McCulloch Chain Saws

[MacAttack]

The wintergreen oil and alcohol worked AMAZING at restoring the hardened rubber sparkplug cover!! Would highly recommend for any hardened vintage rubber parts. It's as pliable as brand new.

 

[Okie]

Hi,

I completely cleaned out the tank before I assembled the saw. How do I clean the metal filter, it doesn't seem removable? Can I spray it with carb cleaner and blow compressed air through it?

Thanks!

I'll clean the filter in the flatback and see what happens, it's possible that it's plugged with varnish... thanks guys!

Be careful and do not break it.
Yours looks like it probably not user friendly for safe removal. At first try spraying it with a cleaner and then place a white paper tower over the inlet barb and spary about 30-50 lb's of compressed air back through from the outlet side of the filter and catch the debris in the paper towel to get an idea if it contained any dried varnish or debris. If seeing varnish or molasses soak it in a cleaner and go again until it comes clean as viewed on the paper towel. I really have to be careful with the ones in the Tillotson carbs for removal. I use a sharp o ring pick and carefully go around the edge.
If you flatback don't come around you have the option to convert to the Tillotson type MAYBE.
I've converted to the Tillotson from the Mac carb but not sure about the flatback. It's been few moons back when I was doing such.
Also what I like about the Tillotson's is I could removed the breather stud on top of the carb and do a fuel pump pressure test while cranking the saw to see if it was priming itself and kitting the Tillotson was user friendly. you do have to get the proper Tillotson type for your choke set-up
heimnnan would know the details about such.
I had to change the carb linkages. I think I got the mac Tillotson replacement stuff from chainsawr.com

 

[Okie]

vinnywv:

I see several types of Goof Off.

What type do you prefer as a carb cleaner? (maybe a amazon link would do as to the type)

 

[Jethro 2t sniffer]

Cheap 805 in the for sale section

Basket case for sure but handy bits n bobs for 75 bucks

 

[MacAttack]

Be careful and do not break it.
Yours looks like it probably not user friendly for safe removal. At first try spraying it with a cleaner and then place a white paper tower over the inlet barb and spary about 30-50 lb's of compressed air back through from the outlet side of the filter and catch the debris in the paper towel to get an idea if it contained any dried varnish or debris. If seeing varnish or molasses soak it in a cleaner and go again until it comes clean as viewed on the paper towel. I really have to be careful with the ones in the Tillotson carbs.
If you flatback don't come around you have the option to convert to the Tillotson type MAYBE.
I've converted to the Tillotson from the Mac carb but not sure about the flatback. It's been few moons back when I was doing such.
Also what I like about the Tillotson's is I could removed the breather stud on top of the carb and do a fuel pump pressure test while cranking the saw to see if it was priming itself and kitting the Tillotson was user friendly. you do have to get the proper Tillotson type for your choke set-up
heimnnan would know the details about such.
I had to change the carb linkages. I think I got the replacement stuff from chainsawr.com

I have a Tillotson HL63E that came out of a junk Mac 250 that I'm in the process of cleaning and rebuilding, I have all the throttle and choke linkage, intake adapter, etc for a clean swap.

Thanks again!

 

[vinnywv]

 

[Okie]

Little bit of info from experience with the Tillotson and Mac's.
The HL63E and D are interchangeable and both have the spring loaded choke butterfly in the carb and use a RK-88HL kit. The little round cork gasket that is on the inlet side of the carb (on the sintered iron filter side) is quite often the wrong size for some carbs in the kit, therefore I'm careful to try to save the old one. I can usually remove the plate by pecking on the cover or pre-soaking the carb. It usually re-seals good if not torn. The cork gasket is not user friendly to make a replacement. Do not use high pressure air around a Tillotson or you will unseat the welch plugs or completely loose them into orbit. The Tillotson are just more user friendly for me to work on and get kit's, etc.
You probably already know this, be very careful when installing the carb and make sure all the intake adapters are properly seated or you can easily break off a ear at the carb mounting when tightening the bolts. I've never broke any but have seen where Bubba's have done such by not paying attention to the intake alignment lips.

Some 250's use a HL63F and uses a RK106 HL kit but I'm not familiar with this carb.

The reason I mentioned that you have to keep a heads up about choke arrangement is the HL83D carbs DO NOT HAVE a choke butterfly in the carb.

Every once in awhile I see what appears to be a good re-buildable HL63E or D on fleece bay at a reasonable price, but I stay away from the ones that have mutilated screws that Bubba has been into. I keep couple good Tillotson carbs set back as spares for my Mac's.

