Honda bf 2.3 fuel leak from carb

[Crinan12]

Hi. I wondered if anyone can help me fix the fuel leak from the carburetor of my honda 4 stroke 2.3hp.

I posted about it previously and was told it was likely to be a problem with the float valve.

I've stripped it down and reinstalled the carb a few times in the hope it will stop leaking but it hasn't and I don't really know what else to do - but I'm not really sure what I'm looking for.

Does the float/needle look okay? Is there anything I can adjust? Would buying a new float assembly be sensible?

Or could it just be the round rubber gasket between the bowl/carburetor that needs replaced?

Any advice appreciated

Thanks

 

[chriscallender]

A quick and dirty test you can do with the carb off and the bowl empty - blow into the carb fuel intake, the float should be letting air through. Then turn the carb upside down and see if you can still blow. If you can, the float valve isn't sealing. That's not a completely definitive test that all is well however it gives an indication. As well as that, another thing you can sometimes do is attach a piece of clear tube to the drain on the bowl and see what level it fills to.

It looks fairly alright to me in the photos but its hard to tell. Remember also that a bit of dirt in the valve seat (which isn't very clear in any photo) could just as easily stop it sealing.

Chris

 

[Crinan12]

Thanks chris - test complete - I can't blow any air through when turned upside down.

 

[chriscallender]

Thanks chris - test complete - I can't blow any air through when turned upside down.

Ok... a bit of a mystery then. If its still that area, possibly a float that doesn't actually float, or it/the valve is sticky/catching on something. Otherwise just about the only other way I can think of a carb leak is if the drain screw/washer leaked... which would be pretty obvious.

 

[Crinan12]

I just tried it again in the hope that the blowing thing you suggested might have helped

But fuel just pours out from the join between the bowl and the carburetor (indicated in photo)

Actually tempted to just buy a new carburetor!

 

[chriscallender]

I just tried it again in the hope that the blowing thing you suggested might have helped

But fuel just pours out from the join between the bowl and the carburetor (indicated in photo)

Actually tempted to just buy a new carburetor!

One I took apart a few weeks ago (different model/engine) had a rubber O ring there. I don't think its meant to fill up that full anyway, presumably the O ring is just to deal with the fuel sloshing about on waves etc. As far as I know they are designed to leak from somewhere though, if the float doesn't work, so that the liquid fuel doesn't go into the cylinder (or crankcase in the case of a 2 stroke). And they also need to be vented somehow anyway so that the pressure in the float chamber is at atmospheric pressure.

With 2 stroke strimmers I've quite often resorted to new carbs to make them go, they are cheaper than the time spent cleaning the old ones would be worth. So if it isn't much money that might be the way to go.

For my boat outboard I cleaned it and then the engine ran fine (the float stuff was OK with mine, there was a bit of something in the main jet which I could see with a torch, and the engine would only run with the choke on). I bought a 2nd hand "spare" carb anyway so that I could just do a quick swap if I had a problem again in future. Gave the spare a good clean out and at some point I'll test it on the engine.

 

[Crinan12]

Whatever I have now done has made it worse, fuel would just drip before but now it pours out quite quickly

I did wonder about the oring but as you say maybe doesn't fill that far up anyway

A new after market carb is only about £40. No idea what they are like but might give one a go. Maybe I can even just use the float and needle out of it to see if that's the problem with mine.

My float moves about freely and seems to pass the blow test you suggested but maybe I did something to it when I took it apart.

 

[DanTribe]

I have the same problem with mine. Considering Honda's reputation for quality engineering, very disapointed with the build quality of these engines.
I had a problem with the carburettor on my Briggs & Stratton lawn tractor a couple of years ago. Cleaned & cleaned and soaked in carb cleaner overnight several times. Eventually bought a Chinese replica carb for less than a pukka overhaul kit. Instant fix!. No qualms about quality of replicas.

