New Weber 32/36 leaking throttle area.

[Jetboater Pop]

Hi there . 
I have an issue with a brand new Weber 32/36 that leaks fuel from the front throttle body after I shut off the engine and it is sitting. Datsun L16 engine.

Ive checked and double checked the float height. Im sure it is correct.

The engine runs very well. Starts well , idles well.

It runs a standard L16 mechanical fuel pump.

The first thing I was told is that the fuel pressure may be too great and I may need a fuel pressure regulator .

Are the Redline ones that have a dial on top good enough ?

The other thing that Ai Google finds is that I may need a phenolic / heat insulation block between the carb and manifold ?.

currently it doesnt have one as the original Hitachi  Datsun one didn’t fit when putting on the new carb.

Its really important that the engine has no fuel leaks as Im running it in a small Jet boat.

Any thoughts, thanks in advance, Paul.
 

 

[ruthwren88]

 

Jetboater Pop said:

Hi there .
I have an issue with a brand new Weber 32/36 that leaks fuel from the front throttle body after I shut off the engine and it is sitting. Datsun L16 engine.

Ive checked and double checked the float height. Im sure it is correct.

The engine runs very well. Starts well , idles well.

It runs a standard L16 mechanical fuel pump.

The first thing I was told is that the fuel pressure may be too great and I may need a fuel pressure regulator .

Are the Redline ones that have a dial on top good enough ?

The other thing that Ai Google finds is that I may need a phenolic / heat insulation block between the carb and manifold ?.

currently it doesnt have one as the original Hitachi Datsun one didn’t fit when putting on the new carb.

Its really important that the engine has no fuel leaks as Im running it in a small Jet boat.

Any thoughts, thanks in advance, Paul.

 

Fuel dripping after shutdown sounds more like the bowl is getting pushed past its limit than a throttle-body issue. Those little dial regulators have a pretty mixed reputation, especially when a leak-free setup matters this much.

[datzenmike]

5 hours ago, Jetboater Pop said:

Hi there . 
I have an issue with a brand new Weber 32/36 that leaks fuel from the front throttle body after I shut off the engine and it is sitting. Datsun L16 engine.

Ive checked and double checked the float height. Im sure it is correct.

The engine runs very well. Starts well , idles well.

It runs a standard L16 mechanical fuel pump.

The first thing I was told is that the fuel pressure may be too great and I may need a fuel pressure regulator .

Are the Redline ones that have a dial on top good enough ?

The other thing that Ai Google finds is that I may need a phenolic / heat insulation block between the carb and manifold ?.

currently it doesnt have one as the original Hitachi  Datsun one didn’t fit when putting on the new carb.

Its really important that the engine has no fuel leaks as Im running it in a small Jet boat.

Any thoughts, thanks in advance, Paul.
 

 

 

Stock Weber.... There are a lot of counterfeit Webers out there on sale. A good original and new Weber would be close to $400 these days, is made in Spain and  usually says so on the casting. Red Line sells them through Pierce Manifolds. A 'knock off' can still work but usually poorer quality.

 

 

https://www.pafclassic.com/en-fr/blogs/carburation-weber/identification-et-numerotation-des-carburateurs-weber?srsltid=AU7gw4XIHXOWhQO0j5keVSjfpeisLpSPs3Gh9EYlz5tJyz_FnPDDk_OG

 

 

 

Stock mechanical fuel pumps are fairly reliable for output and pressure, about 3.5 to 4.5 PSI. This could simply be that the fuel bowl is over full and as long as engine is running isn't a problem. After shut down remove the top of the Weber and see if float bowl is filled to the brim or not. Check the inlet needle valve is clear of debris that may be not allowing it to close properly. 

 

Is it leaking at the gasket? Generally the fuel level is below the gasket and it only contains fuel that is splashed around. Check the sealing surfaces.

 

Check the external fuel line/hose to the Weber is tightly connected.

 

The phenolic spacer is really a heat barrier more than anything else. More important on a vehicle than a boat I would imagine.

 

Jet boat or vehicle, any fuel leak is important.

 

 

[gfrosthare]

 

Jetboater Pop said:

Hi there .
I have an issue with a brand new Weber 32/36 that leaks fuel from the front throttle body after I shut off the engine and it is sitting. Datsun L16 engine.

Ive checked and double checked the float height. Im sure it is correct.

The engine runs very well. Starts well , idles well.

It runs a standard L16 mechanical fuel pump.

The first thing I was told is that the fuel pressure may be too great and I may need a fuel pressure regulator .

Are the Redline ones that have a dial on top good enough ?

The other thing that Ai Google finds is that I may need a phenolic / heat insulation block between the carb and manifold ?.

currently it doesnt have one as the original Hitachi Datsun one didn’t fit when putting on the new carb.

Its really important that the engine has no fuel leaks as Im running it in a small Jet boat.

Any thoughts, thanks in advance, Paul.

 

Fuel pressure can still be the culprit even with the float set right, those little dial regulators are pretty hit-or-miss. A heat spacer might help hot soak, but fuel coming out the throttle area after shutdown sounds more like the bowl is getting overfilled.

[Jetboater Pop]

Cheers guys. The more I think about it Im tending to think its fuel pressure although it does get quite warm under the engine cover.

when I think back , one of the reasons I replaced the old carb was the issue of it leaking/ dripping around throttles and base and the tubes seemed full of fuel.
No matter how many times I pulled it apart I never got on top of that issue. It was stuffed anyway , had served me well for 40 years.

its a genuine Weber Mike  from a reputable supplier ,paid an arm and a leg for it here in NZ with the mounting kit and air filter.

When I pulled the top off to check the float height the bowl it wasnt full to the brim at all, maybe about 10 cm?.

Everything is perfectly clean and I took time prepping surfaces etc. Initially I thought gaskets but Im sure its coming from the front throttle and dripping down.

The reason I asked about the Redline adjustable fuel pressure regulator is that theyre a cheaper option that doesn’t require a gauge to set it.

I read that fuel pressure can stay high after the engine is off but am not sure thats true.

If that were the case fuel  may look for an outlet especially if its hot. 
when I popped the top off the carb off the remaining fuel was quite warm.

Any other thoughts appreciated.

Cheers, Paul.