Mercruiser 5.7 reliability question

[Mamier]

Ok, I've posted here before about the purchase of my 1985 Formula with a 260hp engine. Only 270 hours. Its running perfect. But here is my question for you experts. I use to be an outboard man...and very use to the OB running around 3500rpm. Now I look at the rpm on this V8 running 3k-4k rpm and think of my Tahoe (same block) doing the same. Man, I can't see the Tahoe lasting long doing that RPM. Kind of frightens me. Are these Mercruiser's built to take this? Thanks everyone for your thoughts.

 

[Laddies]

Re: Mercruiser 5.7 reliability question

A marine engine will live longer at 4400 than one thats loaded at 3000 it cools better and runs free, a overload engine does not cool properly and is prone to preignition that will cause premature damage to it--Bob

 

[Mamier]

Re: Mercruiser 5.7 reliability question

Thanks Bob! Makes sense. I've read that running this engine is most efficient at 3800rpm. - Evan

 

[Buttanic]

Re: Mercruiser 5.7 reliability question

Your Tahoe is misleading you. It is geared for fuel economey and emission reduction. The lower the rpm the less fuel it burns and emits less harmful emissions. That same engine in a large commercial truck or RV would be geared much lower for pulling heavy loads and would run 3500 to 4000 at 70 mph not 2100 like your Tahoe.

 

[Mamier]

Re: Mercruiser 5.7 reliability question

Thanks Buttanic. I rented a Ryder truck once and remember it working quite hard at 70. Just hope my Mercruiser lasts as long... - Evan

 

[Haut Medoc]

Re: Mercruiser 5.7 reliability question

A 350 SBC is a very good engine. Do you spend most of your time in the Lake Washington or the Sound?............J

 

[Mamier]

Re: Mercruiser 5.7 reliability question

Morning Kopec....100% on Lake WA. Whats the SBC stand for? - Evan

 

[AaronG]

Re: Mercruiser 5.7 reliability question

small block chevy

 

[Haut Medoc]

Re: Mercruiser 5.7 reliability question

Crappy morning is more like it! I don't see any boating happening today

 

[Mamier]

Re: Mercruiser 5.7 reliability question

Kopec. Yea. I agree! <br /><br />Thanks AaronG. I should had figured that one out! Too early here I guess. So i take it that these SBC (if taken care of) will last awhile. Thanks everyone

 

[Mahoney]

Re: Mercruiser 5.7 reliability question

Salmon season opens July 1 on the Sound!

 

[crazy charlie]

Re: Mercruiser 5.7 reliability question

That a great motor!!! I have had a few.It will last a long time and parts and repairs are relatively easy to do and even easier to get a mechanic to do.No one is afraid to work on these.The keys to helping it last long are to make sure it is propped correctly and a fresh water flush after each use.Charlie

 

[Mamier]

Re: Mercruiser 5.7 reliability question

Thanks crazy charlie..its used 100% in fresh water. Has 271 hours on it and starts each and every time with one crank!

 

[Mamier]

Re: Mercruiser 5.7 reliability question

Thanks crazy charlie..its used 100% in fresh water. Has 271 hours on it and starts each and every time with one crank!

 

[Haut Medoc]

Re: Mercruiser 5.7 reliability question

Dungeness crab-July 1! I WILL BE THERE! Mamier, if you moor in Lake Washington, you get a free flush every time you come back in the locks!..J

 

[crazy charlie]

Re: Mercruiser 5.7 reliability question

Sounds like a 260 mercr to me!!! Thats hard to believe low hours.Good luck with it.Charlie

 

[Mamier]

Re: Mercruiser 5.7 reliability question

Thanks Charlie. Yea, I got it from a little ole man in MO. 1985 and 271 hours. Boat needed some elbow grease...but the engine starts right up every time.