Stripped threads on carburetor

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jeremyhale

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Jul 12, 2021
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I was checking the screen in the carburetor for any debris. Went to tighten the inlet fuel nut into the carburetor, and tightened it a little too tight. Stripped the threads and now fuel spews out of gas line. Needing recommendations on how to fix threads on carburetor so I can still use original fuel inlet nut. I tried going around looking for heli coils, but no luck. A person said since that since the threads on the inlet nut are compression/ tapered threads, a normal self tap will not work. Don’t know if I should just self tap the carburetor, and use liquid thread seal, or go the route to purchase heli coils
 
Bondo

Bondo

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Ayuh,....... I see 2 options,..... The Best, would be to find a used carb body casting that ain't stripped out,....
A person said since that since the threads on the inlet nut are compression/ tapered threads,
Click to expand...
I don't see taper, nor a compression fitting,...
I believe, originally, there was a sealing washer 'tween the brass, 'n aluminum casting to seal it,.....
The line, 'n it's nut are plain ole flare fitting,....

If the flare seat in the brass fitting is undamaged, so it'll seal,....
I'd dig out that screen, 'n toss it, fuel filters are for cleaning the gas,....
Then glue the brass fitting into the carb body,.....
After yer glue of choice sets up solid, screw the line back in-place, check for leaks, then go boatin',.....

Maybe JB Weld, or something like that for a glue,....

'n Always use 2 wrenches when removing the flared fitting,....
1 to turn the flare nut, 'n another to fit the brass fitting it screws into,....
 
ESGWheel

ESGWheel

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This is a challenge and while I have never tried to do this, it occurs to me that anything less than 1000% positive of no leaks is not worth it. Leaking fuel on a boat that could result in a fire is not like having a fire at home where you can simply walk outside. I have read in other threads that reconditioned carbs are not that expensive. Post your info about boat, motor and carb and there are folks who can help guide a replacement carb or provide other ‘fix it’ info.
 
J

jeremyhale

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I have a 4.3 Volvo engine. I entered the model number on the Volvo penta website, and the carburetor they have listed is for a V8 Volvo penta. IMG_5038.jpeg
 
C

cyclops222

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Gasoline leaking out becomes drops dripping on hull bottom. which evaporates into GASOLINE FUMES !! That can fill up the boat............. Do the carburetor body replacement routine.
 
Scott Danforth

Scott Danforth

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I would get a new carb.

if it was a holley 4150/4160/2300 series, a new bowl would be all you need.

no need to be more than one finger on the wrench to tighten an inverted flare fitting.

that little screen in there does nothing. it has a rating of 150 micron. which means that large chunks make it thru. the 10 micron filter you have by the fuel pump is your filter.
 
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Chris1956

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If you have sufficient room on the carb body, you could drill and retap for a flush bushing. You would need to find a flush bushing that fits the fuel line, and get the right tap and drill for the male part of the flush bushing.
 
J

jeremyhale

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Jul 12, 2021
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There are some numbers on my current carburetor, and when I search them up, they bring up a whole different carb wher the fuel inlet is in a totally different position. So would need new fuel line as well if I went that route. These are the numbers I found on the carburetor. IMG_0105.jpeg
 

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S

stouchton

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Feb 12, 2018
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I did this to a Rochester nearly 50 years ago - they made a replacement fitting that cut new threads as you cranked it in. I do not remember what that fitting was called, but it did exist.

Also - you could drill out and tap the carb for a larger fitting, then use a nipple and piece of fuel line to connect. Never fun messing with fuel connections on a boat though. Replacing carb or housing would be safest.
 
Scott Danforth

Scott Danforth

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stouchton said:
Also - you could drill out and tap the carb for a larger fitting, then use a nipple and piece of fuel line to connect. Never fun messing with fuel connections on a boat though. Replacing carb or housing would be safest.
Click to expand...
no way to safely drill and tap for an SAE J512 port without the proper port tools and tap, especially in a zinc carburetor body
 
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stouchton

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Scott Danforth said:
no way to safely drill and tap for an SAE J512 port without the proper port tools and tap, especially in a zinc carburetor body
Click to expand...
Do you think a brass NPT hose barb would be out of the question? It does look like the wall is pretty thin. I never tapped zinc, though that fitting did cut new threads on the Rochester and I am pretty sure that was zinc.
 
Scott Danforth

Scott Danforth

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You will never get an NPT fitting to seal. I wouldn't chance a hokey repair. In a car, if you have a fuel leak, you just loose fuel. Possible chance of fire.

In a boat, a fuel leak means you meet Jesus in a million burning pieces
 
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