Stihl BG75 blower carb diagram

[mercracing]

Does anyone have or know where I can download a blowup of the carb for one of these blowers? Mines not running well. Thanks for the help!


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[ricleh]

Which carburetor do you have? Stihl parts list shows 3. Zama C1Q-S47, C1Q-S30C or Walbro WT-413. You are probably better off getting a new carb than trying to rebuild yours. You can get technical info for the Zama carbs at www.zamacarb.com. Exploded picture of the Walbro carb is available at wem.walbro.com/walbro.

 

[mercracing]

Many thanks!


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[shawhite]

I would just replace the carb they usually run like $30 at my local Stihl dealer

 

[mercracing]

Yea I think replacing it might be the way to go. I'm hoping to have it up before any light snow flies and use it to clear the driveway and sidewalk.


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[morgaj1]

If it is one of the older carbs that still has the low and high speed adjustment needles, I would rebuild it. Most of the newer carbs are non-adjustable and tend to run lean to meet EPA requirements.

 

[mercracing]

I tried to rebuild it but it still runs like garbage. I looked on the Zama website to make sure I had everything the correct way, and I THINK I do so... Probably going to buy a carb

 

[mercracing]

Nope, new plan. I will humbly ask for help. I rebuilt the carb, replaced the primer bulb in tank fuel filter, and both fuel lines. I forgot which of the two hoses goes to which port so I have tried both. I can prime the bulb, not full but 80%. It will fire up and idle but when I give it throttle it bogs down and wants to die. If I prime the bulb when I have it at wide open throttle it runs like normal. Almost positive the carb is C1Q-S30C. Please be gentle with thoughts and ideas.

 

[morgaj1]

Nope, new plan. I will humbly ask for help. I rebuilt the carb, replaced the primer bulb in tank fuel filter, and both fuel lines. I forgot which of the two hoses goes to which port so I have tried both. I can prime the bulb, not full but 80%. It will fire up and idle but when I give it throttle it bogs down and wants to die. If I prime the bulb when I have it at wide open throttle it runs like normal. Almost positive the carb is C1Q-S30C. Please be gentle with thoughts and ideas.

The lower ****** should be the one connected to the fuel filter. The upper ****** should be your purge line. If you are able to run it only while priming it, you still have a blockage somewhere. Any chance that you know someone with an ultrasonic cleaner?

 

[mercracing]

The lower ****** should be the one connected to the fuel filter. The upper ****** should be your purge line. If you are able to run it only while priming it, you still have a blockage somewhere. Any chance that you know someone with an ultrasonic cleaner?

I will check. Some of my reloading buddies might. I still use a tumbler, but I can check with them to see if they can run it in there for me.

 

[stihlntime]

Do you have you diaphragms and gaskets in the right order, pump side gasket down first with diaphragm on top. On metering side diaphragm down first with gasket on top, did you change you needle? If the needle tip is red you should have replaced it.

 

[mercracing]

The diaphragms and gaskets should be correct. I checked on the zama website. Needle was changed with the carb kit.


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[djdaredevil]

This may sound stupid but did you clean the inside and the passages of the carburetor with carb cleaner or just put the new parts in?

 

[redmondjp]

This may sound stupid but did you clean the inside and the passages of the carburetor with carb cleaner or just put the new parts in?

I consider myself an expert on carbs (have been rebuilding them for, oh, about 40 years now), and even I have been completely stumped by more than one of these small-engine 2-cycle carbs. As I get older, my free time to spend 2-3 hours messing with a $40 carb (when the kit can be $25) isn't there any longer.

I spend five minutes getting the carb ID number (which can be hard to read), about 15 minutes online ordering a new carb (haven't seen one over $50 yet, most are $35-45, check Ebay and Amazon), and a few days later after it shows up in the mail, about another 15 minutes installing and adjusting it. Oh, how my life has been less frustrating now that I do this!

And then I recommend to the customer to use alcohol-free gas.

That's my $.02.

 

[mercracing]

This may sound stupid but did you clean the inside and the passages of the carburetor with carb cleaner or just put the new parts in?

Yea I tried to spray a little down each passage I saw. I didn't use the whole can but I used what I guessed to be an appropriate amount.


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[shawhite]

Did you clean the screen in your exhaust. Sometimes they get clogged and will only let the blower run at idle.

 

[mercracing]

Yup I took that off and heated it pretty good with a torch. Also cleaned spark plug.


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[djdaredevil]

I consider myself an expert on carbs (have been rebuilding them for, oh, about 40 years now), and even I have been completely stumped by more than one of these small-engine 2-cycle carbs. As I get older, my free time to spend 2-3 hours messing with a $40 carb (when the kit can be $25) isn't there any longer.

I spend five minutes getting the carb ID number (which can be hard to read), about 15 minutes online ordering a new carb (haven't seen one over $50 yet, most are $35-45, check Ebay and Amazon), and a few days later after it shows up in the mail, about another 15 minutes installing and adjusting it. Oh, how my life has been less frustrating now that I do this!

And then I recommend to the customer to use alcohol-free gas.

That's my $.02.

