4.3 LX engine clunking

egldvrbags

Petty Officer 2nd Class
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Sep 8, 2007
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1995 4.3 LX. I've owned this boat for 2 years, no probs, serviced each year w/ oil changes, lube, etc. Been using it this summer, no issues. Last week, the back of my boat lift broke and I found my boat doing a "wheelie." No visual damage to the boat and the water is deep enough the stern shouldn't have hit bottom, who knows?

After lowering the lift, I attempted to start the boat and the motor turned over very slowly, then just got the click from the starter selenoid. Seemed unusual as the battery is new. All accessories worked fine. Charged the battery and reattempted start. Got several selenoid clicks, then it cranked up.

Now, I have a steady engine clunking noise that I've never heard before. Oil is full and good oil pressure. Doesn't sound like it's a valve clicking.

I didn't take the boat out and have only let it idle.

Any ideas?? Just seems too coincidential w/ the boat lift breaking, but, remembering the Morton Salt jingle, "when it rains it pours."
 

Robj

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Re: 4.3 LX engine clunking

Wonder if you got water into a cylinder when the incident happened? Hydrolocked it, and when you did manage to get it to turn something gave? Just a WAG but based on your description that is what I think happened. When it did not want to turn, you should have pulled the plugs and checked for water. See what others have to say.

Good luck and hope your day gets better.

Rob.
 

egldvrbags

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Re: 4.3 LX engine clunking

Wonder if you got water into a cylinder when the incident happened? Hydrolocked it, and when you did manage to get it to turn something gave? Just a WAG but based on your description that is what I think happened. When it did not want to turn, you should have pulled the plugs and checked for water. See what others have to say.

Good luck and hope your day gets better.

Rob.

Rob,
Yeah, that thought crossed my mind. I'm more leaning towards that with the boat inclined w/ the bow about 2ft higher than the stern for possibly a week (this was the time between visits, so it could have been as short as a day, who knows) something in the engine wasn't lubricated properly.

It was floating in the water normally for about 5 mins before I attempted to start it, so it wasn't still in an incline.

Maybe a main bearing????

Thanks to others if you have any info or thoughts.

Thanks,
Dave
 

Bondo

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Re: 4.3 LX engine clunking

Ayuh,..........

I'd think a Compression,+ Leak down test would probably lead you somewhere in the diagnosis...........
 

egldvrbags

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Re: 4.3 LX engine clunking

Ayuh,..........

I'd think a Compression,+ Leak down test would probably lead you somewhere in the diagnosis...........

Agreed!

Is it possible w/ the boat inclined for several days water could get into the cylinders? Assuming no obvious problems like head gasket, cracked block, etc.


Dave
 

egldvrbags

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Re: 4.3 LX engine clunking

Update:

Took the boat to a reputable boat mechanic. He did a compression test where cylinders 1-5 were in the 175-180 range and # 6 was 150. He thinks a bearing or rod is the issue in #6. (4.3LX)

No signs of water in the cylinder.

He gave me 3 estimates:

1. Install long block $2572 + $600 labor
2. Install short block $1590 + $850 labor
3. Rebuild engine including new rings, gaskets, seals, bearings, oil pump, turn crank, etc. $1700

Any thoughts?

Dave

PS It's in Wisconsin so he is going to winterize it, store it, and work on it over the winter - winterization and storage usually costs me $600 so at least I'll save this.
 

Haut Medoc

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10,645
Re: 4.3 LX engine clunking


Why would you need a complete rebuild, if it is a bad rod?....
You could probably get a crate engine for cheaper than what they are charging.....
I don't know what storage costs so I can't comment on the last part...;)
 

thrasher

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May 23, 2007
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Re: 4.3 LX engine clunking

Those prices look very competitive, you could look at fixing the bad rod (assuming the crank bearing is not damaged) but the engine swap is easier for the mechanic.. With prices like that I wished I lived up your way! My local dealer quoted me $4000 for a long block (4.3L V6 mercruiser) and $1500 to change out the engines!! I did it myself for $600..
If you decide to go for the new engine, he has given you a very good price, but you might want to check his reputation to be sure he is trustworthy..

Gary
 

egldvrbags

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Re: 4.3 LX engine clunking

Why would you need a complete rebuild, if it is a bad rod?...​


If one rod/bearing is bad, seems to me others might not be far behind. It's a 1995 model, so why not rebuild it if it's already torn apart? Or, should I take the "if it ain't broke, don't fix it" route??​
 

Haut Medoc

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Re: 4.3 LX engine clunking


Dunno, you will find out with some diagnostic tests & teardown......;)
What if it is just a slightly bent push rod or something simple?......
I'm just sayin' don't throw the baby out with the bath water....
It would depend on how many hours are on the engine....
If ya have the bux, throw a new longblock in......
I'm just the type of person who would need to know if I could isolate the problem & fix it.....;):)
 

egldvrbags

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Re: 4.3 LX engine clunking

Ah, I understand your post now. The mechanic, who is very reputable in our area, gave the quote based on a complete rebuild. If it's something simple once it's opened up, then he'll only fix what's needed.

My thoughts were, let him open it up, see what's needed. If it ends up being a complete rebuild, then perhaps go the long block route as the boat itself is in great shape - just doesn't work w/o a motor :(

Thoughts??
 

Bondo

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Re: 4.3 LX engine clunking

If it ends up being a complete rebuild, then perhaps go the long block route as the boat itself is in great shape

Ayuh,........

That sounds like a solid Plan................
 

DayCruiser

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Sep 24, 2004
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Re: 4.3 LX engine clunking

I would go with the complete rebuild. 1700 is a lot better than 3100$ You might get the new long block and it be a lemon. This considering the age of the boat too. Make sure either way that it will be ready by spring
 

egldvrbags

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Messages
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Re: 4.3 LX engine clunking

Thanks all. Since we really only have about 2.5 months of good boating in WI, I just don't want to be stuck next summer w/o a boat.
 
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