4.3 Mercruiser blow up easy?

[Gromulin]

I've been following CL for about 3 months now. I keep noticing something: whenever I see a boat that advertises "new motor, only 10 hours!" it always seems to be a Merc 4.3 that had been replaced. Almost all the boats are between 2000 and 2005. Have not seen any 5.0 or 5.7 with similar stories..at least not advertised. They all seem to be cosmetically well kept, look like new and otherwise in good shape.

So I guess my choices for speculating are:

1- The ones I've seen are usually 18-19 footers, typical first-boat. No upkeep by rookie boaters? 25 year olds with HELOCS..rode hard, put up wet, blowed up early? Dude...check out this gauge...it's TOTALLY redlined, dude! Awesome!

2- Something makes the 4.3 more prone to gettin blowed up than the 5.0 or 5.7. Bad cooling system? More prone to overheating? (I'm also guessing that overheating is the most likely to cause a low hour motor to need a total replacement)

3- My completely unscientific and subjective survey is just that...BS..(hey, it worked for the Global Warming guys!) I just happened to only notice blowed up 4.3's in my price range (under 16K, 2000 or newer). If I was searching in a higher price range, I might see more 5.0 / 5.7 with similar stories.

Thoughts? Opinions? Wild *** guesses?

 

[John_S]

Re: 4.3 Mercruiser blow up easy?

The 4.3Ls have been around a long time. I'd bet most didn't blow up or wear out. Freeze or water damage would be my guess. Allot more entry boats with 4.3's because V8's price point usually kills those great package prices.

 

[Gromulin]

Re: 4.3 Mercruiser blow up easy?

I'm in the Sacramento area..trust me...no frozen blocks around here

 

[John_S]

Re: 4.3 Mercruiser blow up easy?

I'm in the Sacramento area..trust me...no frozen blocks around here

Which leads to over confidence and newbies not winterizing.

http://en.wikipedia.org/wiki/Sacramento,_California#Climate

On average, the daily minimum temperature drops below 32 ?F (0 ?C) on 18 days each year

 

[Gromulin]

Re: 4.3 Mercruiser blow up easy?

I'm quite aware of the climate here. Thanks, tho.

 

[KJSmitty]

Re: 4.3 Mercruiser blow up easy?

Which leads to over confidence and newbies not winterizing.

http://en.wikipedia.org/wiki/Sacramento,_California#Climate

On average, the daily minimum temperature drops below 32 ?F (0 ?C) on 18 days each year

Lived in Sac for numerous years. We nor anyone I knew with a boat ever winterized like one may elsewhere. Had nothing to do with being a noob or overconfident. Crap, we would use the boat 9-10 months out of the year! Never once do I remember it freezing. And as even your "data" states: the temp may dip blow 32 degrees yet always gets above freezing during the day. You would never even see a puddle freeze let alone an engine there,,, "typically."

I'm with the op and agree it's seems like the V6's are prone to issues - but I also agree with you that due to their numbers/price we would obviously hear about more, than others etc..

I miss the Sacramento weather. Texas isn't bad yet it's way more humid!


Cheers

 

[achris]

Re: 4.3 Mercruiser blow up easy?

.... A lot more entry boats with 4.3's because V8's price point usually kills those great package prices.

...The ones I've seen are usually 18-19 footers, typical first-boat. No upkeep by rookie boaters? 25 year olds with HELOCS..rode hard, put up wet, blowed up early? Dude...check out this gauge...it's TOTALLY redlined, dude! Awesome!...

That sort of sums it up....

I'm on my second 4.3. The first is 16 years old and still going strong in a friends boat with over 1300 hours on it. The current one is 4 years old and I hate Merc for it... (see THIS thread) but it has almost 300 hours and is running well (apart from the little oil leak problem ). Took it out last weekend and ran 25 minutes from the marina to my fishing spot at WOT . Not a lot of hull in the water for most of the trip....

Chris.....

 

[Gromulin]

Re: 4.3 Mercruiser blow up easy?

Crap, we would use the boat 9-10 months out of the year! Never once do I remember it freezing....
I miss the Sacramento weather. Texas isn't bad yet it's way more humid!
Cheers

Yep, we get a "hard" freeze for about two nights every three years. Might have a puddle to crack under your feet in the morning. Had to put duct tape over an exposed sprinkler pipe one year when it got really bad.

I sure like the way Texas sounds...but that humidity would kill me. At least in Sacto it's a *dry* heat, makes you really appreciate those delta breezes at night!

 

[180shabah]

Re: 4.3 Mercruiser blow up easy?

That is the one piece manifold era - they could not be taken apart and inspected for deterioration. Of course a lot of two piece manifolds never get inspected either, but the result is the same.

