Hello fellow A4 sailors!
For the past six months, I've been struggling with problems in my fuel system, which have been caused mainly by the excessive debris in the fuel tank. I'll tell the story in reverse since I'd like to hear what you all have to say about my current problem.
Right now, the motor starts with a heavy throttle and cuts out if I bring it down to 2000 rpm. This happens when the engine is cold or at full operating temperature, with the choke on or off. I have adjusted the idle mixture screw, from 1/2 a turn out to 4 turns out, but with no change.
I am currently using an plastic outboard tank with fresh fuel. I have a racor filter/separator feeding an electric pump followed by an inline filter before the carb. I recently removed the carb, took it apart and cleaned it (before I did this, the engine would only run for a few min before dying).
Now for some history ...
About six months ago, I had the tank removed and chemically cleaned after I looked inside and discovered about a half an inch of debris in the bottom, including an old pickup tube which had broken off years ago. I was there when the guys removed the tank (and when the 4-5 holes in the bottom of the tank showed themselves!), but I wasn't there when they put it back in, so I didn't get to inspect the inside before it was re-installed.
After the tank cleaning, I removed and disassembled the carb and gave it a thorough cleaning. I added enzyme stabilizer to whatever I fuel I put into the tank, and tried to keep it as full as possible to avoid condensation build up. This seemed to solve the fuel system problems, but with time the engine began running poorly again, and then had problems starting. A couple of months passed where the boat sat idle and more than likely condensation built up in the tank again.
In December, I began working on the boat again, specifically on getting the engine to run again. Suspecting water in the tank, I collected a sample from the racor and the fuel was the color of apple juice, as it had been when I had the tank cleaned back in July. I disconnected the fuel line from the tank and fed it into a jerry can of fresh fuel and the engine started (and restarted) and ran for about 15 min.
I drained the entire tank (it was full, naturally) and inspected the inside through the fuel gauge sender port. Although it was much cleaner than six months ago, there was still a substantial amount of debris in the bottom. I employed the plastic outboard tank expecting better results, but the engine would not start consistently. I recognized the symptoms of a dirty carb and so begrudgingly removed it, again, disassembled it, again, and cleaned it, again.
After a few tries, the engine started with the choke out and about 1/3 throttle. I let it get up to operating temperature and pushed the choke in and let it run some more. No matter what I do, the engine will not run below 2000 rpm.
My hunch is that there is still some blockage in the idle jet, but before I switched to the outboard tank and took the carb off, the engine ran at normal idle speed, although not consistently. The only other thing I can think of is a vacuum leak, but again, the 2000 rpm problem is new since the latest carb cleaning.
Right now I'm considering purchasing a rebuilt carb from Moyer to start fresh.
I look forward to all your wise and learned advice on this issue.
For the past six months, I've been struggling with problems in my fuel system, which have been caused mainly by the excessive debris in the fuel tank. I'll tell the story in reverse since I'd like to hear what you all have to say about my current problem.
Right now, the motor starts with a heavy throttle and cuts out if I bring it down to 2000 rpm. This happens when the engine is cold or at full operating temperature, with the choke on or off. I have adjusted the idle mixture screw, from 1/2 a turn out to 4 turns out, but with no change.
I am currently using an plastic outboard tank with fresh fuel. I have a racor filter/separator feeding an electric pump followed by an inline filter before the carb. I recently removed the carb, took it apart and cleaned it (before I did this, the engine would only run for a few min before dying).
Now for some history ...
About six months ago, I had the tank removed and chemically cleaned after I looked inside and discovered about a half an inch of debris in the bottom, including an old pickup tube which had broken off years ago. I was there when the guys removed the tank (and when the 4-5 holes in the bottom of the tank showed themselves!), but I wasn't there when they put it back in, so I didn't get to inspect the inside before it was re-installed.
After the tank cleaning, I removed and disassembled the carb and gave it a thorough cleaning. I added enzyme stabilizer to whatever I fuel I put into the tank, and tried to keep it as full as possible to avoid condensation build up. This seemed to solve the fuel system problems, but with time the engine began running poorly again, and then had problems starting. A couple of months passed where the boat sat idle and more than likely condensation built up in the tank again.
In December, I began working on the boat again, specifically on getting the engine to run again. Suspecting water in the tank, I collected a sample from the racor and the fuel was the color of apple juice, as it had been when I had the tank cleaned back in July. I disconnected the fuel line from the tank and fed it into a jerry can of fresh fuel and the engine started (and restarted) and ran for about 15 min.
I drained the entire tank (it was full, naturally) and inspected the inside through the fuel gauge sender port. Although it was much cleaner than six months ago, there was still a substantial amount of debris in the bottom. I employed the plastic outboard tank expecting better results, but the engine would not start consistently. I recognized the symptoms of a dirty carb and so begrudgingly removed it, again, disassembled it, again, and cleaned it, again.
After a few tries, the engine started with the choke out and about 1/3 throttle. I let it get up to operating temperature and pushed the choke in and let it run some more. No matter what I do, the engine will not run below 2000 rpm.
My hunch is that there is still some blockage in the idle jet, but before I switched to the outboard tank and took the carb off, the engine ran at normal idle speed, although not consistently. The only other thing I can think of is a vacuum leak, but again, the 2000 rpm problem is new since the latest carb cleaning.
Right now I'm considering purchasing a rebuilt carb from Moyer to start fresh.
I look forward to all your wise and learned advice on this issue.
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