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Fuel problem with Zama Carb/Poulan leaf blower


OverRHeads's Avatar
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09-27-09, 10:12 AM   #1  
Fuel problem with Zama Carb/Poulan leaf blower

I have a Poulan leaf blower with a Zama C1Q carb and have been having trouble lately. It has become very hard to start.

The instructions say to prime the bulb 8 times, flip choke lever to full choke and pull starter until it tries to start. This has always worked but now when I try this method it will not start. I smell fuel so I pull the plug and it is flooded and soaking wet. I ordered and installed a new carb kit (new gaskets, diaphrams, needle, spring, and primer bulb). However I am still having an issue.

I pulled the carb while still attached to the fuel pickup and return lines and pressed the primer bulb and there is a substantial amount (6-8 large drops) of fuel coming out of the carb venturi. I am pretty sure this is not how this is supposed to work. Isn't the primer bulb simply there to get fuel from the tank to the carb? It is not supposed to be "injecting" fuel into the cylinder is it?

Any help would be appreciated!

 
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09-27-09, 11:09 AM   #2  
the primer sucks the gas from the fuel pickup in to the carb and back to the tank a little fuel will shoot in to the carb body to help start it try not pumping th primer so many pumps and only choke 1/2 and see what happens

 
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09-27-09, 11:31 AM   #3  
Thanks for the suggestion. I have tried that and it DID help but still did not solve the problem. I can get it going using this method but I have to pull 10-15 times very rapidly to get it to fire. My wife uses the the blower often but she is unable to repeatedly pull the starter cord. The thing that gets me is that it used to start with only three pulls: one with or two with full choke and then flip to half choke and it would start.

I have the carb soaking in carb cleaner right now to see if I can loosen and break free something in the carb. The one thing I did not do with the carb kit is replace the welch plugs. It appears from the parts that came in the carb kit that there is another needle under one of the welch plugs as there was an extra needle in the kit. I do not have the tools to replace the welch plugs. Can I use another "common" tool to drive the plugs in?

Thanks!

 
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09-27-09, 11:32 AM   #4  
Did you set the metering lever correctly?

ZAMA has a free sevice manual and service tips on their website.

USA Zama : Service Tips

 
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09-27-09, 11:50 AM   #5  
I would not take the welch plugs out.Check this,take the muffler off and take your hand or thumb and see if the head has come loose from the crankahaft.If so you have a air leak,and you will have to disassemble the whole blower and retighten the head bolts.I have found a lot of blowers with this problem.Hope this helps.

Jerry

 
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09-27-09, 11:50 AM   #6  
Airman: I will check that when I reassemble it in a few minutes. Would this cause excessive amounts of fuel to come out of the tiny idle pinholes in the venturi when priming the engine?

JSouth: I have checked the tightness of the bolts holding the head on and they are tight. It runs great once it is running. The issue I am having is a priming and starting issue in the carb.

 
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09-27-09, 01:27 PM   #7  
I would think excessive fuel could only happen when the primer is pushed too much.

Fuel should come out of the circuit ports/holes when you depress the primer.

Behind the model number of on you carburetor are some other numbers/letters. What are they?

An improperly set metering valve can result in hard starting, rich idle, poor acceleration, rich engine, flooding or low power at wide-open throttle.

The manual states, “To prevent air from entering the metering chamber during primer operation there is a one-way check valve in the idle circuit and main nozzle. Every time the primer bulb is depressed this process is repeated causing any old fuel or air that was in the carburetor to be displaced by fresh fuel from the tank. The fresh fuel in the carburetor makes the engine easier to start.

Note that once the metering chamber has been filled with fresh fuel continuing to push on the primer bulb will not help improve the starting of the engine.”


I just saw your second post at 2:31 PM when I was making this post. Soaking a carburetor of this type is a no-no. The check valves could have been damaged. Rarely does this type carburetor need much cleaning and then an aerosol carburetor cleaner should be used.

If you will download the Zama Technical Guide and review it will benefit you.

The manual states, “Note: It is often un-necessary to remove the welch plug. Test for plugged progression holes by spraying carb cleaner into the L needle hole. If cleaner sprays out the progression holes there is no need to remove the welch plug.”

It may not have been damaged when it was soaked so just treat it as it hasn’t.

 
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09-27-09, 02:19 PM   #8  
Posted By: Airman I would think excessive fuel could only happen when the primer is pushed too much.

Fuel should come out of the circuit ports/holes when you depress the primer.

Behind the model number of on you carburetor are some other numbers/letters. What are they?

An improperly set metering valve can result in hard starting, rich idle, poor acceleration, rich engine, flooding or low power at wide-open throttle.

The manual states, “To prevent air from entering the metering chamber during primer operation there is a one-way check valve in the idle circuit and main nozzle. Every time the primer bulb is depressed this process is repeated causing any old fuel or air that was in the carburetor to be displaced by fresh fuel from the tank. The fresh fuel in the carburetor makes the engine easier to start.

Note that once the metering chamber has been filled with fresh fuel continuing to push on the primer bulb will not help improve the starting of the engine.”


I just saw your second post at 2:31 PM when I was making this post. Soaking a carburetor of this type is a no-no. The check valves could have been damaged. Rarely does this type carburetor need much cleaning and then an aerosol carburetor cleaner should be used.

If you will download the Zama Technical Guide and review it will benefit you.

