# McCulloch Mac Cat 2.3 start/run problems



## luckyvision (May 24, 2007)

Hi, here's the problem:
co-workers boyfriends saw, he rebuilt the carbs, but it'll only start with a shot of carb cleaner in the choke.

i looked it over, found the carb screws loose, & the choke plate slightly bent, fixed that.

the choke wouldn't close completely because it was hitting one of the screws, i swapped the 2 screws (different heads on 'em
) and it closes completely now (should it? or should there be a slight gap..1/16th inch or so?)

still wouldn't start so i tried it his way, slight shot of carb cleaner.
it started up & it ran too fast. i adjusted the idle, hi & low screws, & it didn't improve much.

if i hit the trottle it'll stall too.

i reset the hi & lo screws to i.5 turns out from lightly seated & i can get it to idle but it'll die easily.

i have a sneaking suspicion that the throttle cable might be sticking & it's not really returning to idle.

couple of other things:
the throttle pin thing (forget what it's called) only holds the throttle open a tiny bit, is this right or should it be open all the way? (i usually start a 2 cycle on full throttle) i tried to hold the trottle trigger open & start it, but it has good compression & dangerous to hold it that way while pulling the rope.

he had carb rebuild parts left over, don't know if he didn't bother changing them or if they fit other carbs too. (haven't gone into it that far)

fuel lines & filter look good for a quick inspection, haven't looked closely yet.

haven't pulled the exhaust yet either, but i will to check it if you think it's a possability/good idea. (is there a gasket for that, if so, can i use gasket material to replace it if needed?)

sorry for all the q's but i like to be detailed.

she's going to pay me something for fixing it (i told her not to..) but i haven't been able to find a manual online for it either, & it'd probably cost more to get it than what she's going to pay me (i doubt i'd take more than $20 from her anyway, she's hot!  

thanks for any ideas!! --Lucky


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## hdman97 (May 25, 2006)

No telling what happened inside the carb.
I'd start over clean and rebuild carb or look for a new carb.
Sorry but I don't think he knew what he was doing.


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## 30yearTech (Sep 14, 2006)

Could still be a carburetor problem, or also sounds like there is an air leak possibly between the carburetor and insulator or insulator and cylinder.

Be sure to check that the fuel lines are hooked up properly, or if this is a model with a rubber intake manifold this could be the source of an air leak as well as the fuel pump pulse hose if so equipped.


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## luckyvision (May 24, 2007)

*update, still need help*

finally had time to mess with it today.
original complaint after the owner rebuilt the carbs was that it would only start with a shot of carb cleaner, which i confirmed (would only start this way for me, then ran decent)

i rebuilt his carbs again today.let me mention i'm a well qualified mechanic, so rebuiling carbs isn't a big deal for me, but i have minimal experience with these little 2 cycle carbs.

here are the results: i believe the carbs weren't sitting well on the intake before this, also i found the hose from the carb to the engine hard & cracked. (thought i had it licked at this point!)
i pulled the exhaust, the screen looked good & i didn't notice any scoring on the cyl walls.

i assembled the carbs without the a/f cover so i could see what was going on, choke & all intact, except the throttle locker (on the a/f housing)

the saw would only start on full choke & full throttle, wouldn't idle but would scream at full throttle... fiddling with the H & L screws didn't help, it blows lots of oil out the exhaust (i added a little bit of straight gas, but probably should drain it & put in fresh 2 cycle.)

once warmed up i can only get it to start no choke, part throttle, it'll only run, badly, at part throttle. 

any more ideas? the rebuild went fine, there are some small scratches by the 3 holes that lead from the throttle bore to under the cover (plug) on the carb, but the holes are clear. there were marks under the plug from whoever removed it before with either a drill or screw...

thanks, --Lucky


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## luckyvision (May 24, 2007)

*a little more*

after dinner i pulled the plug, kinda dirty & a little wet, i cleaned it up, gave it a quick file (what should the gap be?) got some compression with my finger on it (it was hot, so i couldn't do it too long.) i have a compression tester, maybe i'll dig it out & tell you exactly what it is.

i discovered there were two gaskets together on my bench, i had only installed one so i pulled it apart & put the other one in (Doh! it looked like one when it came out)

running it does just about the same thing. i get bits of fuel spitting *out* the carb, & it'll run, idle like only at full throttle. btw, i can close both l & h screws off & it'll run like that. seems like too much fuel. i'm gonna go pull the carbs off for a 3rd time (the charm i hope)

thanks
--Lucky


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## luckyvision (May 24, 2007)

VICTORY!

after thinking about how there was a lot of gas spitting back thru the choke i decided to pull it apart again. i found the little plug i had replaced to clean out the carb had come loose. i staked it in with my automatic center punch & put it back together. ONE PULL started right up & idled Whoo hoo!! 

a tweaked the h, l & idle a bit, went out to the backyard & cut thru a few logs. runs like a champ.

now what do i charge 'em (co-workers husband) $50? more? less? killed my whole day off on it, but that would have been less if i was more experienced.

thanks, --Lucky


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## hdman97 (May 25, 2006)

All Right!! 
What to charge could be a tuff one.
With all the cheap new saws out there now,some are only about $80.
Maybe have em pay you for the parts and a fish fry with some cold ones.
hehe :lol:


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