MAC 3200 will not start

[ggratecc]

HI,
Current status: I removed the H/L limiter screws, then cleaned and reassembled carb using instructions from ZAMA, as far as gas pump side and nozzle side.
Put it back in the saw.
At first pumping the bulb did not work, so I pulled the rope a few times and then got fuel to flow with primer system.
Unfortunately, I can not get it to start at all now. Also, fuel is leaking out of the muffler when pulling rope.

stumped.
Greg

 

[dougand3]

You need to see needle move upward ~1mm when you push lever. Needle tip and seat are probably damaged or full of gunk/varnish. Need to remove screw, spring, lever and needle to see. Sounds like bad flooding. Spoon is welch plug. It must firmly attach all around the 3 holes. Rounded side up. Some use nail polish to secure seal but I'd rather have a new plug. 1st pic has 2 fuel pumps - just need 1. Fuel pump against carb, gasket against plate.

You must get a rb kit for any hope of this carb delivering fuel in a proper manner. Another option is finding a similar carb for $10 on ebay and adapt. May have to change choke rod/plate from old to new. May have change throttle rod/plate or drill a new throttle link hole. I've used a coat hanger as a choke pull.

Look your carb over. Compare to "chainsaw carburetor" search on ebay. Poulan 1975 or 2375 or Husqvarna 142 (no purge circuit, tho) may work.

 

[cpurvis]

I am not an authority on diaphragm carbs but it looks to me like it goes concave side down.

 

[ggratecc]

You need to see needle move upward ~1mm when you push lever. Needle tip and seat are probably damaged or full of gunk/varnish. Need to remove screw, spring, lever and needle to see. Sounds like bad flooding. Spoon is welch plug. It must firmly attach all around the 3 holes. Rounded side up. Some use nail polish to secure seal but I'd rather have a new plug. 1st pic has 2 fuel pumps - just need 1. Fuel pump against carb, gasket against plate.

You must get a rb kit for any hope of this carb delivering fuel in a proper manner. Another option is finding a similar carb for $10 on ebay and adapt. May have to change choke rod/plate from old to new. May have change throttle rod/plate or drill a new throttle link hole. I've used a coat hanger as a choke pull.

Look your carb over. Compare to "chainsaw carburetor" search on ebay. Poulan 1975 or 2375 or Husqvarna 142 (no purge circuit, tho) may work.

Dougand3,
This is great, just the info I was looking for.
I did everything you mentioned in your first paragraph, but unfortunately have similar results, not starting, but less gas leaking. Thus I am giving up on it.
I found those Poulon compatible models you suggested, but think I will try this one from Amazon:
https://www.amazon.com/gp/product/B07MR29YS4/ref=ox_sc_act_title_1?smid=A19FM3LXB9B8NR&psc=1

Even if the choke plate control is on the wrong side, I like your idea of using a coat hanger!

I'll update you, when I get the new carb and installed.
Greg

 

[dougand3]

Yeah, that's the same carb and you get other stuff, too.

 

[ggratecc]

Yeah, that's the same carb and you get other stuff, too.

Dougand3,

See photo, the carb I bought did not fit on the cylinder side opening, due to the two alignment tits on cylinder do not have any place to go on the
carb! As you can see the original cylinder gasket is shown with the two tits.
So far I can't find a carb that will seat on the cylinder, any ideas? I keep looking at the C1Q body but can't find one like this.
thanks,
Greg

 

[bertsmobile1]

HI,
Current status: I removed the H/L limiter screws, then cleaned and reassembled carb using instructions from ZAMA, as far as gas pump side and nozzle side.
Put it back in the saw.
At first pumping the bulb did not work, so I pulled the rope a few times and then got fuel to flow with primer system.
Unfortunately, I can not get it to start at all now. Also, fuel is leaking out of the muffler when pulling rope.

stumped.
Greg

Going back to the beginning
The carb has to be airtight or it can not work.
The primer "sucks" air out of the system and "sucking" is not as effective as pushing so it can take 30+ pumps to get the fuel flowing.
The pin on the metering diaphragm points down to the lever.
The major difference with the diaphragms is the length of this pin.
The needle is closed by a spring and my guess is that you have omitted the spring or it has displaced sideways.
Never ever seen a cube carb with a locating pin on the face.
Are you sure that you have not misplaced a spacer ?

 

[dougand3]

So, the original carb has 2 special holes that accept with the 2 gasket retainer nipples? Then, carb can slam tight against the gasket all the way around? Seems like over-engineering. Doubt you'll find a new "nipple ready" carb.
Everybody else just puts 2 screws thru air filter housing and carb, mounts gasket on screws, then mounts carb by screwing in. Make sure sequence is intake impulse hole---gasket hole---carb impulse hole. Pic looked correct to flip carb on.
I'd trim nipples off flush with the rest of intake surface and mount carb. You need an airtight seal here. May need new gasket if old one is compressed too much.

 

[ggratecc]

So, the original carb has 2 special holes that accept with the 2 gasket retainer nipples? Then, carb can slam tight against the gasket all the way around? Seems like over-engineering. Doubt you'll find a new "nipple ready" carb.
Everybody else just puts 2 screws thru air filter housing and carb, mounts gasket on screws, then mounts carb by screwing in. Make sure sequence is intake impulse hole---gasket hole---carb impulse hole. Pic looked correct to flip carb on.
I'd trim nipples off flush with the rest of intake surface and mount carb. You need an airtight seal here. May need new gasket if old one is compressed too much.

Dougand3,
I came up with the same conclusion that I could grind off those two tits, the cylinder gasket is in excellent condition. It does seem all the impulse holes line up
as you said.
Q: if a bronze fuel line nipple is coming strait out of carb about 1/2", is it possible to bend it about 30 degrees?
thanks,
Greg

 

[ggratecc]

Going back to the beginning
The carb has to be airtight or it can not work.
The primer "sucks" air out of the system and "sucking" is not as effective as pushing so it can take 30+ pumps to get the fuel flowing.
The pin on the metering diaphragm points down to the lever.
The major difference with the diaphragms is the length of this pin.
The needle is closed by a spring and my guess is that you have omitted the spring or it has displaced sideways.
Never ever seen a cube carb with a locating pin on the face.
Are you sure that you have not misplaced a spacer ?

HI,
I would love to repair this carb, feel I have come close; spring, lever, pin work great - deflect about 2mm when I press on lever.
I suspect there is some other problem that does not come in a rebuild kit... the nozzle check valve.