The manual states, “Note: It is often un-necessary to remove the welch plug. Test for plugged progression holes by spraying carb cleaner into the L needle hole. If cleaner sprays out the progression holes there is no need to remove the welch plug.”

It may not have been damaged when it was soaked so just treat it as it hasn’t.
I downloaded the guide from their website a few days ago and saved it to my computer.

The excessive fuel is coming out after only 2-3 primes and the instructions say to do it 8 (which is how many I used to do when it was working correctly) so I would not think I am priming it too much. Would you?

I set the metering valve a few minutes ago and after reassembly it was still flooding.

I soaked it for a few minutes in an old soup can containing the overspray from the aerosol carb cleaner I had been spraying in the holes of the carb. Do you think this damaged anything?

Finally, this carb is designed so that the consumer cannot remove or adjust the "L" or "H" needle adjustments. They are not screws. They are round black heads that appear to be serrated for gripping with a special tool. They are also recessed so reaching them with a pair of needlenose pliers is also out of the question. Therefore, spraying through the "L" hole is not possible.

Also, the carb is a C1Q W11D 42A



Last edited by OverRHeads; 09-27-09 at 02:44 PM.
 
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09-27-09, 02:53 PM   #9  
My suggestions;
Replace the fuel lines, if you replaced the metering arm when you installed the new kit re-install the old one unless it was very worn, as it has the proper height setting, blow through all holes with brake parts cleaner. When you get it restarted, while it is running spray carb/brake cleaner along all mating surfaces behind the carb and along the crankcase, if the engine tempo changes you have an air leak and can take appropriate action. Have a good one. Geo

 
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09-27-09, 02:58 PM   #10  
Posted By: geogrubb My suggestions;
Replace the fuel lines, if you replaced the metering arm when you installed the new kit re-install the old one unless it was very worn, as it has the proper height setting, blow through all holes with brake parts cleaner. When you get it restarted, while it is running spray carb/brake cleaner along all mating surfaces behind the carb and along the crankcase, if the engine tempo changes you have an air leak and can take appropriate action. Have a good one. Geo
Thanks for the input! I think replacing the fuel lines is where I am going next but I will try the air leak test.

Thanks again!

 
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09-27-09, 07:14 PM   #11  
I do not want anyone to think that I advocate disobeying EPA rulings, sometimes a little tweat will keet the whole item out of a landfill.
The tool you need is only available to dealers or service centers, sometimes you can buy them on ebay, however, as with everything, need breeds invention or make do, below is a picture of a make do, you have to force it onto the screw. Have a good one. Geo

 
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09-27-09, 07:38 PM   #12  
Posted By: OverRHeads I downloaded the guide from their website a few days ago and saved it to my computer.

The excessive fuel is coming out after only 2-3 primes and the instructions say to do it 8 (which is how many I used to do when it was working correctly) so I would not think I am priming it too much. Would you?

I set the metering valve a few minutes ago and after reassembly it was still flooding.

I soaked it for a few minutes in an old soup can containing the overspray from the aerosol carb cleaner I had been spraying in the holes of the carb. Do you think this damaged anything?

Finally, this carb is designed so that the consumer cannot remove or adjust the "L" or "H" needle adjustments. They are not screws. They are round black heads that appear to be serrated for gripping with a special tool. They are also recessed so reaching them with a pair of needlenose pliers is also out of the question. Therefore, spraying through the "L" hole is not possible.

Also, the carb is a C1Q W11D 42A

what 'i'did was use a piece of 1/4 " steel brake tubing-after-it cut with a tubing cutter-use an ice pic type pic to slightly enlarge the tubing-untill it will serve as a 'tool 'to remove the mixture screws(one-at a time)-'carefuly'mount screws-head side up in a vice-use a 'fine'tooth hack saw blade-make a screw driver slot in the head of each mixture screw.
!! first-i use a 'depth michrometer'-to measure the inital setting of the screws-usualy about 0.090"
are you sure you have the correct kit?
'i' have found that the 'zama-rb-115'kit is what these little carbs use.

 
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09-27-09, 08:46 PM   #13  
This may sound kinda silly,, but when you put the carb together,, you have carb,, than gasket,, than meetering diaghragm, Right??? Cus if the gasket is on the wrong side of the diaghragm it'll work like you describe,,, Just ask me how I know,, LOL.... Roger

 
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09-28-09, 10:04 AM   #14  
Posted By: hopkinsr2 This may sound kinda silly,, but when you put the carb together,, you have carb,, than gasket,, than meetering diaghragm, Right??? Cus if the gasket is on the wrong side of the diaghragm it'll work like you describe,,, Just ask me how I know,, LOL.... Roger
I have done the same thing before on a pulse fuel pump on an outboard motor. I did reassemble this one correct per the diagram on Zama's website! Thanks for the suggestion though!

 
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07-05-12, 03:51 PM   #15  
question

I have a similar problem and I apologize for barging into this thread but I was hoping maybe I could get an answer. I have the poulan wt200 leaf blower and on ours the primer bulb will not pop back out when depressed. So I cannot prime it but once thus it will not start. Do I need a whole carburetor kit to fix it or is there a filter or something that I can replace? Sincere thanks in advance.

Flux

 
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07-05-12, 09:44 PM   #16  
You'll need to clean the carb... the screen is probably clogged.


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God bless!

 
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07-06-12, 09:04 PM   #17  
To Fluxblocker You may have a diaphragm stuck or the fuel pump diaphragm is stuck. Yes a kit is a good advice from me. Been there done that!

 
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