cracked tube on johnson carb 150GT

[clevecan]

Heres a photo of the tube i'm talking about.
My boat started bogging when
throttleing up so rebuilt carbs and seen the lower carb has cracks in the
brass tube that has a smaller tube inside it.Has anyone had this happen
and if so what will it efect I think a lean condition, I could not get a great pic
so the tube behind the float is the worse one can kinda see it the crack runs
from bottom to top.theres holes for calabration and there cracked.I already
seen that a new carb ain't going to happen being none out there, so used
is the only way. Can these tubes be replaced?
thanks..

 

[Cofe]

Re: cracked tube on johnson carb 150GT

I have never heard of those tubes being replaceable. Being a weldor, I have silver soldered them with great success.

 

[clevecan]

Re: cracked tube on johnson carb 150GT

So your saying I can solder them, did you sorder the holes up and redrill them? or everywhere but near the holes.
Man this GT150 not many carbs out there to find a good one to use. thanks Cofe, being you say you have fixed
them before what problem did you incounter with the cracked emulsion tube? Mine is bogging and can push the key
in to prime the carbs and it hauls ace then but I have only ran it a little with the prob. No need to burn a piston.

 

[Cofe]

Re: cracked tube on johnson carb 150GT

I am a older professional weldor. Many years of practice with silver solder and thin materials. I suggest you find a qualified professional who can silver solder thin material. Those tubes are fragile, and no drilling is necessary if the soldering is done properly. If you cannot find a weldor who will attempt to solder them, take it to a Jeweler. I know they can silver solder precisely.

 

[clevecan]

Re: cracked tube on johnson carb 150GT

I'll see if I can find someone to repair it, thanks for the info. Has anyone ran across this emulsion tube crack prob?
Just wondering what the damaged tubes make the motor do. Mine has a runaway idel cranks fine idels fine then zoom....
Then the bogging when throttleing up to a plane. as I stated before if I push the key inwards to engage the primer
it takes off and hauls it. does this sound like what it would do with the problem I found.
90 lb's on all 6
great spark all 6
rebuilt carbs to the core!
drained gas and cleaned tanks
replaced water sep,filter and inline filter
replace gas lines
cleaned all gas tank vents
ck fuel pump all good
pumped gas bulb as it was running and changed nothing.
had everything looked over by pro seen nothing.
said to replace that carb should be fine??

 

[clevecan]

Re: cracked tube on johnson carb 150GT

anyone seen this before? And would it make the motor Bogg when trying to plane it
out?

 

[Cofe]

Re: cracked tube on johnson carb 150GT

I have not seen it happen with boat carbs, but with other motors they would have erratic behavior. The tubes would act like tuning forks throwing gas droplets at random. Some motors were uncontrollable.

 

[clevecan]

Re: cracked tube on johnson carb 150GT

It has a erratic behavior running away at idel here and there and of cource
the bogging prob. I just wanted to see if in fact! someone had this problem
with the cracked tube.
thanks Cofe.

 

[bignefan]

Re: cracked tube on johnson carb 150GT

I read a post hear a year ago,Same problem as your stating and if I remember he triied to fix with no luck.Replace carb and was good to go.I'll try a search and if I find it I will link it to your post

 

[clevecan]

Re: cracked tube on johnson carb 150GT

Sounds great, I had thought i'd seen one before as well a while back.I just wanted
to know if these cracked tubes make the motor act like that.
thanks again for your input.

 

[bignefan]

Re: cracked tube on johnson carb 150GT

Ok you'll have to search there are so many post regarding "emulsion tubes" most of them end up with the carb has to be replace.This is not a service able part.ya can't buy them.And many state eratic throttle.

 

[jim kinser]

Re: cracked tube on johnson carb 150GT

Clevecan,,,send me the model number on your motor, I've several carbs around. If I don't have a couple, I' got sources that may. PM me.

 

[clevecan]

Re: cracked tube on johnson carb 150GT

pm SENT thanks

 

[Jngserv]

2000 70 hp johnson. Replaced both tubes in carbs. Emulsion tubes all cracked. Was patched with a piece of arrow shaft over emulsion tube. Which did work. But mine had the small tube also cracked. Was unable to adjust idle mix. So i remove all tubes from carb. Made new ones. Ordered small tubing from mcelhenny. Used brass emulsion tube. It was .250 insted of .240 dia. The internal size was the same. Bored carb to press in new tube. Drilled and sized exactly the same. Then idle tube small dia. .095. I used a stainless steel tube and locktite all in place. Better than new. Planning on doing all 6 carbs. Both motors.

 

[racerone]

Very good work.------But not everybody has the resources or will to do that type of work.

 

[GA_Boater]

And on that note - Back to sleep.

Closed.