Hey Warped5, Do you know of a source for a tillotson HL19D kit? Been looking around some but can't seem to locate anything. It's on a 1-70. Saw is in great shape but diaphragm is stiff as a board.

Howdy, Workshop!

That would be an RK-44 kit. There's one on eBay right now: Vintage Tillotson Carburetor Repair Kit RK 344 for HL 19A HL 19B HL 19c D | eBay

You might find it cheaper at an OPE shop near you.

Good luck!

Promac850 once posted a thread on 'priming' these carbs during re-assembly, I swear it does work.

 

[workshop]

Awsome!!!!! Thanks, you

 

[leeha]

I've seen a ton of 250's with the HL63 carbs.
If your carb hasn't been rebuilt the diaphrams could
be a bit stiff and holding the needle slightly open or
the needle itself could be bad and causing it to flood
when shut down. Causing hard start problems when
warm.




Lee

 

[heimannm]

Hard starting cold problems were normally:

1) Old, stiff diaphragms, easily solved with a carburetor kit
2) Choke not closing completely, easily repaired with an adjustment to the linkage

Hot start problems were typically boiling fuel as Jerry noted. Three possible solutions were:

1) Never shut it off (easy to refuel while running since the fill cap is large and on top)
2) Let it cool down, refill with fuel, and make sure the cold start issues were properly dealt with
3) Prime it down the throat and hope it was enough to pull fuel from the tank, otherwise repeat the prime process

I cut a lot of wood 30-40 years ago with nothing more than a McCulloch 250 equipped with a 19" bar. I was a lot younger, better fit, and slightly less knowledgeable than I am today.

Mark

 

[Saw Dr.]

In addition to what Mark said: Marginal compression, mis-adjusted ignition, and/or air leaks can all cause hard start issues as well. Properly set up, that saw should be easy to start. McCulloch sold a mountain of those. I'm sure they would not have if nobody could get them started.

 

[Nickolas]

I will have to disagree with most about the carb choice. I'll take a flat back any day over a tillotson. Sometimes you have to mess with them a bit to get them right but there are other carbs the same way. I love the primer flat back carbs as they make it very easy to start the saw. One or two pulls and im running every time. With a regular choke carb I am pulling several times to suck the gas up to it. The flat backs work great when tuned properly just as the tillotson. I think it is all a matter personal preference. I hear so many say then swapped out the flat back for the tillotson and I really see no reason to do this at all. Sure the kits are a little more expensive but they are good carbs. My Super 250, 440, 740, 797 all run great with primer flatbacks on them.

And keep your saw tuned and clean. Seems most every saw I get the fins are clogged and the points are a little toasty. Another thing is the bars are also full of crud and wont let the oil flow properly to lube the chain. I have had to clean nearly every bar I have bought and scrape a lot of crud from it. I have always been one to do prevenative maintenance and it goes a long way... I wont be the one in the woods pulling and pulling on the rope and cussing my saw... You will see me pull it a time or two and i'll be in the wood with chips flying... Anyway I think if you keep your saw tuned and clean you wont really have any issues with it. And another thing is use NON ETHANOL gas if you can get it. Makes a HUGE difference. Around here we have it all over and I will not use ethanol gasoline anymore. It really makes a big difference in how your saw starts and runs... And you dont have to worry about phase seperation which is a freakin headache... I have several boats all with two stroke outboards and I will NOT buy gasoline with ethanol in it... Pure gasoline makes them run like they should... Buy it if you can and you will see the difference...

Nick

 

[Gearhead1]

I think the biggest problem was they didn't put a fast idle step on them.

I have found it often helps for hot starting to find a log to lay the saw on and use one hand to squeeze the throttle open while pulling with the other.

 

[Philip Wheelock]

My (older) friend said that they used to prime the old McCullochs on cold days by dumping some fuel mix in the exhaust. Said the results were quite entertaining.

 

[heimannm]

Yes