Backfire

[Dan.gerous 2,696]

Had problems getting my C125 to run, so replaced the fuel lines as it only ran for about three seconds then died.

 

Now it runs fine for as long as you like, but only with full choke on. If you try and decrease choke and increase throttle it dies, or starts back firing like mad.

 

It's a handy bird scarer but not much use as you can't really drive it anywhere.

 

Help!!!

Edited April 19, 2020 by Dan.gerous

[squonk 41,020]

Fuel pump and or carb needs cleaning

[Dan.gerous 2,696]

9 minutes ago, squonk said:

Fuel pump and or carb needs cleaning

Ah ok, easy to do I guess?

 

Will have to set aside some time as really need it working.

[peter lena 8,580]

dan.gerous, in addition to the fuel pump and carb work , using  seafoam  gas treatment REGULARLY  will help insure a better running unit, https://seafoamsales.com/ . this is my own experience , and since staying after a ( used to be problem) area , i have no fuel issues , good luck with it .pete

[ZXT 2,401]

38 minutes ago, Dan.gerous said:

Ah ok, easy to do I guess?

 

Will have to set aside some time as really need it working.

Yes, very easy. Pull the carb off, pull the bowl off, remove float and needle, pull all of the adjustment screws, and spray out every passage you see with carburetor cleaner. 

 

No need for a kit unless you tear the bowl seal which is unlikely. 30 minutes and less than half a can of carburetor cleaner and you ought to be up and running. 

 

On the adjustment screws, turn them clockwise until they seat lightly while counting the turns and write it down. Turn them back out the same amount when you reassemble and you should only have to fine tune it by ear from there. When turning them in, do not tighten them much or you will damage the needles! Just until they stop turning easily.

Edited April 19, 2020 by ZXT

[ZXT 2,401]

1 minute ago, peter lena said:

dan.gerous, in addition to the fuel pump and carb work , using  seafoam  gas treatment REGULARLY  will help insure a better running unit, https://seafoamsales.com/ . this is my own experience , and since staying after a ( used to be problem) area , i have no fuel issues , good luck with it .pete

That and run ethanol free fuel!

[Dan.gerous 2,696]

Awesome everyone, will tackle that in a few minutes and see how I get on. I don't have any carb cleaner so guess just using petrol will have to do the job for now until I can get some ordered.

 

Thanks again, you guys are the best

[ZXT 2,401]

1 minute ago, Dan.gerous said:

Awesome everyone, will tackle that in a few minutes and see how I get on. I don't have any carb cleaner so guess just using petrol will have to do the job for now until I can get some ordered.

 

Thanks again, you guys are the best

Carb cleaner, brake parts cleaner, just about anything will work. Gasoline will work fine to wash the bowl out with. I've used compressed air to blow the passages out when I was out of carb cleaner before and it worked fine. 

[Pullstart 62,784]

If you have any torch tip or pipe cleaners to run through the passages it’ll help too!

[ZXT 2,401]

Just now, pullstart said:

torch tip cleaners to run through the passages it’ll help too!

 

For less than $2 on eBay, there's no reason not to keep a couple of sets around.

[oliver2-44 9,679]

Look closely at the long needle and you wil see holes crosswise through it. Those are the passages that need cleaned out, but be careful to not team them larger. A wire off a wire brush held in a vice grip works if you don’t have a tip cleaner. 

[lynnmor 7,302]

Do not use wire cleaners as they will scratch the bore of the various jets causing more or less fuel flow.  Use a bristle from a paint brush and carburetor cleaner.  A spray can of cleaner makes a good substitute for compressed air, just be sure to protect your eyes.

[gwest_ca-(File Mod) 11,032]

Before you dig too deep do you have another condenser you can try? They can fail in a way one would swear the problem is fuel related.

 

Garry

[wfrpalm 218]

I vote for a carb clean and SeaFoam every once in a while

[Dan.gerous 2,696]

Evening all, just an update.

 

Got the carb off and cleaned with petrol, then blew through with compressed air. Everything seemed nice and clean, could see through all the holes etc.

