mcculloch super 250

[mg1944]

I have a really nice super 250.
rebuilt the carb on it because it would not start when it was cold without a prime and it still won't start.
you can pull it until you have a heart attack, and it won't start. give it a spritz of fuel and it fires right up and will run perfect.
what could be wrong with it?
its driving me nuts

 

[sawfun]

Does it have a choke or primer. Those primers are usually bad and hard to repair. Mark may have one if that's the issue. I have a 797 that is that way and had an 895 that did the same. I just squited mix in them when cold otherwise they didnt need it.

 

[mg1944]

Does it have a choke or primer. Those primers are usually bad and hard to repair. Mark may have one if that's the issue. I have a 797 that is that way and had an 895 that did the same. I just squited mix in them when cold otherwise they didnt need it.

well I figured out the problem.
I put the saw in the vise to investigate further and noticed that when the choke plunger was locked, the plate wasn't shut all the way. put my thumb on it to shut it, pulled it three times and it started right up. then I very carefully used a pointed pair of vise grips and an adjustable wrench to bend the choke rod flatter to extent it's length until it shut the butterfly when locked.
starts fine now. now i'm working on adjusting the carb.

 

[heimannm]

That is a very common issue with the old front tank saws. So easy to fix once you know where to look.

Mark

 

[Okie]

AND
quite often to save time when attempting to start a cold saw especially a old Mac that is coming out of storage I just dump a little prime into the muffler FIRST and not use the choke. Faster than looking for tools to remove air filter cover to prime the carb throat then re-installing.
Saves lots of time and the saw is ready for immediate use when it starts.

 

[mg1944]

AND
quite often to save time when attempting to start a cold saw especially a old Mac that is coming out of storage I just dump a little prime into the muffler FIRST and not use the choke. Faster than looking for tools to remove air filter cover to prime the carb throat then re-installing.
Saves lots of time and the saw is ready for immediate use when it starts.

 

[mg1944]

thanks
next question is how do I fix the auto oiler which was working perfectly and now does nothing?
and, does anyone happen to have a spare set of bar plates they are willing to part with?
my saw's plates were missing.

 

[FlyingDutchman]

The plates we got on ebay. I think the oiler uses crankcase vacuum and is pretty temperamental.

 

[mg1944]

The plates we got on ebay. I think the oiler uses crankcase vacuum and is pretty temperamental.

thanks, can you post a link for that on ebay? I've looked high and low and have not found them there.
Crankcase vacuum?
that sounds like a bad crank seal may be the cause of the oiler failure then.
frustrating, when I first got the saw running the oiler worked fantastic and made me think back to my clumsy super 44 days when I was a kid and the stupid push button choke you had to hold down along with the throttle to start it and the push button oiler that about broke your thumb off you had to pump nonstop once you did.
I thought..... "gee, this Super 250 is like driving a caddy..."
and then it quit...

 

[Okie]

You might consider asking around for a MAC factory SERVICE manual for your 250.
might even be one on this site?????????

I have one that I put on a CD that I thjnk maybe it covers all 1-40, 1-50 and the 250 series of saws. I think maybe it has around 250 pages of detailed info..
I think maybe I got mine from chainsawr.com few years ago as a download link. I had to buy it and they sent me the link from their site, but price was very reasonable, maybe about $5 and after downloading I sent it to a CD as back-up in case computer crashed.
It has all the how to's factory SERVICE adjustments for this series of Mac's. (and shows how to service their carbs including the old McCulloch made carbs)

Here is a link: BUT SEND THEM A EMAIL TO CONFIRM IF THIS ONE IS COMPATIBLE.:

https://chainsawr.com/products/mccu...and-repair-manual?_pos=7&_sid=fd8cb7b05&_ss=r

 

[snobdds]

Bar plates were hard find for mine. I think I ended up paying close to 60 for two plates.

Hopefully someone has a stash somewhere...

 

[mg1944]

Bar plates were hard find for mine. I think I ended up paying close to 60 for two plates.

Hopefully someone has a stash somewhere...

I may make a set for that kind of money.
not much to them

 

[Okie]

When looking for vintage chainsaw parts I usually also refer to the Chainsawr.com link so as to get an idea of prices, availability, etc.
They have good pictures of the parts usually.
I suspect that the 1-40, 1-50 Mac's use the same bar plates. (but not sure)

You might consider doing a SAVED search on fleece bay so as to get a email heads up notice if any bar plates are ever listed for sale.
I've noticed when the word VINTAGE is used the price is higher. My same type stuff when I'm selling, people call it junk instead of vintage.

 

[mg1944]

took a set of xl-12 plates and filed out the adjuster groove on the right side to allow the pin to slide through and they fit perfect.
next mystery is the auto oiler.
why oh why did it go kaput?
???

 

[heimannm]

For future reference, I have a good assortment of bar plates available for the large frame saws, including the older wide bars and later slim line bars.

Automatic oil pump failure is probably not due to crankcase seals, if the saw runs the seals are fine. It is possible the piston got stuck, that can happen from time to time. You might get by running some kerosene or ATF though with the manual oiler. If that doesn't fix it you are in for a major task as the automatic pump is located in the fuel tank. The automatic pump is everything from 27-42. I have the fuel tank gaskets and most other parts if you have to open it up. If the saw has a lot of hours, it is possible the thin phenolic disc they call the ring (33) has failed and is no longer driving the piston (31).

It is not really a vacuum operated pump, the crankcase impulse signal (alternating positive and negative pressure) causes the piston to move back and forth.



Mark

 

[mg1944]

thanks very much for the info
the saw is practically brand new, made in Canada, and the oiler was working perfect.
I think what I'll do is run it a bit using the manual oiler and see if God fixes it for me, then I'll try some atf or pb blaster in there. If that doesn't work, I am going to live with it because the saw is so nice that I really can't risk doing any work with it that could mess it up, so manual oil is just fine.
Think I'm going to sell it and get one that is at least a little beat up that I can relax with.
there is such a thing as TOO nice.