Fouled Main Jet?

[Sony2000]

Have you cleaned the two pinhole jets in the throat of the carb?

[Administrator]

You might be interest in this.

Bill

[a.flood]

Ed,

I had noticed this too. If you don't hear from me or hear a big bag, you'll know not to follow this way:-)

For regular moisture, one can recover the desiccant by drying it in a oven. With these vapors I think that might be a bad idea.

Aongus

[brianm132]

Have you cleaned the two pinhole jets in the throat of the carb?

Yes, I have broken down the carb at least twice.

[brianm132]

I see I began this thread on April 9th. I came down for a nice full moon sail and wouldn't you know it. She won't start! I'll see what's in the videos.

[Mo]

Don't assume it's the carb Brian. Make sure you have fire there bud. I'll just mention something here for a moment and let the others chime in. I am not as good at this as some of these other guys on here.

I wonder if you have a weak fuel pump. You change out filters and it is able to pull gas through new filters easily but as they collect debris (from Hanley's earlier post) the pump might not be able to get it done....just an idea and I would advise talking with Hanley or Dave Neptune before moving on that.

Sorry to hear your night didn't go as planned. Still a little cool hear but it is calm and we are looking at the same moon.

[Sony2000]

Previously you had a defective OPSS that you bypassed to get the engine to start.
If you are still running without it, the pump can overfill the bowl, and the gas will accumulating in the flame trap. I personally like turning over the engine BEFORE the pump activates. These engines need only a little choking to start, and I want to be the one doing it.

[brianm132]

Previously you had a defective OPSS that you bypassed to get the engine to start.
If you are still running without it, the pump can overfill the bowl, and the gas will accumulating in the flame trap. I personally like turning over the engine BEFORE the pump activates. These engines need only a little choking to start, and I want to be the one doing it.

Well, I spent a couple of hours Friday night thoroughly cleaning out the carburetor. I also downloaded the troubleshooting video. I found it helpful in explaining why carburetors cause issues. I never thought of addressing the OPSS issue to fix the fuel flow. I don't understand how you turn over the engine before the pump operates. My starter switch will not engage without the ignition switch open. Once I open the switch the pump starts pumping. My thinking has been the opposite. I would let the pump operate for a few seconds before hitting the ignition. Also, I run the engine with the choke fully open for a minute or so. Then half open for about five before closing it completely. I read this as the the proper warmup procedure somewhere several years ago. When the engine was operating flawlessly that worked fine. I'll address the OPSS situation. BTW, I still have not change the fuel hoses.

[Sony2000]

Hi. Not to overwhelm you, the OPSS lets electricity flow thru it when it senses oil pressure. A safety feature. It can be used to start the coil, and or, the fuel pump. Previously yours was probably connected to the coil, and certainly not the fuel pump. Since you have cleaned the carb a number of times, the only things to be confident about are, that the float needle is seated when the float plate is horizontal, and that air is not being sucked in where the clam shells of the carb meet.

[roadnsky]

Brian-
Mo and Sony have given you some good suggestions as to places to investigate.
Getting the carb video download is great for understanding the heartbeat of your A4 too.

Question...
Are you SURE that the choke is adjusted properly? Is it closing completely?
Take the flame arrestor off and look in there to be sure.
"Whenever an Atomic 4 starts hard, but then runs OK after it starts, the problem is almost always found to be a choke adjustment that does not quite close the choke completely. Because of the updraft design of the carburetor, it is necessary for the choke to close completely for a quick start."

And, I have to say it...
Be sure your water intake is closed until it starts.

[Cellnav]

Main Jet

Not to get off the subject, but is there a way to clean the carb out without removal and disassembly? Spray carb cleaner in the bowl drain plug?

[hanleyclifford]

There is never any harm in blasting carb cleaner into any external orifice on the carb that you can reach. Good examples are the main jet and idle mixing screw (before backing it out, turn it to seat and record the position) but first prize is to back flush with the thin red tube that comes with the can. This does require removal and partial disassembly.

[brianm132]

Gotta do some bread and meat work for a couple of days before I'll have a chance to get back to the boat but I'll keep you posted on my progress.

Thanks for all the advice.

[roadnsky]

Brian-
Here's some reading material to take along when you do get back to her...

[brianm132]

Finally got back to the marina. I replaced the fuel hose and filter. I had a very difficult time getting the bowl off. I found a piece of hose in the line and a bunch of crude in the filter. When I tried to start her she ran for a few seconds then shut off. I took off the main jet plug and cleaned it out but it still would start. Tomorrow I'll take the carburetor apart and clean it. Bright spot - my buddy came by and took me for a sail.