Help with engine noise ( Vid) Merc. 3.0 lx

[fishinrado]

Hi All, I have a 97 Mercruiser 3.0 LX that came on a Bayliner Capris I've owned for ( this summer) 3 years. A Relative commented last summer ( previous same boat owner) that he thought it was vibrating rather loudly. Engine seems in great shape with relatively low hours for the year. I replaced the lower unit seals ( was getting gear lube weeping out) water pump prop etc. and have not had the problem return. Runs at correct temp and oil pressure. I had it out yesterday and the odd vibration is still there although the boat runs great tubing, waterboarding and cruising. I have posted a YouTube after we got home so please give me your thoughts. Can not hear the sound at lower RPM's and it makes no difference in or out gear. You'll hear the Raspy vibration in the Vid once the engine is revved!
Thanks........

 

[thumpar]

Try removing the drive and put the hose in the bellhousing to see if it is coming from the engine or drive.

 

[Bt Doctur]

My Goodness, that is loud, it will get louder the more you have the drive raised.And you will explode the U joints
If it makes that noise when level you have bad U joints getting ready to explode

 

[fishinrado]

Level as in Lowered in the correct position? Yes the Vid was taken with the Drive lowered down almost to ground. Yea I did some reading and I see the u-joints spin in or out of gear correct? I have never started the boat with drive up so guess this is just normal wear and tear for the age? I imagine there are some good write-ups here so I'll pull the lower unit and go from there. I'm a pretty good DIY er so I'll be tackling it myself. Thanks for these and any other replies!

 

[thumpar]

If it is the u-joints is it pretty easy and cheap to fix.

 

[fishinrado]

Any way of Confirming ( tests etc ) this is the issue? Thanks! Oh and a good source of parts required and place to purchase? I imagine some seals are going to need to be re-done as well?

 

[Bt Doctur]

Level as in Lowered in the correct position? Yes the Vid was taken with the Drive lowered down almost to ground.

No friggin way that drive is down all the way, remove the trim cylinders and it will drop another 10 inches.
With the motor running everything spins including the gears in the lower unit. In neutral the only thing not spinning is the prop shaft.

 

[Bt Doctur]

Now this is a vibration problem

 

[Bt Doctur]

this is what is called "level" or down all the way.

 

[fishinrado]

Yea, hahahha ok. I just realized it was not 100% way down. I'll recheck it later but the boat was on the driveway (inclined) bow facing downhill so it was close!
Nice Knot.........reminds me of when I was a kid , back east, fishing with and open reel. My old man used to throw a nutty.............

 

[Bt Doctur]

A tip ,should you be in that situation of not completely lowering a drive 2 8 x 8 landscaping ties with an angle cut to drive up on.
Just remember to raise the drive BEFORE driving off the ties.

 

[Fun Times]

On some boats you will have to lower the front of the trailer as much as you can to run them properly on the trailer even if that means using a floor jack and raising the swing away trailer jack out of the way. Then as you lower the stern drive, be carful not to hit the back of trailer.

The height that the drive is at now on the video does appear to be a factor of the noise at higher RPM and is almost normal....That mentioned, it still seems a bit louder than normal. If you really can hear the noise like that while on the water and you know for sure the drive is "all" the way down, then you definitely still have a problem.

Either way the stern drive has to come off the boat for inspection at the very least...Like mentioned above by thumper, remove the drive and re-run the engine just to be sure of the noise goes away.

Good luck.

 

[fishinrado]

Yea even on the water with the drive down it sounds the same. Sounds the same in gear or not but only at Higher RPM in the water as well . Of course when your cruising you really can't hear it but you sure can feel the vibration. Almost like you set a metal can on an engine while running and it shimmies back and forth. I guess I have been lucky as I've made 20 or more trips to the lake and cruised all day, waterboarded etc with no issues. It was only after yesterdays outing I decided that yea maybe it really doesn't sound right after all. Overall we have been stoked on the boat and motor ( bought it for a reasonable 5k three summers ago) and am definitely all about doing whatever it takes to make it right. Only money we have spent is the lower unit seal kit, new speakers and a WB Tower.
knock, knock, knock.....

 

[fishrdan]

Did you remove the whole drive while replacing the lower unit seals, or just drop the lower unit?

My thought was U-joints like others have noted, so I would remove the whole drive and inspect the U-joints and gimble bearing. IF.... a U-joint lets-go it's going to tear up lots of expensive things.... I wouldn't run the engine again until the U-joints are inspected

 

[fishinrado]

Hey thanks! When I did the seals I just dropped the Lower Unit. Been a few seasons so I'll have to find a good write-up on removing both sections. I'm assuming its a two part process and you don't just remove the Whole Drive Unit?
No I'll not start it again but will pull it apart tom. and post..........

 

[fishinrado]

So I just found a good U-tube and it appears all you do is remove the trim cylinder rods and then it's 6 bolts to take the whole lower drive off. From the video it shows the drive shaft comes out that runs through the bellows and has the shaft and the U-joint attached. Looks pretty straightforward and looks like you can inspect the gimble bearing as well at that point?
Thanks!

 

[thumpar]

Yes, you remove the whole drive as a unit as you described. It is really easy. I would recommend you do it at least every other year for impeller change, lube, inspection and alignment.

 

[Fun Times]

Also being an Alpha stern drive, be sure to put the shifter into forward gear or you could do some damage while removing/re-installing the drive.

You'll need a mercruiser engine alignment tool before reinstalling the drive. Be sure to grease the engine coupler a few times by adding grease to the engine alignment tool bar. http://www.ebay.com/sch/i.html?_nkw=...alignment+tool

The stern drive gasket installation kit you'll need is Merc part number 27-94996Q2 http://www.ebay.com/sch/i.html?_from...996Q2&_sacat=0

And 92-8M0071841 U joint & Gimbal bearing/Engine coupler & spline to do it correctly. http://www.ebay.com/itm/Mercruiser-U...114211&vxp=mtr

http://www.mercruiserparts.com/selec...+++1996%2D1997

 

[fishinrado]

Hey great! Thanks for all the parts list! Yes I had read "put the drive all the way in forward gear" before dismantling as it aligns everything prior to dis-assembly.
The alignment tool I was just about to inquire about so thanks again!

 

[fishinrado]

No Title

Well just pulled off the drive, very simple, not much the untrained eye can see at this point. Gimble bearing solid and smooth. All bellows look hardly aged. U-joints seem to have zero play but is there a good way to test them? Here are a few pics at this point. Pic 1 , where I'm pointing , is where the hose should go to start and see if I still have the vibration. Really the only thing I noticed is that the 6 bolts holding on the Drive were not super tight and came off, with what seemed to be, too little effort.
***anyone recognize the u-joint number or yellow band color? Could not find a pic of it on the net so wondering if these are original or not?