Exhaust tube..good idea, bad idea or ??

[thunderroad]

My exhaust bellows has a pretty good rip in it. I know it won't sink the boat but it folds up kinda weird when the unit is down. I don't want to take a chance on any restriction so I'm gonna replace it. I remember it being a ***** to do last time, and don't really want to drop 50 bucks for the proper tool, so I started thinking about one of those open-ended tubes. What's the consensus? I've thumbed through a few books and see them listed, but I've never seen them shown as available for my unit. (Merc 160, SN 2497444). Maybe that's because it's so old...or maybe they're kind of universal. Any help would be appreciated.

 

[Haut Medoc]

Re: Exhaust tube..good idea, bad idea or ??

They are kind of universal, & it will install easily & work just fine......​

 

[thunderroad]

Re: Exhaust tube..good idea, bad idea or ??

Thanks. I think I'm gonna install one.

 

[starsnstripers]

Re: Exhaust tube..good idea, bad idea or ??

Open ended tube??? Whats that? Is it a tube that dont connect to the bellhousing or are you talking about a through transom exhaust? thanks

 

[lmannyr]

Re: Exhaust tube..good idea, bad idea or ??

I'm curious too. If it's just an easy fix, why do we all still have rubber bellows? Is there a limitation to this "tube?"

 

[wca_tim]

Re: Exhaust tube..good idea, bad idea or ??

Exhaust tube = GOOD!!!

only connects to the front of where bellows would, worth a few horsepower and MUCH easier to get on. Only difference is a little bit more noise, but not a lot. and can hear the exhaust gasses gurgling up around the drive when idling, but again not a big issue, have ot listen to notice...

 

[lmannyr]

Re: Exhaust tube..good idea, bad idea or ??

Can you post some pics of this install. Not sure until I see it. I'm a practical guy. I have a hard time with theory. Also, what is the price difference b/w the two?

THANKS!!!!

 

[wca_tim]

Re: Exhaust tube..good idea, bad idea or ??

sorry I don't have any pics off the top. It's pretty simple though. Just like most of an exhaust bellows, only the rear end is bigger around and not clamped. A little shorter too. The majority of the exhaust gas still goes through the hub, but it isn't sealed to it and so "leaks".

Hope that helps...

 

[lmannyr]

Re: Exhaust tube..good idea, bad idea or ??

Yes, it does help. I can picture it better now. Wonder if the some exhaust fumes returns back into the engine bay with this system.

 

[mkast]

Re: Exhaust tube..good idea, bad idea or ??

Wonder if the some exhaust fumes returns back into the engine bay with this system.

Only if the exhaust water does too!

 

[thunderroad]

Re: Exhaust tube..good idea, bad idea or ??

Here's a pic of a tube from the iboats parts pages. This particular one is pt no. 18-2760

 

[HT32BSX115]

Re: Exhaust tube..good idea, bad idea or ??

You can really do what ever you want with the exhaust bellows/tube.

When I had the Wonderful high tech OMC King Cobra on my boat it had the exhaust bellows missing for more than 10 years and no one noticed! My brother bought the boat new and it came with thru-hull exhaust. He had the engine rebuilt about 5 years after he got it (because in Calif you don't have to winterize boats) when the mechanic put the new engine in he also added a Y-pipe and thru prop exhaust. He didn't bother to put an exhaust bellows in the gimbal.

The only tell-tale sign was when at idle, all the exhaust bubbles came up closer to the transom instead of out the rear of the prop.

After I got the boat and looked in there I was shocked to see the exhaust bellows missing

I ordered a transom repair kit because I thought I'd need to replace both bellows' when I pulled the drive. When I installed the new exhaust bellows I was also surprised to see that the new exhaust bellows' have approx 1" slits that are supposed to be positioned down, presumably so they will drain properly.

OMC doesn't have a "tube" like the Mercury drives have. But Mercury suggests using the tube with higher HP engines to increase performance (or to get max performance)

That tube will never seal completely but it probably doesn't matter......


Cheers,


Rick

 

[captk]

Re: Exhaust tube..good idea, bad idea or ??

Merc originally used the tube in the,,, late 70s? They had some problems with the bellows expanding and pushing the u-joint bellows into the u-joints. Only used it a couple of years before they increased the size of the exhaust reliefs in the Transom assy. The tube can be used on any #1 it might be a little bit noisier.

 

[Mkos1980]

Re: Exhaust tube..good idea, bad idea or ??

I just replaced my origional bellow on my exhaust with a tube and man was it easy. 10 minutes tops. As others have stated it sounds louder at the dock and at idle, but underway I didnt notice a differance.

 

[lmannyr]

Re: Exhaust tube..good idea, bad idea or ??

Ok... there are two bellows then right? I thought if the bellows was cracked etc that it would leak. Fill me in..

Thanks..

 

[Bondo]

Re: Exhaust tube..good idea, bad idea or ??

Ok... there are two bellows then right?

Ayuh,..... 2 or 3 actually,......

1 for the Driveshaft,.....
1 for the Shift Cable,....
And,.....
Either 1 for the Exhaust, or the Tube.......
The Exhaust passage is Wet on both sides there anyways, so a Rip isn't going to Sink the Boat.....

I haven't found Any drawbacks to the Tube,..... Only Advantages.............

 

[Don S]

Re: Exhaust tube..good idea, bad idea or ??

I haven't found Any drawbacks to the Tube

Maybe there is one. If you like to put your boat up on the beach with the drive up, and there are waves rolling in, with the tube, there is nothing there to help the exhaust shutters wave after wave after wave.
With the bellows, the waves would have to try and climb thru all the passages to get to the exhaust Y. The tube is a funnel for the waves.

 

[Bondo]

Re: Exhaust tube..good idea, bad idea or ??

Maybe there is one.

Ayuh,........ Good Point,.........

 

[bhammer]

Re: Exhaust tube..good idea, bad idea or ??

I have one on my boat and I haven't had any issues with it. I do beach the boat and haven't had any issue there either but that is not to say I won't. I also have a closed cooling and that could help the fact.

 

[HT32BSX115]

Re: Exhaust tube..good idea, bad idea or ??

Actually that wouldn't make any difference. A closed system is the same exhaust wise from the elbows-out......The waves *could* still push water up into the y-tube ......closed system or not.....It would depend on how vigorous the waves are etc.....

It shouldn't be a problem if the shutters are still closing but if they were a little weak and/or were laying half open a wave hitting the 'tube' just right might slosh water high enough to make it 'over the hump' as it were......

I have one on my boat and I haven't had any issues with it. I do beach the boat and haven't had any issue there either but that is not to say I won't. I also have a closed cooling and that could help the fact.