 

[MacAttack]

Okie, that's an excellent summary of info on the Tillotson carbs, thank you!

My only question is about this cork gasket you speak of...i took my HL63E all apart but did not see a cork gasket?? Are you referring to this funny shaped gasket on the filter? Or is it the round gasket on the bottom cover?

 

[Okie]

Round one on the bottom cover. The diameter of the gasket is sometime wrong size from a new kit.
It's called the fuel strainer cover gasket. It appears it's not cork on your carb.
The ones I've been into were cork.
#18 on a parts diagram.

Here is a link to the Tillotson carb site. You can find parts lists and service info for the HL carbs and several others.

https://tillotson.ie/products/illustrated-parts-lists/

 

[sean donato]

@Okie the tilly i have is an hl19D which i belive is off a 1-70 originally, it has the choke butterfly, which in my case needs the linkage modified, but the throttle is the same set up as the flat back w/ govenor fork on the one side.

 

[MacAttack]

Installed the Tilly style throttle linkage and choke button with the locking mechanism.

I'm going to try the saw with the Tillotson (once I get my rebuild kit) and go from there.

 

[Okie]

If that black fuel hose is the OEM which is dry hard and the OEM clamp it's another source of starving for gas when in a cut. I use a itty bitty host clamp that can be tightened with a 1/4 inch drive or screwdriver and replace the hose.

If you see fuel in the air box it's usually a hint it's sucking air and leaking at the hose barb.

 

[Okie]

@Okie the tilly i have is an hl19D which i belive is off a 1-70 originally, it has the choke butterfly, which in my case needs the linkage modified, but the throttle is the same set up as the flat back w/ govenor fork on the one side.

The Tilly that had no choke butterfly in the carb such a the HL87D was used on some old Mac's and the choke is a big plastic round button that blocked the carb throat air supply when choked.
The tilly HL63D and E can be used in place of the D but not vice versa unless the proper choke mechanism is used.
I'm not familiar with the 19D but good to know. I'll review and add it too my Mac carb note file.

 

[MacAttack]

If that black fuel hose is the OEM which is dry hard and the OEM clamp it's another source of starving for gas when in a cut. I use a itty bitty host clamp that can be tightened with a 1/4 inch drive or screwdriver and replace the hose.

If you see fuel in the air box it's usually a hint it's sucking air and leaking at the hose barb.

Fuel line is brand new

I did install the OEM clamps which seem ok, but if I still have problems I could replace with clamps.

 

[Jeffrey F.]

Fuel line is brand new

I did install the OEM clamps which seem ok, but if I still have problems I could replace with clamps.

Installed the Tilly style throttle linkage and choke button with the locking mechanism.

I'm going to try the saw with the Tillotson (once I get my rebuild kit) and go from there.

View attachment 1218063

I have a kit you can have I think it's the one you need. I'm not sure but swing by tomorrow on the way home you can have it.

 

[MacAttack]

I have a kit you can have I think it's the one you need. I'm not sure but swing by tomorrow on the way home you can have it.

I was very kindly given a Tillotson carb kit along with a printout of a McCulloch Flatback shop manual by Jeff today, thank you sir!

so I'm looking through the pages and what's this?? A rubber one-way duck valve in the impulse passage? If this is located somewhere inside my Mac Flatback carb, it is almost certainly hardened up and my guess is not allowing the crankcase pulses to make the carb function properly....

 

[heimannm]

That duckbill valve (same one used in the fuel cap for the large frame saws) is only found in the BDC "pressure pulse" carburetors and is not used on the MAC models.



Mark

 

[MacAttack]

Ahh ok, thanks Mark, I didn't realize they were 2 different models of carbs. I thought I found my "smoking gun"!

Any-who..... next step is to rebuild my Tillotson HL63 and see if it brings my 450 to life finally.

 

[bob kern]

Tank was about a third full. I did notice the fuel line going to the filter seemed a bit stiff and it made me wonder if the filter was not dropping into the gas when the saw was on it's side?

I have definitely had that issue before. Anymore the second I hear any change in my saws, I stop and fill up regardless where the level is. I've found filters stuck up in a corner and all kinds of crazy stuff.

 

[bob kern]

Lost a keeper on the choke rod for my pm 1000. Made a replacement out of plumber strap with a carefully sized hole drilled in it. I used a small punch to make some indentions around the perimeter of the hole to give it some friction . Don't know if I've seen one this small , but I'll be checking on my next trip in . Hope this holds for now.