Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem
Model 17082403 fuel leak only after shut down, Crusader 454 engine
Cliff Ruggles:
Leaking after shut down could be many things.
Miss-matched parts will cause that problem IF the upper idle airbleeds aren't in place to "vent" the flow from the idle tubes to the discharge ports.
A leak under the fuel inlet seat will also cause this as an residual fuel pressure in the line will continue to fill the carb till it overflows from the boosters.
Bad needle/seat assembly is another cause.
Very few Marine carburetors had PCV or any other vacuum ports for vacuum advance and such as most didn't use either.
Pics of the carbs will help me identify them......
BarryK3:
Cliff,
You are completely correct. I was mistaken. The leaking "exchange" carb is NOT an original marine model. I thought it was the same as the other one. The model number is 17000580. It has a straight vent, not an angled one.
I returned it to the carb shop today. He is rebuilding my original one (the "core" that I gave him) and it will be ready tomorrow. I hope that it is a marine model. I believe that it is.
The first picture is a poor picture of the model number on the leaking carb, hard to read. It is painted black.
The last 2 pictures are of the working carb that he recently rebuilt, model 17082403.
The local guy runs a very clean professional shop and does good work. I just don't think he is familiar with marine parts. He deals almost exclusively with automotive.
Assuming that I get back a 2nd working marine carb, what should I do next? Should I replace the accel. pump skirts on both with the ones that you sell?
Thanks so much,
Barry
Cliff Ruggles:
You are extremely fortunate to still have access to the original Marine units. Marine carburetors are NOT the same as automotive units and it's not just the calibrations. They are specifically built and designed to power engines that are heavily loaded most of their life, so they have specific parts, features and take different rebuild parts than their automotive cousins. Failure to use the correct parts is why I get so many in here that don't work well or at all.
I haven't had a "rebuilt" Marine unit come in here in at least 10 years with the correct parts in it. I get them in here all the time "freshly" rebuilt and not working.
All of the kits being supplied in the aftermarket have the wrong parts in them, but I'm not going into great detail to help out the folks supplying them.
They do not come with a good pump seal either. NONE of the blue seals that show up in over the counter and on-line kits will hold up in this new fuel.
You just found that out if one of the carbs placed in service didn't have any pump shot. I test the seals being supplied in kits and on occasion I have to grab one locally if I'm out of stock on a gasket or two. I submerge the pump in fresh fuel and usually within an hour or so the "blue" seal is swollen to nearly two times it's original size.
I preach using good parts all the time, and a lot of "builders" are getting my parts, but sadly many still build carbs using "kits" obtained locally or what is being supplied by the vendors who still sell parts for these carburetors......FWIW......Cliff
BarryK3:
I brought back the "exchange" carb today and got my original one back, cleaned up and looking good. Thank you so much! I got it before someone else did. So now I have 2 original marine units, identical. I installed and ran the one I picked up today and NO LEAKS of course!
You were a huge help Cliff! I will be purchasing 2 of your rebuild kits soon. Do you have rebuild instructions on this site or can you recommend where to get them?
Thanks again,
Barry
Cliff Ruggles:
Good news. There is a link in the package with the kits to basic instructions, plus I put a list of Marine kits by carburetor number in with them so you know the float levels and basic settings.
In the kits you'll find the correct high flow Marine Viton N/S assemblies, correct HP Marine pump with a stainless steel return spring, chrome vanadium duration spring, and lifetime warranty pump cup w/garter spring.
The main body to airhorn gasket is also made from a better material and .015" thicker for improved sealing.
I ship the same day if ordered before apprx 11am...tks...Cliff
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