If the exhaust perforates and is not replaced ASAP the engine is toast. Either slow rust build up from the moisture, or a hydrolock and you need a new engine instantly.

There is no real reason to shy away from a 4.3

 

[rodbolt]

Re: 4.3 Mercruiser blow up easy?

done 3 so far this year,the forth is on the rack waiting for the insurance adjuster.
first the had the same story, they moved here in the spring of 09,were told by some locals,they moved here in the winter of 09, that it doesnt get cold enough on the outerbanks to warrent winterizeing.
lost 2 5.7s and a 4.3.
the one on the rack is twin 5.7 raw water cooled.
his neighbor said a light bulb in the engine box was sufficient.
BOTH outbaord manifolds are cracked and water is getting in the engine and thats where I stopped.
guy brought it in for a tune up cause it wont run over 3000 RPM this spring.

you can roll the dice,only takes snake eyes once.
sometimes,especially on trailer boats a few hours at 28 degrees is all she wrote.

 

[Gromulin]

Re: 4.3 Mercruiser blow up easy?

you can roll the dice,only takes snake eyes once.
sometimes,especially on trailer boats a few hours at 28 degrees is all she wrote.

I hear ya, not saying it's not possible, and I NEVER argue with someone that works in a business I call a hobby...but I've not heard of any around here.

It just seems more likely, in my mind, that overheating, due to bad upkeep and abuse - not changing the impeller, flushing, sucking up sand, etc, and new boaters not realizing that if the temp gets above boiling, it turns to steam PDQ, and can cook a whole motor SO much faster than a car.

It's so counterintuitive to people...how can I be overheating??? I'm on a Lake!!! And they keep trying to make it back instead of stopping and calling for a tow... These stories I HAVE heard around here, is all I'm saying. And I, admittedly, don't know jack...just speculating, thats all.

 

[rodbolt]

Re: 4.3 Mercruiser blow up easy?

hear that tale a bunch.
most failures are from lack of maint.
10 year old saltwater cooled maifolds and risers,5 year old bellows,5 year old seawater pumps.
first thing I ask is when were these maint items done last.
standard reply is it never needed it.
some years back I rebuilt a crossflow 140 for a customer.
his boat had ben in for maint about 2 months earlier.
I asked about doing Tstat and water pump service.
he told me it was all working good.
until the impeller failed and smoked a piston.
then he said it only overheated once.
when I did the bill I seperated the labor to remove,reinstall the gear case and the pump assy.
then I showed him the labor and parts bill to correct the damage the pump did.
even this guy noted the price of the pump job remained the same.
only change were the extra parts and labor.
I check my shirt occasionally and nope I am not the Maytag man.
\

 

[TilliamWe]

Re: 4.3 Mercruiser blow up easy?

Grom, I asked the same question about 3.0s a few years ago. LOTS of posts about trouble with them. As i was told then, and I am telling you now, since there are more 3.0s and 4.3s sold than there are 5.7s, it makes sense that you're going to hear about problems with them. Couple that to the fact they are usually in entry-level boats, that have entry-level owners (who perform entry level maintenance), they get abused and broken.

 

[John_S]

Re: 4.3 Mercruiser blow up easy?

It just seems more likely, in my mind, that overheating, due to bad upkeep and abuse - not changing the impeller, flushing, sucking up sand, etc, and new boaters not realizing that if the temp gets above boiling, it turns to steam PDQ, and can cook a whole motor SO much faster than a car.

Yes, but on the years you are talking about, there is also an audible alarm. It goes off at 200 degrees. It is not easily ignored. Melting exhaust hoses also tend to get peoples attention.

The water leaking in from the exhaust manifolds, especially on non-maintained engines of any type, will quickly waste them.

 

[labrooker]

Re: 4.3 Mercruiser blow up easy?

On the block freezing issue there u say puddles dont freeze. Thats because of the tempeture of the ground it stays warm enough for the puddle not to freeze.(warm below cold above.) but an engine block is surrounded by cast iron that will cool down and allow water inside to freeze much faster than a puddle on the ground. I also have a 4.3 though that has a cracked block. bought it like that and seems to me that most people are just lazy and dont properly winterize em.

 

[paultjohnson]

Re: 4.3 Mercruiser blow up easy?

I run the dog **** out of my 86 Thundercraft w a 4.3. It doesnt leak, always starts, use no oil, and still has great compression. I also maintain it, use good oil,change impellars etc... let it warm up before I hammer down and always monitor my temp and oil pressure gauge. A 4.3 is basically a chevy 350 minus 2 cylinders, A 350 is one of the most bullet proof, long lasting engins ever made- I M H O of course. I believe if you take care of it , it will take care of you.....