 

[rowlock]

From your description the joint between the body and bowl appears to be the source of the leak. With the centre fixing screw removed check there is a small (0.5mm) gap between the inner face of the bowl and fixing post when the bowl is firmly pressed against the seal. Previous over tightening may deform the bowl base reducing clamping pressure. Be sure to check the mating surfaces are scrupulously clean and the bowl face is free from rust pitting which can be a source of leaks. If so a temporary fix is to reface the bowl with sand paper on a flat surface. Replace the seal, they can easily become deformed. Annoyingly it is a D section O ring of odd size so Honda kit 16010-zw6-611, which has has all the seals in the carburettor is the hassle free option. Aprox. £17 delivered from Ebay sellers. Possibly less from your local Honda dealer if you can collect. With care they can last years.
New bowls are a wicked and eye watering £50+ from Honda for this engine. A measure of Honda is that bowls for the larger and common GX engines are available for a fiver delivered. For some reason Honda bowls corrode in no time and the corrosion appears to be the source of blocked galleries and metering jets, the curse of this outboard. Making and fitting an aluminium bowl shows promising results to remedy this.
Regarding replacement in practice not all component parts fitted to some aftermarket offerings have been found to be identical to the original parts fitted to the original carburettors.
Also experience has shown while aftermarket carburettors work they can be difficult to set up to run smoothly and at consistent RPM at tickover consequently the centrifugal clutch can engage at inconvenient moments in service.
While frustrating, servicing an original fit carburettor is the least bad of the worst solutions.

 

[Crinan12]

From your description the joint between the body and bowl appears to be the source of the leak. With the centre fixing screw removed check there is a small (0.5mm) gap between the inner face of the bowl and fixing post when the bowl is firmly pressed against the seal. Previous over tightening may deform the bowl base reducing clamping pressure. Be sure to check the mating surfaces are scrupulously clean and the bowl face is free from rust pitting which can be a source of leaks. If so a temporary fix is to reface the bowl with sand paper on a flat surface. Replace the seal, they can easily become deformed. Annoyingly it is a D section O ring of odd size so Honda kit 16010-zw6-611, which has has all the seals in the carburettor is the hassle free option. Aprox. £17 delivered from Ebay sellers. Possibly less from your local Honda dealer if you can collect. With care they can last years.
New bowls are a wicked and eye watering £50+ from Honda for this engine. A measure of Honda is that bowls for the larger and common GX engines are available for a fiver delivered. For some reason Honda bowls corrode in no time and the corrosion appears to be the source of blocked galleries and metering jets, the curse of this outboard. Making and fitting an aluminium bowl shows promising results to remedy this.
Regarding replacement in practice not all component parts fitted to some aftermarket offerings have been found to be identical to the original parts fitted to the original carburettors.
Also experience has shown while aftermarket carburettors work they can be difficult to set up to run smoothly and at consistent RPM at tickover consequently the centrifugal clutch can engage at inconvenient moments in service.
While frustrating, servicing an original fit carburettor is the least bad of the worst solutions.

Thanks that's v useful

I checked and the inner face of the bowl is tight against the post so perhaps I did over tighten it
I'll order a new bowl and gasket and hopefully that will solve the problem.

 

[jamie N]

As an aside concerning the corrosion of the bowl, I've not had this issue after 13 years. I'll suggest that it's because I give the motor a good coat of WD40ing a couple of times a year, and a wipe down with a rag, plus I drain the carb every day that the motor's used, which I believe is a most crucial part of long term servicability and reliability of these engines.

 

[Alex_Blackwood]

A quick and dirty test you can do with the carb off and the bowl empty - blow into the carb fuel intake, the float should be letting air through. Then turn the carb upside down and see if you can still blow. If you can, the float valve isn't sealing. That's not a completely definitive test that all is well however it gives an indication. As well as that, another thing you can sometimes do is attach a piece of clear tube to the drain on the bowl and see what level it fills to.

It looks fairly alright to me in the photos but its hard to tell. Remember also that a bit of dirt in the valve seat (which isn't very clear in any photo) could just as easily stop it sealing.

Chris

That "O" ring in 114907 looks damaged. Top left sector? I would replace that irrespective.