• Online Events For Landscapers!
    With GIE+EXPO cancelled, virtual education and product launches are filling up the fall. Check out dates for Caterpillar, Exmark, NALP, and more. Click here to learn more.

mCculloch FR2.0

Buckshot06

LawnSite Member
Location
MI
I inherited a Mac chainsaw. FR2.0 - it runs, wide open. If you let off the gas at all it dies. I took the carb out of it, didn't find any major debris or anything questionable. I put it all back together brought the H and L needles about 4 turns out. I got it goin and adjusted the high till it sounded like it was doin okay. The low needle wont change the saws performance, even with it closed all the way up.

What do you guys think? Weak pump/diaphram?

Fuel filter is new - plug is good.

Thanks in advance.

Buck
 

bob91343

LawnSite Member
Location
los angeles
Did you ever get that chain saw working? I have one and the little rubber bulb you press to prime it has torn away. How do I get another, or fix this?

Not very good with tiny gasoline engines.
 

echoman8

LawnSite Senior Member
Location
west Texas
Hi,

About the bulb?

Below is a copy of a post a few days ago.

PURGE BULB DISABLE


I have had problems with the "so called" primer bulb on echos and other small 2 cycle engines.

The bulb does not prime the carb, it just loads it with fuel if it is empty. To do this, it has 2 rubber valves (duckbill valves). With age they quit working.

I remove the bulb, cut a piece of plastic (freezer bag), place between the bulb and carburetor housing, then put the bulb (and metal plate) on.

This disables the primer(actually purge pump) and you will have to depend on the choke to start (cold start only) just like it was in 1990 and before.

The duckbill valves allow air to enter the carb irratically (when bad).

de
 
Top