Horn repair

[johnsw]

This is another one of those topics that has probably been beaten to death, but just curious if this has already been tried and what the end result may have been.

I know some have changed the location of the horn so it doesn't catch water and some have angled it down to help them last longer. Is there another option?

Having gone through 3 dual trumpet horns on my '04 2120SC, I decided to take my last one apart to see what the deal is. Basically, it's a metal diaphram that flexes back and forth very quickly to generate the sound. A solenoid on the inside (energized by the horn button at the helm) pulls the diaphram in and when that happens, breaks the electrical connection to the solenoid. When that happens, the metal naturally flexes back out which makes the solenoid electrical connection again, and the whole process repeats.

When I opened up my horn the trapped water leaked out and when I got it apart, I found the bottom half of the diaphram had a coating of rust to a level up to the trumpet opening where it connects to the part of the horn that makes the sound. Makes sense as any water level higher than that would simply come back out through the trumpet.

After removing all of the rust and polishing the diaphram, I reassembling the horn and once again had a functional horn that I'm planning to keep for the next needed replacement. It looks like when the rust coating gets thick enough, it may be restricting how the diaphram flexes (mostly when the electromagnet turns off is my guess). The rust was confined to only the surface of the diaphram that faces the trumpet. The backside was clean and the electricals (also on the backside of the diaphram) showed no signs of water exposure, isolated pretty well by the gaskets and diaphram.

Now, I'm wondering if anyone has tried putting a small (say 1/8") weep hole in the horn housing down low in the front of the horn housing where the trumpet connects? I'm thinking that would allow water to drip out and not accumulate, or at least not accumulate to such a high level.

I'm probably going to try it anyway now that I have a unit to experiment with, unless someone has already tried it and still had horn issues. But at least I now know that these horns, in some cases, are easily repaired.

Any thoughts?

John S.

 

[Bryan 2530]

Sounds like a plan, I tore my originals apart but they were too far gone, thought the same thing about the drain hole.

I put on a stainless truck horn last year and its still going, when it breaks I'll probably change the location.

 

[johnsw]

Seems like such a simple thing to do. And if it fixes what seems to be a chronic problem, then I can sell my AFI stock.

Not sure if it will affect the sound any, but got nothing to lose. If it doesn't work, I can always plug the hole.

As long as I can keep repairing them, I can keep recycling them until one craps out altogether and is beyond repair.

I toyed with moving it. I'm sort of OK with putting new holes in strategic locations now. It's just figuring out how to best patch old holes that keeps me from doing too many mods to what I already have. But I guess, one day I'll get over that one also.

John

 

[Brent]

I am away from my boat and the factory horns do not work. I think will work on them. How do they could apart?

thanks

 

[johnsw]

When my OEM Ongaro horn died, I replaced it with an AFI. It has the same footprint and darn near looked like the identical horn to me.

In my case, the horn would just burp when I pressed the button on the helm. That being the case, I figured the electrics were working and it was probably a mechanical problem. You can check the solenoids for continuity with an ohm meter. Resistance on these guys is only a couple ohms for each solenoid.

If they check out, then the horns come apart pretty easily. This PDF from the AFI website has an exploded diagram that's pretty typical:

http://www.marinco.com/files/media/product/catelogs/AFI electric tumpets.pdf

Remove the 5 screws from the horn, and the works will seperate from the trumpet. The metal diaphragm simply slips out of the solenoid core. There are paper gaskets on each side of the diaphragm, so handle them carefully if you want to reuse them when you put everything back together.

I was able to clean mine up with WD-40, fine steel wool and metal polish. Putting it all back together is just reversing the process. The only tricky part seemed to be keeping the gaskets placed properly until I got all of the screws started. I think when I take mine apart again to do the weep hole, I'll use silcone to seal it.

Since I already had mine all apart, I quickly ran some fine emery paper across the switch contacts just because I was there.

As long as the solenoids aren't opened, about the only actual electrical repair that might be needed is checking the electrical connections that power the solenoid, and cleaning the contacts of the mechanical switch on the back side of the diaphragm. If you have continuity, then your electrics are probably OK.

But if you need to get to those parts, there's a single screw in the center of the horn back (it may be covered by a label) that holds everything together. If you check continuity and the solenoids appear open, they actually might not be. Anything keeping the switch contacts from making good electrical contact (corrosion, oxidation) will give a false open on the solenoid coil.

Good luck. Post a reply and let us know what you find.

