MAC 3200 will not start

ggratecc · Oct 24, 2019

Hi guys,
I have a McCullough MAC 3200 with a
symptom: will not start

Here are some photos:

I have fresh gas in the tank, bulb priming seems to work fine, checked sparkplug it looks new;
removed the muffler, closed the choke.

Tried pulling the rope and there are no sounds of it starting.
Tried engine start fluid , that did not work.
Tried different choke settings.

I tried adjusting the throttle screw a bit, nothing.
TIA,
Greg

dougand3 · Oct 25, 2019

Best to use fuel mix, not starting fluid, in 2 cycles. You wash the lube off cylinder & piston.
1. Pull plug, put tsp of fuel mix in hole, re-install plug/wire, pull rope 10-20x. If you don't get a pop and maybe a 2 sec run, then you have a compression or spark problem.
2. Pull plug and ground metal side on engine. Pull rope and look for spark. Even with good spark - it could be at the wrong time - As in, flywheel sheared key.
2. Hold pull handle and let saw drop. Lug..........Lug..........Lug is good compression. Lug..Lug..Lug is bad.

ggratecc · Oct 25, 2019

Dougand3,
Thanks very much for your excellent reply!
Performed step 1.: after 20 pulls , the engine started right up and ran for about 15 seconds, then stalled.

So, then I'm thinking fuel system problem...
I pumped the bulb about 4 times and then pulled a few times and it ran again for 12 seconds and stalled.

Then, I noticed when I pushed the bulb, the fuel started gushing out of the top of the carb choke!!
I studied the way the fuel hoses run, took photos and made a crude drawing, see photos:

I think I know what to do next, but i'd rather you guys tell me which hose goes where on this Zuma!
I hope that I am describing the carb front and back properly...I'm describing carb front as being the side where the idle adjustment screw is.
TIA,
Greg

dougand3 · Oct 25, 2019

Long hose with filter goes directly to carb nipple that is closest to the fuel pump side (1 BIG screw plate). Been so long, can't remember which side.
Long tube of bulb goes to fuel tank. Short bulb tube goes to other carb nipple.

ggratecc · Oct 26, 2019

dougand3 said:
Long hose with filter goes directly to carb nipple that is closest to the fuel pump side (1 BIG screw plate). Been so long, can't remember which side.
Long tube of bulb goes to fuel tank. Short bulb tube goes to other carb nipple.

Hi,
As you described I was able to reroute the three fuel lines properly, prime bulb worked fine and drew fuel through carb and back into tank!
I got it to run smooth for a minute or so, then stalled.
I got it started a second time also, then stalled quicker.
Then what I tried to pump the bulb , NO fuel is moving in the lines at all!
So I rerouted the fuel lines to by pass the carb , pumped bulb again and fuel flow just fine back to the tank.
My conclusion is the carb is in a state that will not allow fuel to be sucked through it, clogged?

Here are photos of the zama:

Any ideas? should I buy a new Zama carb? All I know is that it is a 32cc McCullough - MAC 3200. Anyone have a link to a carb replacement?
Does anyone think I can clean the carb and retest it? Do you recommend a rebuild kit? I feel comfortable taking it apart and rebuilding.
TIA,
Greg

dougand3 · Oct 27, 2019

Pull the carb and read the #s. Maybe C1U-M35? Old carb that will be be NLA. Search ebay for "Mac 3200 carburetor" , "Zama CIU rebuild kit". You can try a thorough cleaning and rebuild kit but not always successful. You can search ebay for similar carbs and compare to yours - linkages, impulse hole. May find a similar enough carb to work.

ggratecc · Oct 27, 2019

dougand3 said:
Pull the carb and read the #s. Maybe C1U-M35? Old carb that will be be NLA. Search ebay for "Mac 3200 carburetor" , "Zama CIU rebuild kit". You can try a thorough cleaning and rebuild kit but not always successful. You can search ebay for similar carbs and compare to yours - linkages, impulse hole. May find a similar enough carb to work.

Thanks again for your reply...
It is a C1Q - M36 I discovered! So far I have not been able to find one of these in-stock. I will look for a similar one as you say.

I might just do a rebuild as you say, depending on what I find on similar carbs.
Q: if I clean and rebuild, should I remove the H and L adjustment screws?

Greg

dougand3 · Oct 27, 2019

yes, gotta remove H&L screws. Turn In/CW first (light stop at end). Note how many turns to stop. Eg: 1.5, 1.25, 2.0. This is "turns out figure".
Impulse hole is on cylinder side of carb. Can be at 12 o/c, 10 o/c, 2 o/c. Look at the intake adapter - there will be a matching hole there. A new carb needs hole in the same place as old carb. (Some carbs have a 90* nipple w/ tube on fuel pump plate - but that's another story)

ggratecc · Oct 28, 2019

dougand3 said:
yes, gotta remove H&L screws. Turn In/CW first (light stop at end). Note how many turns to stop. Eg: 1.5, 1.25, 2.0. This is "turns out figure".
Impulse hole is on cylinder side of carb. Can be at 12 o/c, 10 o/c, 2 o/c. Look at the intake adapter - there will be a matching hole there. A new carb needs hole in the same place as old carb. (Some carbs have a 90* nipple w/ tube on fuel pump plate - but that's another story)

OK, took out the h/l screws, took carb apart, see photos.
I'm concerned about two things before I put it back together.
1. See the photo of the pump side where I show there are 3 gaskets, doesn't seem right to me. Shouldn't there
just be one thick gasket and one thin gasket?

2. See photo of other side with spring, needle and lever. I found I could not press down on the lever at all, thus the needle was not pushed up by the spring.

I would enjoy a quick reply by anyone.
thanks,
Greg

ggratecc · Oct 28, 2019

All,
One more question... See photo

See the little loose piece that goes in the long oval hole...
it looks like a little spoon.. wondering which way you install this, is
it with the depressed/rounded part DOWn or UP?
TIA,
Greg

MAC 3200 will not start

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