Fuel leaks from enrichment choke pivot (new style carburetor)

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LSolheim

Member
Amphi started and ran/swam OK Thursday after an almost 2-year COVID hiatus (with StaBil treated fuel), but back in the boathouse we noticed a strong fuel smell.

Today car wouldn't start, but I found a significant leak coming from the enrichment choke pivot (this is a newer style carb). I removed the 'choke' pivot assembly, but saw nothing remiss. Interesting to note that the choke housing has no gasket between it the carb itself.

Any clues as to cause and/or repair? I rhought this enrichment choke only metered incoming air.

Thanks. Hope to get this resolved before Opening Day of Fishing!
 
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Ken Chambers

Platinum Subscriber
Hi Larry,

Unfamiliar with the "newer style carb" but it should be similar to the Solex.

Are you referring to the accelerator pump lever? If the diaphragm is leaking, fuel could come out where the lever pivots. And then drip down onto the hot exhaust manifold. Gotta love old carburetors.
 

LSolheim

Member
Tbanks Ken, but no, this is the opposite side of the carb from the the accelerator pump. The equivalent of the choke, but the "enrichment" is supposedly an improved feature.
Wondering if the needle valve might be clogged & stuck (if there is one) and fuel flow doesn't stop with the float rise. And how does one access float & needle in this newer carb?
Pending a response over the weekend I may need to givr Scott a call on Monday.
 

Ken Chambers

Platinum Subscriber
You're probably on to something. Dirt or debris. Disassembly and thorough cleaning and blowing out passages. Make sure the inlet filter is doing its job properly.

Good luck and let us know what you find.
 

LSolheim

Member
Plenty of Amphicar disassembly & repair in our over 100K miles of towing, swimming & driving, but carbs are new to me. Although not our exact carb, this video was explicit enough as a crash course to trigger a few remaining brain cells. I will pull the top & take a look at the float & needle valve this AM. Hopefully GI stocks a kit or parts for these, if needed.

12:18 Update: pulled the cover & inspected the float, pivot and needle valve. All appeared OK and valve sealed when pin was lifted. Upon reassembly the fuel leak from the choke pivot remains ...... grrrr

3/29 Edit: interesting there is no o-ring or seal in that enrichment assy. WIll procure and change the needle valve and try again after reassembly.
 
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SNOWBIRD

Amphicar Expert
Carburetor fit for Jeep F Head 4-Cylinders Engines
A good shot of Fuel enrichener side.
 

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LSolheim

Member
Carburetor fit for Jeep F Head 4-Cylinders Engines
A good shot of Fuel enrichener side.
Thanks, Gord. Any idea why I would suddenly get a fuel leak from the (enrichment) choke shaft? It seems mostly like a static leak, after the motor is shutdown -- probably as fuel is sucked into the carb when the motor is running ... ??
 

LSolheim

Member
Replacing the needle valve (& seat & top gasket) appears to have done the trick. As not a carburetor expert, my theory is that the seeping needle valve allowed the bowl to overfill, then when engine was off that excess fuel no longer being drawn into the engine would leak down the enrichment port and out the choke assy. Will do much more testing after the heavy rains stop. Thanks to all that responded either here or personally.
 

RalphF

Member
Replacing the needle valve (& seat & top gasket) appears to have done the trick. As not a carburetor expert, my theory is that the seeping needle valve allowed the bowl to overfill, then when engine was off that excess fuel no longer being drawn into the engine would leak down the enrichment port and out the choke assy. Will do much more testing after the heavy rains stop. Thanks to all that responded either here or personally.
Do you have the fuel cutoff solenoid valve (what they call the "Magneto") installed? I think it is supposed to prevent this.
 

LSolheim

Member
Do you have the fuel cutoff solenoid valve (what they call the "Magneto") installed? I think it is supposed to prevent this.
Thanks, Ralph. Yes, I have the magneto valve installed and it does a fine job of stopping potential siphoning of fuel from the tank, specifically when parked on a slope and the engine is lower than the fuel tank.

As noted in my previous post, this was apparently a needle valve that did not fully seat, allowing the carburetor bowl to overfill.
 

RalphF

Member
Thanks, Ralph. Yes, I have the magneto valve installed and it does a fine job of stopping potential siphoning of fuel from the tank, specifically when parked on a slope and the engine is lower than the fuel tank.

As noted in my previous post, this was apparently a needle valve that did not fully seat, allowing the carburetor bowl to overfill.
Where did you obtain the parts. I think this carb is so new to us that no one has researched that yet, except you.
 

LSolheim

Member
Where did you obtain the parts. I think this carb is so new to us that no one has researched that yet, except you.
Turns out I puchased this carb in 2016. There is no part number or schematic that I could find.

I ended up talking with Scott @ GI. Besides the carbs he told me he purchased a few rebuild kits & apparently scavanged the needle, seat & gasket from one of those. This needle assy is much larger than in the stock carb.

If you are considering the change, make sure you look at the previous thread on this carburetor for detail of the required modificatons to the flame arrestor and (at least in my case) the manofold mounting studs
 
Larry,
Got one of the new units last spring. They have a larger bore throat, which in my mind is greater air flow and more HP!
Opened up the clearance on the mounting plate that holds the linkage to match the carb.
I did not modify the flame arrestor, just gave it a slight turn. It sits a little crooked, but so what? Did not want to do any "clearancing" on the expensive flame arrestor.
The studs are an issue as the mounting flange of these carbs is thicker. If you are lucky you may have a longer stud that can simply be screwed out for the extra threads. If not, just get longer ones.
Mine runs so much better with the new carb after a year of use. I also had an issue with throttle response, but Scott helped me out as well.
 
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