John

 

[Brent]

thank you John

I will try it. Somewhere I thought it could not be repaired or if it could the cost of the parts was better spent on a new horn

 

[johnsw]

No problem. There's really not a lot electrically that can go wrong with these things. Switch contacts can usually be cleaned up. Poor connections repaired. The solenoid coil is pretty thick guage wire, so it probably won't open due to a broken winding. And even if it did, from what I remember seeing, it shouldn't be too difficult to rewind with new wire. All that's left are the mechanics that make the diaphragm move and the lever mechanics they use to make the internal contacts open up..

John

 

[jrannestad]

I replaced my stainless bugle horn once with an identical horn and never used it once and when I tested in about two years after I installed it it was non functional. I replaced it with a $29 cheepo plastic one. We will see if this one lasts.

 

[rplas48]

I havea 2005 2120SC and the horns have weep holes at the bottom. I shoot some WD40 through a long tube untill it comes out the holes. Horn has been fine.
Ray

 

[johnsw]

Very interesting. Know what brand horns these are? Last AFI's I bought didn't have it, and I haven't seen any other Ongaros to compare with. Approx size of the opening?

John S.

 

[greatcir]

I like big horns on a small boat. My air horns always work perfectly unless it is below freezing and the air valve slows up. Still blows but starts slow & ends slow when that cold. A light tap on the switch is all I ever need to blow, even at the big guys....................Pete

 

[rplas48]

John S...their AFIs dual trumpets and the holes are about 1/16". The base is sealed so you can't take them apart. Glad for the drainage holes.
Ray

 

[Megabyte]

Pete... love those train horns!

 

[johnsw]

Yep. I thought about air horns. Figured next time I need to spend real money, I'd see what I can find before buying electric horns again. Enough money tossed into that hole. Since I've been repairing mine, I can milk them along a bit farther.

I guess AFI saw the error in their ways. I'll have to check them out again if I can locate a recently manufactured set. All the ones I've purchased were screwed together and no opening for water to get out. I've got a set of mine on the bench now. Figured I'd do weep holes at the bottom front of the horn body, and a small one on the bottom of the trumpet just before the weld to the horn front cover. That way, any water that gets in through the front and travels down the length of the trumpet might drip out before actually getting to the horn. They don't work they way they are, so nothing to lose.

John

 

[Megabyte]

Did some maintenance on my Ongaros this past week.
One horn works fine, and the other is intermittent, so I figured I'd try some PB Blaster first.

Shot a heavy dose of PB Blaster into the horn, then stuffed the bell opening with a paper towel.
Came back the next day and did it again.
On the third day I followed up the PB Blaster with WD40.

Each time I shot PB Blaster into the horns I laid on the horn button trying to get some action out of that solenoid on the horn disk.
With the paper towels stuffed in the bell, I didn't annoy everyone in the marina.

Went out fishing the other day and passed a friends house on the creek and gave the horn a little toot.
Holy smoke :shock: I think only one horn was working, but it was a LOT louder than before, so something is working!

Going down the boat in a bit to give her a bath and I think I'll take my can of PB Blaster with me and work on them some more. 8)

 

[johnsw]

I found in this last set that I took apart, that loose rust can also collect in the bottom of the bowl of the horn. The diaphragm doesn't actually flex much, so I can see how enough 'hard' rust collected in these things can be a problem.

Something to consider, as I just did it as a preventive thing myself this past weekend while I was doing some overdue cleanup. If your Ongaro horns have the 5 screws holding the works together, you can just loosen them by 1/16" - 1/8" and pull the back assembly away just enough for any water in the horn to drain out (don't remove the screws completely, as the cardboard gaskets can slip out and be cumbersome to put back in place while on the boat). Did it to mine and got an ounce or 2 out of each. Maybe some PB or WD40 flushed through them with the back loosened might help if you've got gunk accumulated at the bottom of the disk. Just remember to tighten the screws back up when you're done.

John

 

[TheOtherLine]

Well, my horns finally gave up the ghost. Took them apart and the rusted guts just crumbled in my hands.

After much searching and reading about some of the solutions on this forum, I decided to go with this horn.

http://www.stebel.it/stebel2009/product ... ia=nautica

I have these horns on a few of my motorcycles and I can tell you, they are VERY loud. Not quite a truck horn but loud nonetheless.

What I really like about this horn is the 1) It doesn't look like trumpets 2) the chamber is designed to isolate any water intrusion away from the working components.

We'll see....

 

[miky2884]

This is a project I have to dive into my horn didn't work last year, i guess im gonna start with the switch and go from there

 

[Bryan 2530]

Start with the horn. You need a new one.

TOL - How much for that horn??

 

[TheOtherLine]

TOL - How much for that horn??

$149 - Occasionally on ebay you can find them for $129 in chrome, not white. It's painted chrome, not really chrome.