Mercruiser exhaust: tube vs bellows

[imported_MORIVERRAT]

I'm running a 5.7 L EFI engine on an Alpha 1 outdrive. What are the pros/ cons to using an exhaust tube vs the bellows?

 

[Bondo]

Re: Mercruiser exhaust: tube vs bellows

Using the Tube is a No Brainer if you've Ever tried to Install the Bellows..............

I don't know of Any down-side to the Tube.......

 

[FreeBeeTony]

Re: Mercruiser exhaust: tube vs bellows

I installed the tube this year.............very easy to install.

Maybe be a bit louder than the bellows............

 

[180shabah]

Re: Mercruiser exhaust: tube vs bellows

How does the tube work??

I asume it is not flexible, so how does it allow for drive motion??

 

[Bondo]

Re: Mercruiser exhaust: tube vs bellows

It Clamps onto the Bellhousing side,+ Gloves into the Outdrive side..........

When the Outdrive is in the Down position anyways.......

 

[FreeBeeTony]

Re: Mercruiser exhaust: tube vs bellows

It is flexible............made out of rubber.

 

[WillyBWright]

Re: Mercruiser exhaust: tube vs bellows

It's the equivalent of increasing the exhaust pipe size on a car. The engine breathes a little easier, and you'll probably pick-up a few Hp. But I doubt it will be noticable. It will make a tad more noise.

 

[180shabah]

Re: Mercruiser exhaust: tube vs bellows

So, it is a worthwhile change if you are replacing the bellows anyway. Guess I, will wait, as I just did mine this spring, I should have a few years before I need to think about it.

 

[flashback]

Re: Mercruiser exhaust: tube vs bellows

I think the early drives only had the tube, the reason for bellows was probably to quiet the engine down a little more. I also would bet that a unit with bellows has a little more back pressure..

 

[Bondo]

Re: Mercruiser exhaust: tube vs bellows

Actually FB,.... Ya got it alittle Backwards,.....

The Tube is a Newer innovation,......

The Older drives all had the Bellows,.....

I'm not exactly Sure,......
But I believe that the Tube is Retro-fitable to the Older drives,........
Someday I might find out,.. As I'll Never install another Exhaust Bellows again.............

 

[flashback]

Re: Mercruiser exhaust: tube vs bellows

Well Bondo, your probably right, I have always been a little backwards anyway dd.. When I got my 79 210 scorpion about 3 years ago, It had the the tube on it so I thought or assumed (a bad thing) that it was stock.. in any case, I still like the tube.........dd And have a very Merry Christmas and happy new year...d

 

[Don S]

Re: Mercruiser exhaust: tube vs bellows

You guys don't even know why the tube was even started.
With the new higher HP efi and mpi engines, there was too much back pressure in the exhaust sytem going thru the drive. so Merc came up with this tube which allowed the excess exhaust gasses to escape BEFORE the drive.
It does make the engine a little louder but not a LOT.
The tube also keeps those extra exhaust gasses that are escaping, from being pushed down near the prop.
With an Alpha I or and Alpha I Gen II drive with and engine of less than 280 hp, the tube is not even necessary.
But it is easier for the DIYer to do since he doesn't usually have the tools to install the proper exhaust bellows on the drive.

 

[Bondo]

Re: Mercruiser exhaust: tube vs bellows

You guys don't even know why the tube was even started.

You're Absolutely Right Again Don,............d

I had No idea Why they were devoloped,........
I just know that they Work,+ are Better,+ Easier to install than the Bellows.......
And,.......
flashback's post tells me that they'll retrofit to the old Mod.1s as well................

 

[flashback]

Re: Mercruiser exhaust: tube vs bellows

I sorta figured it was because of back pressure, I just had the time line wrong.. d (oops there i go assuming again).. Thanks for the info Don..When I got my boat, it was in such bad shape I didn't think the previous owner did anything to it.. The drive is one from that period tho, It has a lifting hole in the casting on top of the drive. again I assume it is a lifting hole?

 

[imported_MORIVERRAT]

Re: Mercruiser exhaust: tube vs bellows

Thanks for all the good info and opinions, guys,
I'll be trying the tube next spring.

 

[Boomyal]

Re: Mercruiser exhaust: tube vs bellows

My friends '78 898 has the exhaust tube. Couldn't say whether or not it was OEM for that year

I'll have to check my '76 888. I haven't had occassion to look yet.

 

[pstorey]

Re: Mercruiser exhaust: tube vs bellows

I have a Bravo 2 and the exhaust bellows will not stay attached to the gimbal so installed an exhaust tube. My boat is a pleasure boat so I don't appreciate the extra noise. Any suggestions as to how to make the exhaust bellows work? Tried adhesive came off, no adhesive still came off. It seems as though the bellows should be about an inch longer. Any help is appreciated.

 

[indy440]

Re: Mercruiser exhaust: tube vs bellows

holy old post...

You might get better replies if you start a new thread? good luck either way!

 

[Bondo]

Re: Mercruiser exhaust: tube vs bellows

December 29th, 2006, 12:09 PM

Ayuh,... The archives are for readin',+ learnin',.... Not posting too....
This thread is 3 Years Old...

Start your Own thread pstory....

 

[gene8084]

Re: Mercruiser exhaust: tube vs bellows

...The drive is one from that period tho, It has a lifting hole in the casting on top of the drive. again I assume it is a lifting hole?

That hole was for the old manual tilt-up cable connection.​