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I bought a c&c 30 and tank full of water and dirt. Cleaned tank replaced lines and filter and flushed new clean fuel to the carburetor. But now carburetor is the problem and I don't know how to clean out a carburetor. Main concern is I take everything apart to clean. Do all the parts just get placed or screwed in or do I have to screw something in to the bottom and count turns so I can put it back properly? Which item and how touchy is this???
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Cleaning the Zenith carb for the A-4 is actually quite simple especially if you pay attention to the important details.
First get a good carb kit and some carb cleaner spray. If you can't find the carb spray brake cleaner will suffice. Another item is to have access to compressed air and an air hose for blowing out the passages.
Once the carb halves are apart you will need to take out all of the brass jets you see. IMPORTANT only use a screwdriver that fits snugly as the jets are soft and can be held tightly in the softer material of the carb. It is better to eave the jet in place than to destroy it.
Get a fine wire like from a "bread tie/twist tie" or strip a piece or copper wire. These are to poke through the "idle ports" which are located in the throttle body, one above (the slow idle) and one below (the high idle) the butterfly valve when closed. They are just a couple of "slots" that let in the aeriated fuel for the idle. Poke and use a lot of air with the cleaner.
The main jet and the hi speed air jet also need to be removed, sprayed and flushed with air. These ports are larger and not as fussy as the idle ports.
DO NOT remove the throttle or choke butterfly as setting those is very difficult for even an experienced carb guy!
Once the ports in the carb body are clean re-assemble and do not tighten as tight as they came out. They will grab the softer material of the carb body and stay put.
Now without the gasket or the float assembly installed hold the 2 halves together and hold up to some light. You want to see very little light or some honing may be necessary. We will cover this if you have a big gap. The seal in the middle of the bowl for the "hi-speed air corrector and emulsion well" are very important to overall carb performance.
Now it is time to adjust the float level, instruction should be in the kit. When adjusting only bend the "tab" that contacts the needle IE don't bend the float. Use 2 pair of needle nose pliers and bend slightly at a time. There are two adjustments to make at the same time one for the height of the float and another for keeping the float parallel at that height. I personally like setting the float lower than stock to lean out a bit a carb that is a bit to rich for the A-4. I set it at 1/16 lower than stock which means a larger gap or height when the top is inverted to check the clearance. This sound complicated but just take your time and you will find it is not really that big of a deal. PATIENCE
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As far as settings other than float level there is a "idle air jet" that is on the outside of the carb. It is set at approximately 1 1/2 turns out off the seat. Fine adjustments with that air valve can be done while the engine is all warmed up and idling. On a few carbs an adjustable main jet has been installed as a modification. If you have one it to starts out at 1 1/2 turns off the seat and is adjusted when running at a fast cruise or wide open throttle. I personally prefer a fixed jet as the adj jets can leak fuel if not properly adjusted and maintained.
Now install the gasket and tighten the screws gently crossing back and forth sequentially a tiny bit at a time. This will squeeze the gasket evenly for a good seal.
I do suggest 2 other items. First a polishing filter in front of the carb and a cheap pressure gage after the polishing filter. The gage can be a wealth of information in diagnosing fuel delivery or carb problems, well worth the investment.
Dave Neptune
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Thankyou so much for the time you spent giving me this valuable information!Comment
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I had no experience with carburetors either, but DN and the others helped me get through several issues. The tech video from Don Moyer is also very helpful to have playing on your phone while you work on the carb.
I would second the above opinion about the correct size slotted screwdriver, especially for the idle jet. I damaged mine with one that was too small.EJ
78 Catalina 30Comment
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Air trapped in carburator?
When I was talking to Ken from Moyer Marine one thing he mentioned is there can not be any air trapped in the fuel system. So I have taken the carburetor out and cleaned it. I had difficulty getting fuel to my carburetor and re installing it and I have replaced my after market Ele. fuel pump with another one and I am getting pressure to the carb. I know this cause when I try to remove my fuel line from the carb fuel stated to leak out under pressure. So the engine will not cough or start now. it is like I am not getting any fuel to the engine? could I have an air lock in the carburetor and if so How can I bleed air out of the carb??Comment
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If you have pressure at the carb there is only one way it won't get into the carb bowl and that is if the "needle" is stuck in the "seat".
When trying to start did you try any starting fluid (motor crack)? Give that a try before you try anything else. That will let you know if everything else is OK like the timing and spark. If it still does not sputter for a few seconds on the starting fluid you will need to look to the ignition.
There is always a bit of air trapped in the filters and possibly a high spot in a fuel line. What you don't want is for air to be sucking into the line reducing pressure and flow. The entire carb is exposed to air as it needs air on the "inside" to be balanced to the outside and that air is drawn and mixed with the fuel inside to aerate the fuel before it is delivered to the discharge to be mixed with the air being let in by the throttle.
Dave Neptune
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