Is my air horn broken?

[ZZ13]

I have an air horn driven by a little Wolo 12v pump. I think I could toot the horn as long as I wanted when I surveyed the boat, but don't really remember. Last outing the horn would only do a short toot no matter how long I held down the button. And I couldn't get it to toot back to back right away. I had to wait a little while. So I replaced the pump. Now it toots every time, but it's still only a short toot, no matter how long I hold the button. So I can't do a long toot. Is something wrong or is this working as designed?

Only thing I noticed is the air hose slips on really easy at the pump. Should I cut it back to unused hose to make for a tighter seal?

 

[trit21]

Couple things you can check.

1) Verify no water is in the line from the compressor to the horn.
2) Sometimes when water gets inside the horn, it kind of screws them up and they need to be taken apart, the reed (plastic dohicky that make the noise) get wet and dirty. Cleaning will make it work much better.

BTW, you can probably take apart the compressor, clean, oil and it will work fine. Not sure what type you have so not sure about that but my AFI gets corrosion build up and once a year I take it apart and clean it.

 

[JimFromMD]

Maybe gently shoot some compressed air (air duster can / air compressor) down the trumpet side too. In exploring the idea of upgrading my duck-with-laryngitis horn, I read where sometimes spiders make nests in them, or something blows down inside the trumpet while under way. Could be something trapped and preventing the reed from vibrating? Just another guess.

 

[Fred]

I had the same short toot from one horn and then nothing.
I removed the horns and disassembled the back ends cleaning the mylar diaphram and metal surfaces it contacts.
When it is right you can easily blow into each horn producing a strong sound. They now work perfectly.

 

[Alex F]

Mine went from weak to dead recently. An easy fix was taking the horns out and cleaning the diaphragm. I wish every issue was as easy as fixing the horn.

BTW, the compressor is low pressure one, so even though the hose does seamed to be kind of loose, it was still working fine with clean horns.

 

[PMC]

Blow into the end of the hose (mouth)...it is enough pressure to sound it. I would cut it back for a tight seal. I probably have the same compressor pump. It is supposed to be oiled regularly, or so the sticker says. Might need servicing.

 

[ZZ13]

Wow, way to rally to my aid. Thank you all very much. I didn't know a darn thing about this and now you've given me places to look.

It's real easy to remove the horn. I'll take it off and clean it up as best I can and see what happens. Also, the pump was less than $20 so no real waste in buying it. Now I have a spare

 

[Alex F]

.....what they don't tell you, unless you call them, is to reverse the positive and negative power leads so that the compressor sucks air rather than blowing it. If you don't, you'll blow the oil out of the compressor before it has a chance to do anything. There is an air intake on the side of the pump, but the techs at AFI did not recommend putting the oil in it for some reason which is beyond me.

That's a good tip, Scott. Thanks for sharing.

 

[Art]

One note on oiling, the method is to drop one or two drops of light oil in the output hole.....what they don't tell you, unless you call them, is to reverse the positive and negative power leads so that the compressor sucks air rather than blowing it. If you don't, you'll blow the oil out of the compressor before it has a chance to do anything. There is an air intake on the side of the pump, but the techs at AFI did not recommend putting the oil in it for some reason which is beyond me.

Scott, I must have gotten a better AFI tech, he recommended:
1) disconnect air line
2) 2 drops of oil in pump
3) reverse leads
4) run air pump for a few seconds to draw in oil
5) put elect. leads back to original position.
6) cover air pump inlet with clean rag
7) run air pump to blow out excess oil/debris
8) reconnect air line.

You might be surprised to see what comes out of the air pump, and you don't want that working its way down the air line into the horns.

Art

 

[hottoddie]

ZZ13 In another thread you mention low voltage output on the port engine. If true it may be related to the lousy air output from the compressor.

 

[ZZ13]

I took the horn off. Took it apart. Cleaned the plastic film (reed?). And put it back together. That did the trick. Dock mates got tired of the long toots while I tested the repairs. Take a look at what 13 years of salt spray does to a horn. Not sure if I could replace it - searched online and couldn't find anything like it. It mounts in the anchor locker and according to the parts manual for my boat is supposed to be a dual horn. But its just this one horn. The second opening for the other horn is vacant.

 

[Art]

Bill, Good job!! My trumpets are located in my anchor rode locker and it seems impossible to get them out. Are yours similarly installed, and if so how did you remove them?

 

[ZZ13]

Bill, Good job!! My trumpets are located in my anchor rode locker and it seems impossible to get them out. Are yours similarly installed, and if so how did you remove them?

The horn on my boat is mounted to a piece of starboard that has the holes cut out in it for the horn ends. That starboard is held to the locker with four screws. I removed the four screws and there was plenty of slack in the air hose to lift the whole thing out of the anchor locker. Then I removed the horn from that starboard. It was held on with an angle bracket.

 

[Art]

The horn on my boat is mounted to a piece of starboard that has the holes cut out in it for the horn ends. That starboard is held to the locker with four screws. I removed the four screws and there was plenty of slack in the air hose to lift the whole thing out of the anchor locker. Then I removed the horn from that starboard. It was held on with an angle bracket.

Bill, thanks. I'll I'll give it a try, but my access is so tight that even with the anchor rode locker hatch off, I can not even feel or see the screws securing the board on top of the sound box.

 

[ZZ13]

Well. I decided to go all in on fully replacing the horns. Below is what I started with. One horn missing, and the other horn nice and weathered looking plus cracks starting to show in the reed housing.

Thanks to a thread here found during a search, I discovered the part number for the dual curved horn kit to be AFI 11058. I ordered it online and here's the new configuration.

I now have a spare horn, two spare pumps and a whole bunch of extra tubing. Since all that came with the kit.

 

[Arl798]

Hey ZZ13...I have the 99 400 DB and my horns have never worked since I bought the boat 3 years ago. I see the photos of yours and mine def. do not look like that. Was curious how you gained access to yours. Mine are port side in the anchor locker and the hatch is on the starboard. My mechanic in Mexico removed fixed then replaced my windlass and brought his 10 year old son to fit in the hatch. Any other options than that? haha

 

[ZZ13]

Mine is right there inside the anchor rode locker. Did you get a left handed 400DB? My dockmates 99 400DB has his on the same place as mine. Do you have pictures of yours you can post?

 

[Arl798]

I will take pictures when I get back to the boat for sure. Left hand 400DB? Is that like a left handed wrench or is this a real thing? haha From what I recall my trumpets are just 2 side by side air horns inside the locker and there is a fiberglass cover that lets the noise out. I see yours curve and go right against the hull and out. Mine don't do that.

Mine is right there inside the anchor rode locker. Did you get a left handed 400DB? My dockmates 99 400DB has his on the same place as mine. Do you have pictures of yours you can post?

 

[ZZ13]

Yes, just a joke. Yours may have been replaced by a previous owner