4.3l merc with vibration and the dreaded ticking noise

[rock doc]

Hi there,

This seems to be a very popular foum. I noticed there are over 200 people currently viewing this forum when I posted this cry for help. I recently acquired the boat and I am trying to get the motor to run smoothly. It has a rebuild in it that is approx 2 years old and low hours.

I have had a merc mechanic out for a test drive and he seems a little stumped. The motor seems off balance and is ticking. The ticking is constant and varies with rpm. I have checked the oil level, presure, engine temp ect. and it seems fine. The ticking is coming from the front of the motor. Not really a lifter noise?? The boat seems to vibrate a little too much and the mechanic is wondering if the rebuilt motor was properly balanced.

We pulled the drive and the gimble and u-joints are fine. The carb was cleaned and the fuel system was flushed. I checked the plugs and 2 seemed to be running a little rich (#1 &6). I replaced the plugs. The timing is fine and is advancing with increasing rpm. All plugs are firing.

My next steps are:
1) pull off the accessory belts to check the raw water pump
2) start pulling wires one at a time to check the conn rods; and
3) compression test

If all else fails, we'll have to pull the valve covers. Is there anything else I shoud be considering?

 

[littlebookworm]

Re: 4.3l merc with vibration and the dreaded ticking noise

I'd suggest you reverse the order you plan on checking things - check compression first. But before you do that, I suggest you check the fuel pump, assuming it's a mechanical pump. I've seen situations on auto pumps where the wrong fuel pump and/or push rod (if there is one) was used. This leads to erratic fuel delivery, a ticking sound, and low power. Sound familiar? Hope this helps. Hy

 

[Pete104]

Re: 4.3l merc with vibration and the dreaded ticking noise

Which 4.3? Rebuilt when? By who, your nieghbor or a cousin!

 

[rock doc]

Re: 4.3l merc with vibration and the dreaded ticking noise

My 4.3l has an electric fuel pump. It is definately worth checking though.

Thanks for the advice littlebookworm.

 

[rock doc]

Re: 4.3l merc with vibration and the dreaded ticking noise

I just finished pulling the drive belts off the water pump and alternator (all I had time for). The noise appears to be coming from the crank/harmonic balancer/belt drive cog. The motor does vibrate pretty badly too. Can these balancers go off balance? Oddly, the the ticking noise gets louder once the motor is up to operating temp. Does that suggest the crank is bad as opposed to the balancer? Is the balancer hard to take off?

Another discouraging finding wasthat someone had replaced one of the 3 bolts holding the belt drive cog to the balancer was a coarse thread. Seems someone stripped the threads and took a short cut.

 

[Bondo]

Re: 4.3l merc with vibration and the dreaded ticking noise

Is the balancer hard to take off?

Ayuh,... Not bad if ya got space for the Puller needed...

 

[rock doc]

Re: 4.3l merc with vibration and the dreaded ticking noise

I took the outer belt drive pulley that bolts up to the blanacer and this is what I found :facepalm:

I am assuming that there is not supposed to be oil behind the belt drive pulley.

 

[Bt Doctur]

Re: 4.3l merc with vibration and the dreaded ticking noise

aside from that ,it uses 4 bolts for the pully, the threads for the nose bolt arent there either

 

[Bondo]

Re: 4.3l merc with vibration and the dreaded ticking noise

I took the outer belt drive pulley that bolts up to the blanacer and this is what I found :facepalm:

I am assuming that there is not supposed to be oil behind the belt drive pulley. View attachment 101701

Ayuh,... That's odd....

Looks Bad, not so much the bit of oil,...
But All the threads are boogered up....

 

[Bt Doctur]

Re: 4.3l merc with vibration and the dreaded ticking noise

seems that this rebuilder shouldnt be rebuilding anything mechanical. looks like the balancer was just hammered on.

 

[rock doc]

Re: 4.3l merc with vibration and the dreaded ticking noise

So the oil isn't necassarily a bad thing? I'm hoping it is just the balancer that is bad.

 

[90stingray]

Re: 4.3l merc with vibration and the dreaded ticking noise

What year motor are we talking here?

 

[rock doc]

Re: 4.3l merc with vibration and the dreaded ticking noise

It is a rebuilt 4.3l merc (GM) with a 2 barrel carb and an an alpha 1. It is installed in 1990 Larson. Raw water cooled. I'll go get the serial #now.

 

[rock doc]

Re: 4.3l merc with vibration and the dreaded ticking noise

B2C
11.11.88
GM6269732 214


I assume the block is an 1988?

 

[Bt Doctur]

Re: 4.3l merc with vibration and the dreaded ticking noise

we dont know if its a balance motor or a regular motor. how many bolts does the intake manifiold have?
what about the threads for the crankshaft, you really cant hammer one on.

 

[rock doc]

Re: 4.3l merc with vibration and the dreaded ticking noise

I'm not sure about the threads - could this be evidence that the balancer either was not matched to the motor or off balance? The balancer did not feel loose but maybe when it was spinning it was starting to pull the threads.

I'll check on the motor tonight. I know the past owner told me which one it is, but I can't recall off hand. He is goinf to call me this weekend to discuss this whole mess. I hope he helps me out somehow.

 

[rock doc]

Re: 4.3l merc with vibration and the dreaded ticking noise

I found this on another site...thought it may be of interest to some folks. I'm goinf to have a look tonight and see if I can figure this out.

1986 - 1992, 14149R5
Non-balance shaft, mechanical fuel pump, roller camshaft, one piece rear seal.
A. Easily identified by metal 10 bolt short front cover similar to 5.7L.
B. Some nQn-balance shaft engines were produced without a manual fuel pump. This engine will fit either application with a fuel pump cover if manual fuel pump is not needed. C. All 12 intake manifold bolts are at 90 degree angle to cylinder head machined surface.

1993-1995 806347R5
Balance shaft, no mechanical fuel pump, roller camshaft one piece rear seal.
A. Easily identified by tall metal 10 bolt front cover different from 5.7L.
B. All 12 intake manifold bolts are at 90 degree angle to cylinder head machined surface.

1996- 1998 807736R5
Balance shaft, no mechanical fuel pump, roller camshaft, one piece rear seal, "Vortech" cylinder heads with rocker ball & stud valve train.
Note:
A. Vortech heads are easily identified by only 2 bolts per corner of intake manifold for a total of 8.
B. The older crankshafts rear flange are 0.123" longer and have a small pilot bushing hole in back.
C. Plastic 6 bolt front cover.

1999- 2002 864256A1
Balance shaft, no mechanical fuel pump, roller camshaft, one piece rear seal, "Vortech" cylinder heads with roller rocker arm valve train.
A. Vortech heads are easily identified by only 2 bolts per corner of intake manifold for a total of 8.
B. The cylinder head actually went to the "roller rocker arm" in 2000. Mercury Remanufacturing has elected to change coverage to coincide with the 1998/1999 crankshaft change as the customer would have to change flywheels to coincide with the crankshaft used. The 1999 customers will actually get a product improvement with the roller rocker arms and will not have to make any changes to their current parts.
C. The crankshaft has a 0.123" shorter rear flange and larger pilot bushing than previous versions.
D. Plastic 6 bolt front cover.

 

[rock doc]

Re: 4.3l merc with vibration and the dreaded ticking noise

How big a job is it to replace the crank seal?