I guess I have good luck and have only had to replace 1 carb that was a Zama on an echo blower. (Now that I say that I wont have the good luck .)I take them apart and clean or replace parts spray every passage really well with cleaner and they are normally good to go if not than into the ultrasonic they go. Most kits can be had for less than $5 or $10
I dont like throwing things away and just buying new and most of my customers like saving the $30-$50 or more.

The ethanol free gas is a must .

Yup I took that off and heated it pretty good with a torch. Also cleaned spark plug.

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You could try and clean and adjust it again, or pick up an ultrasonic cleaner they are great to have. HF has cheap ones get the 2.5l not the smaller one. Check out DonyBoy73 and Bruce Penderon youtube they have videos on just about every small engine problem.
Now of course you could do all that and still have to replace the carb, but now you have an excuse to buy an ultrasonic cleaner.

 

[stihlntime]

Just for the heck of it I would visually inspect the cylinder and do a compression test. The BG 75 is getting long in the tooth. Should have a minimum of 100 psi too run, make sure the cylinder walls aren't scored.

 

[djdaredevil]

Just for the heck of it I would visually inspect the cylinder and do a compression test. The BG 75 is getting long in the tooth. Should have a minimum of 100 psi too run, make sure the cylinder walls aren't scored.

Also very good things to do. Im glad someone is thinking about something other than the carburetor.

 

[mercracing]

I'll do my best to inspect the cylinder. I did check compression, but I forget what it was so i'll check it again.


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[Scooterfish]

What is usually the problem when the blower will only run about 1/3 of the gas tank then die? When it starts to cut out if you turn it upside down it will run a few more minutes before dying. Refill tank and it starts right back up. Stihl BG 55. Sorry to cut in , Thanks for any help.

 

[redmondjp]

Also very good things to do. Im glad someone is thinking about something other than the carburetor.

Based upon your symptoms, also be sure to check the spark arrester screen inside the muffler - if clogged, that can allow the motor to idle but it will bog down and die at higher speeds.

 

[Provincial]

What is usually the problem when the blower will only run about 1/3 of the gas tank then die? When it starts to cut out if you turn it upside down it will run a few more minutes before dying. Refill tank and it starts right back up. Stihl BG 55. Sorry to cut in , Thanks for any help.

Check the fuel pick-up tube and screen in the tank. If the tube is cracked, it can **** air. If the screen isn't flopping to the bottom of the tank, it will end up above the fuel level as fuel is burned.

Also check the vent unit for the fuel tank. They can get sticky and not let air in to replace the burned fuel. Sometimes they can be cleaned with carburetor cleaner to free them up. Often, it is better just to replace the vent unit.

Report back on your progress!

 

[morgaj1]

Did you get it running?

 

[mercracing]

Short answer is no. I checked everything again and tried to fire it up. It runs just like before. I ended up taking it to my local dealer and said see what you can do for 50$ don't want to dump too much money in it. Looked at new units and they start at 130-140 I think so that's not bad. I'm trying to do a better job of prioritizing my time so I am spending more time with family. There are many things I probably can fix but my time is worth more. I would rather spend time with my wife and spend a few bucks to let someone else fix something then to do it myself. All within reason


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[DTE]

Did you clean the screen in your exhaust. Sometimes they get clogged and will only let the blower run at idle.

That is what was wrong with mine, it wouldn't rev. The way the muffler was built you could not take the screen out so I just drilled some holes in the muffler. That was 2 years ago. I have a 029 Farm boss saw that did the same thing but I was able to remove the screen on it.

 

[morgaj1]

Short answer is no. I checked everything again and tried to fire it up. It runs just like before. I ended up taking it to my local dealer and said see what you can do for 50$ don't want to dump too much money in it. Looked at new units and they start at 130-140 I think so that's not bad. I'm trying to do a better job of prioritizing my time so I am spending more time with family. There are many things I probably can fix but my time is worth more. I would rather spend time with my wife and spend a few bucks to let someone else fix something then to do it myself. All within reason


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No shame in that.

 

[justme-]

Future reference do not out these cards in ultrasonic cleaning units...they have internal check valves that can fail from the ultrasonic treatment. Zama and Walbro state not to use ultrasonic cleaners. It does sound like compression or restriction tho.

I've seen quite a few carbs over a hundred to replace, usually rotary style Husky and echo like.

Around here shop rates make rebuilding these little carbs impossible when a replacement is readily available, never mind the low success rate it a correctly functional unit from a rebuild.

 

[mercracing]

Thanks for the support and heads up guys!


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[Skin]

Around here shop rates make rebuilding these little carbs impossible when a replacement is readily available, never mind the low success rate it a correctly functional unit from a rebuild.

Servicing small 2-cycle equipment in general is cost prohibitive when you can often replace the unit for $200.

 

[mercracing]

Got a call from the service guy yesterday. The check valve(s) in the carb are bad. New carb ~100$. New blower ~140$ looks like Santa is going to need to grab a new blower for me.


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[WhiffySpark]

Make sure your spark arrestor screen isn't clogged. Very common

Nevermind... read the rest of the thread lol. Get a backpack they're worth it.

 

[djdaredevil]

Check online for a carb and slap in on real quick and youll be good to go. Save the money and keep the blower out of the landfill. I have a few carbs around Ill check if any are zama.

 

[404]

The two yellow dots I drew are right next to the check valves.. those little half round flaps on that gasket. Good luck what ever you choose to do.