Covverting to Thru-Hull Exhaust?

[militaryboating]

I have a 1989 Galaxie w/ 5.0 I/O and an aplha one outdrive (with a thru prop exhaust). I saw one of my buddies boats on the lake a couple of weeks ago, but he had a thru hull exhaust (dont know what size motor). His boat sounded great, deep rumble at idle and a nice roar on plane. My question is.. Is it possible to convert my exhaust to a thru hull without alot of headache? If i did would it hurt my motor? Would it sound good, like I said I dont know what size motor he had, forgot to ask.

Thanks guys

 

[arks]

Re: Covverting to Thru-Hull Exhaust?

Without a lot of headache?
I guess that depends on what you consider 'a lot'.
I installed a switchable exhaust on my previous boat- a 23 foot cuddy with a Merc 260. It sounded great. Hardest part was cutting 2 BIG holes thru the fiberglass. Measure twice, cut once.....
Before starting you've got to make sure the top of the exhaust risers are at LEAST 2" above the waterline to prevent water reversion. More is better, of course. It may involve replacing the risers or adding spacers.
Unless you're handy with tools, I think this is a job best done by a professional. Just my opinion.

 

[HT32BSX115]

Re: Covverting to Thru-Hull Exhaust?

Howdy,

Is it possible to convert my exhaust to a thru hull without alot of headache?

Yes, but to do it right, you need to remove the engine and follow the Mercury/Mercruiser Installation manual.

If i did would it hurt my motor?

No, see above....

Would it sound good

Only to you. Most everyone else would not like it (and if you do not use rather expensive mufflers), neither would the "Noise Cops".

I had thru-hull exhaust in my 87 Four Winns Liberator (With Capts Call diverters) before I pulled the (high tech) OMC 460 King Cobra. When I replaced it with the Mercruiser 454/Bravo, I DID not reconnect them and am glad I didn't!!


Do a search on this forum for "Thru Hull Exhaust" and you'll find multiple threads on the subject.


It's almost as popular as "What kind of oil should I use?"


Regards,


Rick

 

[jtmarten]

Re: Covverting to Thru-Hull Exhaust?

I had thru-hulls on my 454 jetboat. Loved them! Loud, but not obnoxious. I was dtill running logs/snails.

I'm guessing by your sound description your buddy prob has a big block.

It's easy and relatively inexpensive if you want to convert thru-prop to thru-hull; just tips, hoses, and caps for the Y pipe.

A little more complicated to install a switchable exhaust, which I'd recommend. Will give you the best of both worlds; quiet for around the marina/docks, loud and open when out cruising. Most switchables will run $550-800 for a single engine application.

 

[militaryboating]

Re: Covverting to Thru-Hull Exhaust?

where does the tips need to sit in comparison to the water? should they sit in the water when the boat is at idle, and above when on plane? or should they be above water all the time? does anyone have pictures of the process?

 

[Bondo]

Re: Covverting to Thru-Hull Exhaust?

should they sit in the water when the boat is at idle, and above when on plane?

Ayuh,.... Just below waterline is Quieter at idle.... The faster you go, the Louder it gets...

 

[v8power]

Re: Covverting to Thru-Hull Exhaust?

I converted my 1980 cobalt w/260 merc v-8 to thru hulls. I love it and it sounds great, Just a couple weeks ago I got stopped by A ohio watercraft officer for a spot safety inspection, And he complimented me on how good my boat sounds, the install wasnt to bad, except I had to switch from log manifolds to center riser manifolds, I bought rubber caps for the original Y-pipe so I didnt have to pull the engine, cuz I wanted to leave the Y-pipe in so if I wanted to switch back I could. My tips are a couple inches above the water line at idle and its not really that loud. I have not had anyone complain about the sound at the 2 marinas i frequent. Just compliments. So Id suggest that if you like it, then do it. Its only dollars and labor.

 

[militaryboating]

Re: Covverting to Thru-Hull Exhaust?

I converted my 1980 cobalt w/260 merc v-8 to thru hulls. I love it and it sounds great, Just a couple weeks ago I got stopped by A ohio watercraft officer for a spot safety inspection, And he complimented me on how good my boat sounds, the install wasnt to bad, except I had to switch from log manifolds to center riser manifolds, I bought rubber caps for the original Y-pipe so I didnt have to pull the engine, cuz I wanted to leave the Y-pipe in so if I wanted to switch back I could. My tips are a couple inches above the water line at idle and its not really that loud. I have not had anyone complain about the sound at the 2 marinas i frequent. Just compliments. So Id suggest that if you like it, then do it. Its only dollars and labor.

makes me feel alot better. i was worried about it being to loud, or just abnoxious loud. about how much did it cost for everything you needed? would still love some pictures of the process. i hate jumping into something and realize i dont have everything i need.

 

[Philster]

Re: Covverting to Thru-Hull Exhaust?

Tips: Few hundred bucks?

Exhaust hose: 100 bucks?

Maybe some pipe: 250?

Somewhere around 500 bucks.

As noted, there is a drop need from the riser down through the exhaust hose/pipe and then out the transom.

New risks: Water reversion, if the app is done wrong. Mercruiser setups sometimes require the transom holes to be very exact. Sometimes they are practically the same on all boats. You sound like you want 'em above the water line so you hear 'em all the time.