 

Once I got the pump primed it started no problem, and ran without the choke. Still running a bit rough with the occasional backfire, and won't idle but that's hopefully just a case of a bit of tuning.

 

Have a new condenser on it, but if I can't get it to run cleanly then that will be the next option.

 

At least it's 100% better than before and actually useable now thanks to all the advice.

 

I also noticed the tip of the needle was slightly bent, as if it had been wound in to far at some point - or is it supposed to be like that?

 

[Dan.gerous 2,696]

2 hours ago, gwest_ca said:

Before you dig too deep do you have another condenser you can try? They can fail in a way one would swear the problem is fuel related.

 

Garry

I actually just brought another wheelhorse so can try the condenser off that one when I get it home.

[Dan.gerous 2,696]

49 minutes ago, wfrpalm said:

I vote for a carb clean and SeaFoam every once in a while

Will have to look up the sea foam option and see if we can get that in the UK or is equivalent.

[lynnmor 7,302]

2 hours ago, Dan.gerous said:

 

I also noticed the tip of the needle was slightly bent, as if it had been wound in to far at some point - or is it supposed to be like that?

 

 

No needle is supposed to be bent, perhaps the bent needle also damaged the carb body,  Can you post a photo?

[Tuneup 1,433]

Need to test condensor so buy tractor - got it but it's too late for me. I needed plugs but didn't know I only had to buy another Wheel Horse to get them! Nice job! 

[ZXT 2,401]

7 hours ago, Dan.gerous said:

Got the carb off and cleaned with petrol, then blew through with compressed air. Everything seemed nice and clean, could see through all the holes etc.

 

Once I got the pump primed it started no problem, and ran without the choke. Still running a bit rough with the occasional backfire, and won't idle but that's hopefully just a case of a bit of tuning.

I also noticed the tip of the needle was slightly bent, as if it had been wound in to far at some point - or is it supposed to be like that?

 

 

Glad it is running better! Did you take the jet out of the carb or leave it in? Sometimes debris can get caught in it. I failed to mention pulling it out before. I apologize if that's the issue.

 

The needle should most definitely not be bent. Being bent, it's possible that it damaged the main jet in the carburetor which could also cause issues.

 

Not sure why any of this would cause it to backfire, though, unless it is lean and just needs adjusting. Condensers are cheap enough to try and could definitely cause a backfire.

 

Are we going to see a thread on your new Horse?

[Dan.gerous 2,696]

7 hours ago, lynnmor said:

No needle is supposed to be bent, perhaps the bent needle also damaged the carb body,  Can you post a photo?

Will get it appart again today and post a picture, it was just the very tip sightly bent over.

[Dan.gerous 2,696]

6 hours ago, Tuneup said:

Need to test condensor so buy tractor - got it but it's too late for me. I needed plugs but didn't know I only had to buy another Wheel Horse to get them! Nice job! 

I know I'm a genius! 😁

[Dan.gerous 2,696]

1 hour ago, ZXT said:

Glad it is running better! Did you take the jet out of the carb or leave it in? Sometimes debris can get caught in it. I failed to mention pulling it out before. I apologize if that's the issue.

 

The needle should most definitely not be bent. Being bent, it's possible that it damaged the main jet in the carburetor which could also cause issues.

 

Not sure why any of this would cause it to backfire, though, unless it is lean and just needs adjusting. Condensers are cheap enough to try and could definitely cause a backfire.

 

Are we going to see a thread on your new Horse?

Will have a play around and see if I can tune the backfire out, otherwise order a new condenser. Just a case of trial and error hopefully. Will post a picture of the needle later.

 

Have a new thread on my new horse, just need to upgrade account so I can post more pictures 🙂

[Dan.gerous 2,696]

Is the condenser a generic thing I can just order new anywhere?

[Dan.gerous 2,696]

Ok, took the needle out and cleaned up the burred over end. Put it back in and after playing about with the settings she runs as sweet as a nut. It even idles which it wasn't doing before and so far there hasn't been a backfire. Just about to go on a test run and see if I can make it misbehave....

Edited April 20, 2020 by Dan.gerous