1989 4.3LX Vibration Problem

[RobOp]

I have a 1989 Sea Ray 280 Sundancer with twin 4.3 LX sterndrives, the starboard engine was replaced with a new Mercruiser longblock reman in Sep 2010

Original engine - SN# 0C608246
Longblock reman PN# 14149R5 SN#90101845

I bought the boat in November and was told the new engine had about 10 hours on it since it was replaced. (it is now out of warranty)

Although I can't detect a great deal of difference in vibration levels between the engines, the new engine has had the following failures in the two hours of run time since I've owned the boat:

broken three heat exchanger holddown clamps
the alternator has failed
the power steering pump has failed
the power steering oil cooler has failed
Harmonic balancer seal has failed twice

It seems the engine is tearing itself apart! I thought about replacing the harmonic balancer and put in another new seal but everywhere I look the harmonic balnacer is NLA (no longer available).

What should I try next?? Are these old pre-Vortex engines prone to these vibration issues?

 

[RogersJetboat454]

Re: 1989 4.3LX Vibration Problem

Well...

The balancer my be discontinued through Mercruiser (haven't checked), but any automotive balancer from that era engine that is a matching diameter should work just fine as a suitable replacement...

But...
Is the balancer showing signs of wobble at all... I.E. the elastomer band between the inner and outer iron bits of the balancer has broken or is breaking and the balancer is wobbling?

Other possiblitys...
The engine was never correctly aligned to the drive.
The Ujoints on the drive shaft are clapped out.
Something is wrong with the drive its self.
Removing the drive, and running the engine with either confirm or disprove an issue with the drive.

Other thoughts...
Is the engine misfiring on one or more cylinders? Are the plug wires correctly routed? When is the last time it's had a tune-up?
Has the vibration been going on since day 1? Worst case I could think of is who ever built the engine didn't time the balance shaft right, or some how omitted it...

 

[RobOp]

Re: 1989 4.3LX Vibration Problem

Thanks for the reply.

The balancer looks fine, it seems to be in good shape.

The only way I can tell there is a problem is the damage that is being done when out cruising. I only have about 2 hours of cruising time on the boat so far. Even at cruise power I can put a foot on each engine and it's hard to tell a difference in vibration.

This era of engine (1989) does not have a balance shaft.

Can a misalignment to the drive cause a vibration? The engine was changed in Sep 2010, I wonder if the knuckle-head that changed it properly aligned the drive to the engine?

 

[RobOp]

Re: 1989 4.3LX Vibration Problem

Removing the drive, and running the engine with either confirm or disprove an issue with the drive.

How do I run the engine without the drive on? The outdrive provides the water to cool the heat exchanger. (FWC)

Pulley seem to be lined up fine, per my eye balls.

As I've said before this vibration is not obvious, the engine sounds fine, seems to run fine. I can run the engine without the drive engaged and it seems smooth enough. I make comparisons between the port and starboard engines and I'm not sure I can tell a difference. I don't know what removing the drive and running the engine will accomplish? I will have a drive service performed at the shop and have them check the alignment and U-Joint.

The reason I suspect vibration is because of all the breakage and failures I am experiencing in a very short period of time. It's like the stupid engine is trying to destroy itself...

PS - I forgot to mention the power steering bracket has also broken.

 

[starsnstripers]

Re: 1989 4.3LX Vibration Problem

If it's vibrating that much to break all this stuff you'd know it. You can take off the drive and hook a hose to the intake hose that connects to your tanson assy. Pull the hose off at the transom assy and connect the garden hose to it. While you have the drive off get an alignment tool and check it. The drive still turns the upper out of gear. By running it without the drive is to tell if it is smoother and to check your alignment. Also im not sure but food for thought, did you use the old flywheels? not sure if the balance may have been external on the old and internal on the new. Someone here may elaborate on that. Try tuning the engine over with ignition shut off and eyeball the balencer to see it it's wobbling.

 

[RobOp]

Re: 1989 4.3LX Vibration Problem

The balancer seems to be running true at idle and at 1000 and 1500 rpm. I agree that excessive vibration should be obvious with all this stuff breaking! But it is not! This is driving me crazy! Is there an instrument I can get my hands on to get a quantative measure of the vibration? Then I could get a true comparison between the two engines.

I think I'm going to buy the auto equivalent balancer and give that a try.

Stay tuned...

 

[Bondo]

Re: 1989 4.3LX Vibration Problem

I think I'm going to buy the auto equivalent balancer and give that a try.

Ayuh,... That could be alot work, 'n money fer Nothin'...

What does the Prop look like on this drive,..??

 

[RobOp]

Re: 1989 4.3LX Vibration Problem

The prop isn't new and pretty but there is no damage. I've had bent props before on other boats and you can definitely "feel" it.

The really maddening thing about this problem is that I don't feel or hear anything unusual, instead of doing things and looking for the vibration to stop, I'm trying to do things and hope the damage stops!

The two biggest indicators that I still have a problem is breaking heat exchanger clamps and blowing harmonic balancer seals.

My fear is that the problem is the engine itself, replacing it now could be alot work, 'n money fer Nothin'...

I am trying to eliminate all other possibilities before I get to that point.

The boat is currently in the water, my thinking is: I can replace the harmonic balancer myself (I'm getting pretty good at removing it and putting it back on unfortunately). After that I'll haul the boat and have the shop service the drives and check alignment.

Any ideas on what else to check or do are greatly appreciated.

 

[riskibusiness]

Re: 1989 4.3LX Vibration Problem

I have a good friend of mine who is a G.M. service mechanic. He has told me many times theat the 4.3 has exsissive vibration anyway

 

[RobOp]

Re: 1989 4.3LX Vibration Problem

Update from the Christmas weekend:

I don't think I have a vibration problem, the clamp that was breaking was not nearly substantial enough for the job, I have replaced it with a heavy duty hose clamp and now no problems there.

The Harmonic Balancer seal continues to be a problem; I put a new harmonic balancer on it and monitored it for vibration, about the same as before as far as I can tell. I had a professional mechanic / engine builder look at it and he said the vibration level was normal.

I believe the reason for all the seal problems is the timing cover was not aligned properly by Mercruiser in the reman process. The engine manual calls for the use of an alignment tool (GM# EN-48869) to make sure the seal is centered, the manual warns that this is NECESSARY or oil leaks are likely to occur.

I am ordering this alignment tool and will remove and re-install the timing chain cover.

Hopefully all the other failures were coincidence. Wish me luck.

 

[dubs283]

Re: 1989 4.3LX Vibration Problem

the '89 vintage 4.3L blocks are non-balance shaft

mercruiser equipped the motors with fluid motor mounts to help alleviate engine vibration

it is quite possible that one or both or all four mounts (four is including both motors) have failed given the vintage of the boat/motors and no mention of the mounts being inspected/replaced - best to remove both drives, check engine alignments

don't worry about running the motors without the drives, they will be okay for up to a minute without water

keep in mind that a FULL tune-up including filters and a fuel system inspection/replacement of faulty components does wonders for engine runnabilty

 

[RobOp]

Re: 1989 4.3LX Vibration Problem

How can I tell if a motor mount has failed? What do I look for?

 

[dubs283]

Re: 1989 4.3LX Vibration Problem

How can I tell if a motor mount has failed? What do I look for?

the merc motor mounts have two wires on either side of the mount, if the wires are taut (top to bottom) they are good, if there is slack they are failing or have failed

my guess is they have failed

your best bet at this point, replace both mounts (nla) and long blocks with new (updated) 4.3L engines...

and as long as you are going with new long blocks and mounts, find yourself some new 5.7's and just cruise about