So far, the last two guys with boats over 15 years old that I helped cut holes in the transom went from "Yay, a new exhaust" to "What? My transom is wet and rotting?"

I have waterlift mufflers w/ a thru hull setup and thought about ripping them out, but love them. Plane-jane open thru hull = novelty. Wears on you. I had load duals on my truck, and replaced them, too.

My boat has a growl/tone, but it isn't obnoxious like a regular thru-hull, and I love my truck, too, with just a simple Magnaflow muffler = nice tone. If you go 'thru hull', consider mufflers please. Nothing wrong with a growl/tone, but an obnoxious open exhaust is ...well.... obnoxious.

 

[180shabah]

Re: Covverting to Thru-Hull Exhaust?

Before starting you've got to make sure the top of the exhaust risers are at LEAST 2" above the waterline to prevent water reversion.

that is 12 inches, not 2.

 

[jtmarten]

Re: Covverting to Thru-Hull Exhaust?

So far, the last two guys with boats over 15 years old that I helped cut holes in the transom went from "Yay, a new exhaust" to "What? My transom is wet and rotting?"

+1
Especially if you want them below the waterline. Above the waterline they still need to be properly sealed or you'll have problems in the future.

If you don't go with switchable exhaust, there are switchable mufflers too, quite a bit cheaper than a full switchable exhaust.

 

[180shabah]

Re: Covverting to Thru-Hull Exhaust?

there are switchable mufflers too

who makes these???

 

[jtmarten]

Re: Covverting to Thru-Hull Exhaust?

There are several mfg/distributors. I can't remember specific mfgs. I did a google search several months ago and found quite a few.

 

[militaryboating]

Re: Covverting to Thru-Hull Exhaust?

So far, the last two guys with boats over 15 years old that I helped cut holes in the transom went from "Yay, a new exhaust" to "What? My transom is wet and rotting?"

how does the transom rot? its fiberglass just like the hull of the boat. i think i would love the sound, but i think the easiest place to mount it would be under my swim platform, although i could mount it to the side of the boat above the water but that seems like alot more headache. would it be, i think i would like them better in the water at idle, but if its going to ruin my boat i dont want to do it at all.

 

[Philster]

Re: Covverting to Thru-Hull Exhaust?

Wasn't claiming you were going to rot the transom... was just letting you know that old boats sometimes wind up looking old when you cut into them. We got the 4" hole saw past the gel and into the wood and it wasn't good.

 

[dirtyoldman]

Re: Covverting to Thru-Hull Exhaust?

Where are you? It's illegal now in Kansas. Even running a boat with captains call and not using it is illegal.

 

[haulnazz15]

Re: Covverting to Thru-Hull Exhaust?

how does the transom rot? its fiberglass just like the hull of the boat.

Unless you have a premium brand boat (like a Cobalt) built within the past few years, your transom is not made of fiberglass. It is 3/4 -1 1/2" plywood sandwhiched between the fiberglass outer hull and an inner fiberglass skin. When you drill holes in the transom, you introduce a way for water to get to the wood inside. Transom rot occurs in areas around the bilge drain and the outdrive if water intrusion occurs. Cutting holes for you exhaust makes another point of entry for water.

Edit: Just saw you had an '89 Galaxie, you definitely don't have a composite transom, so you are susceptible to transom rot.

 

[HT32BSX115]

Re: Covverting to Thru-Hull Exhaust?

i think i would like them better in the water at idle, but if its going to ruin my boat i dont want to do it at all.

Installing Capt's Call doesn't ROT the transom, cutting the 4" holes DISCOVERS it if it's there!


I had Capts Call on my Liberator when I had the 460 installed.

Every time I switched it ON, everyone else in the boat would say "TURN IT OFF TURN IT OFF!!!!!"

When I installed the 454 Bravo, I left the Capts Call in the box on the floor.....


Here's what Kansas currently says about boat engine noise..... It appears that you could have Capts Call only if it was available when the boat was new depending on year model etc.... (I just LOVE the GOVT!!)

 

[militaryboating]

Re: Covverting to Thru-Hull Exhaust?

Unless you have a premium brand boat (like a Cobalt) built within the past few years, your transom is not made of fiberglass. It is 3/4 -1 1/2" plywood sandwhiched between the fiberglass outer hull and an inner fiberglass skin. When you drill holes in the transom, you introduce a way for water to get to the wood inside. Transom rot occurs in areas around the bilge drain and the outdrive if water intrusion occurs. Cutting holes for you exhaust makes another point of entry for water.

Edit: Just saw you had an '89 Galaxie, you definitely don't have a composite transom, so you are susceptible to transom rot.

O... Learn something new everyday. So if I cut the holes and sealed them up, would the heat effect the seal? How hot would the tips actually get, because I know water is pushed throught the exhaust. would they get hot enough to hurt the faberglass, or the sealent (depending on what kind i get?)

 

[HT32BSX115]

Re: Covverting to Thru-Hull Exhaust?

O... Learn something new everyday. So if I cut the holes and sealed them up, would the heat effect the seal? How hot would the tips actually get, because I know water is pushed throught the exhaust. would they get hot enough to hurt the faberglass, or the sealent (depending on what kind i get?)

It's not a problem. There's a fair amount of water that goes through the exhaust so the temp doesn't get all that close to even the boiling-point of water....