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Air horns

Posted: Thu Jun 11, 2015 7:20 pm
by javalin390
Since the purchase of my 37' I am finding all the things that are wrong with it, as mentioned in some previous posts. One thing I found was the horns do not work. I have fixed a few items so far, like the air hoses to each horn were kinked shut ! One of the previous owners had tried to fix it before and was unsuccessful, and had mounted a single cylinder, piston type 12 volt air compressor in the dashboard up on the flybridge. I had to straighten out the wiring, as it was all butchered up too. once done, the piston type air compressor would not produce enough air ( volume ) to blow the horns ( it has 4 trumpets, two on each side of the bridge ) All 4 are plumbed together. I tried to just hook up two, but the volume of air was still not sufficient. Thinking that a piston style air compressor probably needs a storage air tank, I instead bought a new WoLo vane style air pump, commonly used on cars/pick up trucks ( like the Dixie horn on the Dukes of Hazzard car ) It was a 28 PSI pump, but yet again, still not enough volume to blow the horns. The only thing I can think of is that these horns are of the type that are used on semi trucks & trains, that require 90-120 psi to operate. I cannot find a brand name on the trumpets, or an operating pressure number. Only "23 L" is stamped on the chrome base . Are these factory Marinette horns ? Anybody run into this before. A brand new WoLo set up with trumpets & matching compressor will cost about $200 -300, so if I want to replace all 4 trumpets, I will need two complete kits at a cost of more than $500 !! I'd rather not "blow" that kinda money ! Help.

Re: Air horns

Posted: Fri Jun 12, 2015 9:26 am
by collins69s
Just wondering, did you follow the air lines all the way from the comp to the horns? Do they make any sound at all? Maybe you'll find a surprise..

Re: Air horns

Posted: Fri Jun 12, 2015 12:12 pm
by barkleydave
Mine at one time hardly made any sound at all... further investigation...MUD DOBBERS! Cleaned out horns and away they went.

Re: Air horns

Posted: Fri Jun 12, 2015 2:55 pm
by Rob
Those mud dobbers are a pain! On my 73, the air horns are Hadley's with a holding tank in the bilge. The air pump runs off the vacuum off the port carb (sounds like a valve knocking). I tested the horns with a small portable compressor first. The pump was putting out air but was not filling the tank. I put a small check valve in the air line after the pump and it fixed the problem.