19 replies to this topic

[Dfitzy]

I'm having a problem getting my carb to maintain its mixture for more than a couple of days.

 

After removing and cleaning the carb, then tuning it for a correct mixture, it runs great for a day or two until it gradually becomes too rich to run properly. I eventually have to start backing the mixture screw out over time until it's all the way out. I've ruled out ignition or any other items that would cause it to continually run poorly. Again, it resets after I take the carb off and drain it, and then slowly gets worse over a few days.

 

So far I've replace the float, needle, needle and seat, and dashpot oil, and made sure the piston moves smoothely. Any ideas on what could cause it to enrich over a few days?

Edited by Dfitzy, 25 June 2017 - 09:17 PM.

[nicklouse]

wrong oil in the dash pot.

 

are you actually looking at the jet position each time?

 

is it actually different.

[Dfitzy]

wrong oil in the dash pot.

 

are you actually looking at the jet position each time?

 

is it actually different.

I'm using 20/50 oil, and I've been checking the jet position. The jet isn't moving between adjustments. It comes so rich that even raising it to above the bridge doesn't help. Obviously I don't set it that way at the beginning.

 

edit: 0-20 oil

Edited by Dfitzy, 25 June 2017 - 09:32 PM.

[Dfitzy]

 

wrong oil in the dash pot.

 

are you actually looking at the jet position each time?

 

is it actually different.

I'm using 20/50 oil, and I've been checking the jet position. It comes so rich that even raising it to above the bridge doesn't help. Obviously I don't set it that way at the beginning

 

Pardon me, 0-20 oil.

[mk1leg]

have you removed the adjustment screw when cleaning

Edited by mk1leg, 25 June 2017 - 09:44 PM.

[Dfitzy]

have you removed the adjustment screw when cleaning

No I haven't done that

[nicklouse]

 

 

wrong oil in the dash pot.

 

are you actually looking at the jet position each time?

 

is it actually different.

I'm using 20/50 oil, and I've been checking the jet position. It comes so rich that even raising it to above the bridge doesn't help. Obviously I don't set it that way at the beginning

 

Pardon me, 0-20 oil.

 

then try some 20-50  as the only thing that can be happening is your needle is lifting too fast.

[Dfitzy]

 

 

Pardon me, 0-20 oil.

 

 

then try some 20-50  as the only thing that can be happening is your needle is lifting too fast.

 

I could see that under load for sure, but it's incredibly rich at idle too once it starts acting up. It eventually doesn't idle at all.

[nicklouse]

ok then what about the spring? is it correct?

 

correct spring, 20-50 oil and never had any issues. (check oil every so often)

[Dusky]

Maybe the bimetal failing in an odd way?

[blacktulip]

Is the choke shutting off properly?

[Dfitzy]

Is the choke shutting off properly?

Thats what im wondering. The choke returns properly on the outside of the carb. Could there be something sticking with the mechanism inside? Or a seal gone bad? The gradual nature of it is what's stumping me.

[minimans]

 

 

 

wrong oil in the dash pot.

 

are you actually looking at the jet position each time?

 

is it actually different.

I'm using 20/50 oil, and I've been checking the jet position. It comes so rich that even raising it to above the bridge doesn't help. Obviously I don't set it that way at the beginning

 

Pardon me, 0-20 oil.

 

then try some 20-50  as the only thing that can be happening is your needle is lifting too fast.

 

If the needle/piston is lifting too fast it would be lean not rich.

[Pigeonto]

As Blacktulip. Close inspection of the choke assembly and renew the 2 O rings ( not the same as each other) and outer seal. Not sure they will allow fuel into venturi if leaking but they'll allow fuel to leak out wards eventually so well worth doing. 

[Dfitzy]

As Blacktulip. Close inspection of the choke assembly and renew the 2 O rings ( not the same as each other) and outer seal. Not sure they will allow fuel into venturi if leaking but they'll allow fuel to leak out wards eventually so well worth doing. 

Thanks, I'll try and track down the gasket kit today.