# McCulloch 3227 carb adjustment



## charlesaa81

I have a mac 3227 weed wacker that I purchased new 10 years ago. this year I replaced the fuel lines and spark plug. when I start it on choke it will run for about 5 seconds then I switch to start and it will run for 10 to 30 seconds. when I try to pull the throttle trigger it boggs down and stalls out.
please help


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## bbnissan

If it bogs down like it's getting too much fuel, turn the low side screw out about 1/8 of a turn at a time until it will rev without bogging. If it bogs down like it's not getting any fuel, you probably need to open up the high screw a little. 

BTW, you can determine which screw is which by looking at the carb at the base of the screw...it will have a L for Low or H for High stamped near it.


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## charlesaa81

*thankyou*

that worked like a champ thanks to your help I was able to finish my yard today!


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## Logger

I have a similar problem, but there is nothing stamped on the Zama carburetor. I did a poor-boy rebuild, and now it starts but wont rev as high as it used to. Which screw is the low & which is the high? I would think the one nearest the throttle plate is low and the one nearest the venturi is high, but am not certain. 

I thank you in advance.


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## hankster

The screw closest to the engine is the low end adjustment.


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## OldPro

*Where to start?*

Old weed whacker. Cleaned carb and replaced throttle cable. Starts sometimes! When cold is easiest. Question: Starting from scratch, how many turns from the bottom do you set the Low and High screws? 

Thanks!


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## hankster

The old units normally should start out 1 1/2 turns from fully closed.


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## OldPro

Thanks I will try that.


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## Z33ky

I'm the original owner the my MacCulloch 3227 and the owners manual says 1994 so I must have had it since 94 or 95 and it's performed very well for me all these years except recently.

My problem is that I have to keep pressing on the throttle trigger or else my 3227 will die and even after I do that for a while the 3227 will just quite. 

The High/Low screws on the carb are the fuel/idle mixture screws correct? 

According to bbnissan's previous comment on this string:


bbnissan said:


> If it bogs down like it's not getting any fuel, you probably need to open up the high screw a little.


I've never touched the high/low screws on my Zama carb all these years but I suspect the carb needs adjustment. I turned the high/low screws all the way in just to see how many turns out they were and the results are:

The Low screw 1 1/4 turns out. 

High screw was 2 1/2 turns out. 

I've cleaned the carb by taking it apart but putting it into a carb cleaner bath and I also replaced the fuel lines which had become stiff and cracked.

Should I just open the high screw a little? Thanks in advance!


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## Z33ky

*How To Professionally Adjust Zama Carburetors?*

Well I got my little screw driver out and decided to make the carburetor adjustments myself and just do the trial and error routine and when I opened the High screw it made matters worse so I turned the High screw in a 1/4 turn and that did the trick and the 3227 was able to run a idle with choke off and my finger off the throttle trigger. 

If anyone can instruct me on how to professionally adjust the high/low screws on this Zama carburetor I'd greatly appreciate it. There are no limiting stops on my High/Low screws.

The idle screw is separate from the High/Low screws so the idle speed has nothing to do with the High/Low screws so the High/Low screws must be all about carburetors’ fuel mixture. Thanks in advance!


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## geogrubb

I think normal procedure is to start with both L and H at 1 - 1 1/2 out from seat then adjust the High so the engine runs its best at WOT(Wide Open Throttle) then back it off until it just starts to sound like a 4-cycle, if you don't back it off it will be too lean and burn it up, then adjust the low at "not" WOT until the engine runs the fastest and smoothest then adjust the idle using the throttle linkage screw. Have a good one. Geo


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## Z33ky

geogrubb said:


> then adjust the low at "not" WOT until the engine runs the fastest and smoothest then adjust the idle using the throttle linkage screw. Have a good one. Geo


Thanks geo!

When you wrote; "...then adjust the low at "not" does "not' mean 'Not Open Throttle' or at idle speed? I'd read on other posts that the low screw is to be adjusted when the motor is idling.

Thanks again,

Z33ky


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## geogrubb

Yes adjust the Low at idle. Have a good one. Geo


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## langlin

I have a Mcculloch FR4618 that I had to replace the fuel lines on. It now runs good, cuts under load but it idles way too fast, the idle screw is all the way out, I believe the hi and low adjusts are right.

Thanks for your help in advance.


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## langlin

langlin said:


> I have a Mcculloch FR4618 that I had to replace the fuel lines on. It now runs good, cuts under load but it idles way too fast, the idle screw is all the way out, I believe the hi and low adjusts are right.
> 
> Thanks for your help in advance.


I forgot to ask, does anyone have an idea why the saw idles very fast and won't idle slow?


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## geogrubb

First check to see that the linkage is not binding somewhere not allowing the carb butterfly to close, second while it is idling spray some carb cleaner behind the carb along the mating surfaces to see if the engine tempo changes, if it does you have an air leak. Have a good one. Geo


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## kwando

what is the fuel mixture for the 3227?


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## Fat Tony

langlin said:


> I forgot to ask, does anyone have an idea why the saw idles very fast and won't idle slow?


Sure to be an air leak.


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