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Zama C1Q-EL7 issue

Huskyvarnya Saws

Huskyvarnya Saws

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Jan 1, 2021
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Alabama
I recently rebuilt a Husky 55 with a Zama C1Q-EL7 carb. I did some looking around on the forums and saw where people were saying 1-1/4 turns out on the high and low was a good starting point. I followed that advice, but after a fair amount of adjusting I just can't seem to get it to run right. There seem to be a couple of issues going on. The fist one is that even at almost 1-1/2 turns out the saw still isn't 4 stroking at all. The second issue is on the low side. At a shade over 1 turn out the saw will die at idle as if it's running too rich. The idle isn't erratic or anything like that it just dies after a few seconds. The carb has new gaskets/diaphragms and passes a pressure test at 7 psi. I have only rebuilt a hand full of saws, and admittedly carburetors and tuning are not my strong suit at this stage. I have never "dug deep" into a carburetor, or done anything past replacing diaphragms/gaskets, needle, lever, and spring. Could a partially clogged passage be causing the issue with the high jet? Could there possibly be something going on that removing the welch plug could reveal? Any advice would be greatly appreciated.
 
Stateline Sawer

Stateline Sawer

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So hard to say what's going on. How's the intake boot look? The impulse grommet? Carb installed nice and tight, (but not to tight as you are screwing into plastic). I always spray brake cleaner into all the little orifices of the carb, including removing needles and hosing them down. Remove the welch plugs, might as well go buy a Chinese clone carb from Amazon...
 
Huskyvarnya Saws

Huskyvarnya Saws

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71
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Alabama
So hard to say what's going on. How's the intake boot look? The impulse grommet? Carb installed nice and tight, (but not to tight as you are screwing into plastic). I always spray brake cleaner into all the little orifices of the carb, including removing needles and hosing them down. Remove the welch plugs, might as well go buy a Chinese clone carb from Amazon...
Intake and impulse are both brand new and pressure tested. I installed helicoils in the bulkhead along with new M5 Bolts with washers to avoid the plastic thread issue down the road. I made a new gasket as well and everything is nice and tight. I am fairly certain that the problem lies within the carb, but I will check everything again tomorrow to be 100%.
 
Vintage Engine Repairs

Vintage Engine Repairs

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I’d suggest uploading a video here of you setting the carb to 1&1 with new fuel filter, clean air filter and ensure the muffler screen isn’t blocked.

Increase the idle screw so it holds idle then blip the throttle so we can hear the saw clearly, also run it at WOT for a few seconds a few times allowing it to return to idle.

I wonder if what you think you’re hearing isn’t actually what’s going on.

Go through the correct starting procedure. Even if the saw doesn’t start, upload the video.

From there we can go in a methodical direction from A to B rather than run around in circles chasing our tails.
 
cookies

cookies

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i have experienced issues with zama's internal check valves that test good when apart but when on a running engine fail, I have had zamas be unable to deliver enough fuel using the hard plastic fuel pump diaphragms but swapping to the soft butyl version it pumps plenty...I now refuse to ultrasonic clean, spray directly with carb or compressed air on zamas.
 
Huskyvarnya Saws

Huskyvarnya Saws

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Alabama
I appreciate the replies fellas. I had a busy day so I didn't get around to doing the video. I'll try to get that posted tomorrow, and maybe that will give some clues as to what is going on.
 
Huskyvarnya Saws

Huskyvarnya Saws

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Alabama
I finally got around to shooting a couple of videos this evening. I ran the saw earlier in the day really rich for a little protection prior to shooting the video. That's why there is so much smoke. I checked the plug prior to the test as well and it was black/wet. After the test I checked it again and took a pic. It was probably a shade lighter than it looks in the picture. So I would think that at 1 1/4 turns out it is indeed running lean to lighten it up that much during the test. If i'm way off on that please correct me.

0331211905b.jpg
 
Vintage Engine Repairs

Vintage Engine Repairs

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L
I finally got around to shooting a couple of videos this evening. I ran the saw earlier in the day really rich for a little protection prior to shooting the video. That's why there is so much smoke. I checked the plug prior to the test as well and it was black/wet. After the test I checked it again and took a pic. It was probably a shade lighter than it looks in the picture. So I would think that at 1 1/4 turns out it is indeed running lean to lighten it up that much during the test. If i'm way off on that please correct me.

View attachment 898521
Great, looking forward to seeing the videos.
 
Huskyvarnya Saws

Huskyvarnya Saws

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L

Great, looking forward to seeing the videos.
Forgive the poor video recording skills. The sound probably could have been better outside, but the weather was not so great, and I couldn't find a decent place to set my phone up to record.
After I shot the video, before reinstalling the fuel filter, I did pressure/vac test the fuel line.
The saw died on it's own at the end, just to clarify.

 
Vintage Engine Repairs

Vintage Engine Repairs

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Firstly, well done for the video, it was filmed well.

From what I can hear, and note that it’s quite tinny -(better to be outside with the muffler pointing to the camera a few meters away), your off idle acceleration sounds good, your butterfly (idle screw) is a touch too open, close it a little as the chain is creeping.
Return to idle is smooth and not stepping down and starts nicely cold. All good signs the L screw is in a fairly good place.

WOT is hard to hear, but it is safer to be richer than leaner, and from that angle I can’t quite hear 4 stroking. Just tweak it another 1/8 of a turn to be safe.

All in all, your saw sounds ok, another video outside with the muffler facing the camera and a few meters away would be good to confirm H screw.

If your saw dies soon after starting or after WOT firstly repeat it again without the tank vent on the fuel tank. If that makes no difference, double check your metering lever height. If it’s too low, it won’t let enough fuel into the metering side.

Once you’ve confirmed the above two things aren’t the issue try the following.

Get the saw nice and warm (maybe take that next video at the same time) and as soon as it dies, quickly remove the spark plug, press it back into the boot (don’t burn yourself!), place the plug on anything metal on the saw and pull it over. You’re looking for a bright blue spark.
 
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