Mercruiser Model 5.7/LX 350 MAG V-8 1996 Misc. Problems

[bordjord]

I recently purchased a 1996 Thunderbird Falcon with the above noted engine and a Mercruiser Model ALPHA ONE (GEN.II) 1996-1997 out-drive. The seller described the exhaust as "snub nose" not requiring exhaust bellows, and said to not life the trim while in the water because it will take on water. I am not a very experienced boater so I have not heard of anything like this, is this exhaust option possible?
Also, when removing the boat from the water and lifting the tilt, I noticed a slow leak of what appeared to be gear oil, from the "snub nose" exhaust, and the reservoir amount diminishing. While showing me the distributor cap and some electronics the owner removed the reservoir from the bracket and was moving it around while showing me different things, could this have caused a loose connection and slow leak or is the problem bigger?
Thanks for the help!
-New Boater

 

[dubs283]

Re: Mercruiser Model 5.7/LX 350 MAG V-8 1996 Misc. Problems

not sure what "snub nose" exhuast is

no mercruiser exhaust bellows is absolutely necessary, as long as the y-pipe seal is good and the bolts are tight

not trimming up the drive while underway?? causing it to take on water?? sounds like a bellows issue, can't be 100% though

as far as the gear lube monitor level going down, yeah that is a problem.

 

[Bifflefan]

Re: Mercruiser Model 5.7/LX 350 MAG V-8 1996 Misc. Problems

It sounds like he is talking about an exhaust tube instead of the bellows.
But again as stated it should not take on water if trimed up.
As for the oil you may have a seal leaking on the shaft. It may be time to invest in a manual and some friends that have mechanical prowis. or a good repair shop if your not comfortable doing some work on the drive.

 

[TilliamWe]

Re: Mercruiser Model 5.7/LX 350 MAG V-8 1996 Misc. Problems

Yep, it's an exhaust tube, and lots of Mercruisers have them. The boat should NOT take on any water through the exhaust tube, ever. Period. If it does, there is something wrong.

The oil leak could be caused by the reservoir tube's fitting through the transom. It's an annoying problem at best, since that fitting is very hard to reach.

 

[Don S]

Re: Mercruiser Model 5.7/LX 350 MAG V-8 1996 Misc. Problems

Before you put it in the water again, have a Merc tech have a look at it. I think you have bought some problems because you had no idea what to look for, and trying to find out what the previous owne did and what you need to do may take a long time, where a Merc tech can pull the drive and look things over in an hour and give you a good idea of what you REALLY have and don't have, and what your problems may be.
You could also pull the outdrive and do some picture taking/posting here and maybe we can help figure out the reason. You also need to winterize the engine so the block and manifolds don't freeze and crack, or you won't have anything.
I have never heard of "snub nose" exhaust myself, and I have been a marine tech for way too many years.

 

[bordjord]

Re: Mercruiser Model 5.7/LX 350 MAG V-8 1996 Misc. Problems

Thanks for the help. After some further investigation I realized this is an exhaust tube. I have the trim completely up as the boat is on trailer, I guess I am wondering how the boat doesnt take on water if I were to lift the trim while submerged, the tube is exposed. Also, the gear leak was not coming from the tub but below the tube, I'm assuming down the transom and dripping out below the exhaust tube. If it is a leak in the through transom connect, or any leak for that matter, does it have to be fixed to winterize the engine?
Thanks Again!

 

[TilliamWe]

Re: Mercruiser Model 5.7/LX 350 MAG V-8 1996 Misc. Problems

... I guess I am wondering how the boat doesnt take on water if I were to lift the trim while submerged, the tube is exposed...

Physics. It's called the "static line." Quite simply, the water inside the exhaust system will remain at the same level as the lake, more or less. Kind of like the trap on your sink drain? Water reversion is one reason that the exhaust manfolds have "risers" on them, and "flappers/"shutters" in the y-pipe.