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Carb cleaning ?

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billyvray

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Joined
Aug 17, 2005
Messages
806
Location
Newnan, GA
I have a Bing slide carb for a 2SI engine on an Ultrastar. It sat for years and I have been attempting to clean it up. I just cannot get fuel to flow through the fuel inlet tube to the bowl.

So far I've done these things:
-carb cleaner
-seafoam
-boiled in lemon juice/water
-high pressure air

I still cannot get fuel to flow into the carb. Even when plumbed up I pressurized it with the primer bulb and nothing...I have never had a carb give me this much issue. I've tried running a small piece of safety wire into the tube but the angles it takes prevents full reach.

At this point ultrasonic seems to be my only next step. I would appreciate any other help.


Bill
 

lake_harley

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Joined
Jan 4, 2007
Messages
970
Since you boiled the carb in lemon juice/water, I guess the carb is off and disassembled, right? But, your problem is still that fuel won't flow from the inlet nipple into the fuel bowl? Is the float and needle out? I use MEK for cleaning carb parts, but that might be such a nasty chemical to some that they'd avoid it.

Lynn
 

Turd Ferguson

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Mar 13, 2008
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Location
Upper midwest in a house
If the bowl is off and needle valve removed, it should be an unrestricted path for fuel to flow. Replace needle valve and seat.

Have seen needle valves stuck in a seat before like it was welded.
 

billyvray

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Aug 17, 2005
Messages
806
Location
Newnan, GA
Yepper doo, the carb is completely torn down. The fuel will not flow from the inlet tube orifice through the needle seat orifice. There is nothing visible blocking the holes. And, I can't fish a wire through the tube because of the angles it takes.
The seats all look good...
I have not tried MEK but will try that...

Bill
 

Hot Wings

Grumpy Cynic
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The seats all look good...
I have not tried MEK but will try that...
MEK has such a high vapor pressure it tends to boil off before it gets the job done. Mixing it with a little Xylene helps. The old school standard is/was methylene chloride. Makes MEK seem water safe by comparison, but it gets the job done. Expensive to buy as carb cleaner - if it's even available in your area. You can extract the MC from paint stripper but that gets to be another nasty job that should only be a last resort.

Not knowing your particular carb: Can the needle seat be removed?
 

TFF

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Apr 28, 2010
Messages
13,792
Location
Memphis, TN
Just asking, but has this carb run the engine before? If not could be not fully machined right. If it has and compressed air has not blown it out wow. Are you using spray car cleaner or dip? I like spray; it seems more capable. An old crock pot, never to be eaten out of again, filled with hot anti freeze is popular with RC people to clean the engines. Takes the varnishes off without harm.
 

billyvray

Well-Known Member
Joined
Aug 17, 2005
Messages
806
Location
Newnan, GA
This is a 32mm Bing slide carb I'm using with a 2SI 460 two stroke engine (very similar to an old Cuyuna).
The carb has run the engine in the past, though it has been a long time. Fuel hoses were rotten so a proper cleaning was in order. It looks brand new now. I'm guessing i have a hunk of goo from rotted fuel hose stuck in it but i can't for the life of me imagine it not getting loosened up by all the junk of thrown at it.

I don't think the needle seat can be removed.

I've never heard of a hot antifreeze bath, but may try that too.

May even just try hitting with some propane to burn it out.

Bill
 

Dana

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Staff member
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Apr 3, 2007
Messages
9,435
Location
CT, USA
Even with a bend in the passage, you should be able to poke something through from each side and at least see in the bottom of the other side... it had to be drilled (or cast with core pins) in the first place, anyway. Unless there's a third passage segment drilled from somewhere else and plugged afterwards.

Dana
 

billyvray

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Joined
Aug 17, 2005
Messages
806
Location
Newnan, GA
Well, wonder of wonders, I got it unstuck. Soaked with Seafoam then managed to get a piece of safety wire bent in just the right configuration and fit it through. Nice little plug of debris popped out and broke up easy as you please and now I'm back in business.

Amazing it took me 47 tries of doing very similar actions before it worked. It's also amazing how tough one little piece of debris could be...

Bill
 
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