7.4 Mercruiser Engine Life Expectancy

msd58 · Oct 30, 2006

I am looking a boat -an express cruiser 28.5' single engine 1998 EFI with 435 hours. If engine was maintained properly what is the life expectancy on that motor?

tommays · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

FWC or RAW water

Tommays

msd58 · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

FWC Bravo III

QC · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

Some limited 7.4 life expectancy info

msd58 · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

I am asking about the engine not the drive

Bondo · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

5000hrs.+ is not unheard of..... 3000hrs. is realistic.......

With Proper Maintenance of course............

QC · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

msd58 said:
I am asking about the engine not the drive

There is some engine life info in there as well . . .

msd58 · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

bond-o said:
5000hrs.+ is not unheard of..... 3000hrs. is realistic.......

With Proper Maintenance of course............

My reason for asking ths question to begin with is I heard that 7.4's get about an average of 700 hours before a rebuild is needed. I respect first, the answers from this forum. This is why asked.

Bondo · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

Are you talking about a Hot-Rod 454,..........
I've seen motors that Need that sort of Service Schedule,......
In Race Boats,+ Poker Runners........

But, in a Cruiser,........See My 1st post.......

xtraham · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

msd58...
eastern shore, or western shore ?

Drowned Rat · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

QC, in the link you provided, someone suggested using synthetic drive oil. Who makes a synthetic drive oil you can put in a merc. L/U? I/O's are new to me, the oil the manual says to use is, of course, merc oil and it's blue, but I have no idea what kind of oil it is even. Is it regular 75W90? Thanks for the help.

msd58 · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

Thank I appreciate your input. Yes its standard mercruiser 7.4 in single engined 28.5" cruiser 10'2 beam

Bondo · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

Drowned said:
QC, in the link you provided, someone suggested using synthetic drive oil. Who makes a synthetic drive oil you can put in a merc. L/U? I/O's are new to me, the oil the manual says to use is, of course, merc oil and it's blue, but I have no idea what kind of oil it is even. Is it regular 75W90? Thanks for the help.

Mine is full of either Mobil 1, or Penzoil, in 75W/90 full Syn. oil..........
Depends on Which 1 is on the shelf.........

Merc also does a full Syn. oil,....... I believe it's Green.......
Mercruiser High Proformance or something like that......

msd,.......
That motor will last Forever,..........
With,....
Proper Maintenance..........

sailsmanship · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

Just my 2 cents.. Have you sea trialed the boat? A 29 foot boat with a 10.2 beam might be a little heavy for a single. I had a 26 footer with a 8.5 beam and my 7.4l with Bravo 2 was just adequate

QC · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

Yeah DR, listen to Bondo. I am still currently suckered into using Merc products. I am very close to jumping off that bandwagon . . .

msd58 · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

sailsmanship said:
Just my 2 cents.. Have you sea trialed the boat? A 29 foot boat with a 10.2 beam might be a little heavy for a single. I had a 26 footer with a 8.5 beam and my 7.4l with Bravo 2 was just adequate

Sea Trial performance: results were 3600 rpm @ 26mph and 4100 rpm at 31 mph. Four people, clean bottom and 40 galllons of fuel. Winds 5-10 light chop

Don S · Oct 30, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

If it is now or ever has been seriously overpropped, deduct 1500 to 2000 hours from that realistic 3000 hours bondo mentioned.

msd58 · Oct 31, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

Don said:
If it is now or ever has been seriously overpropped, deduct 1500 to 2000 hours from that realistic 3000 hours bondo mentioned.

Its has always been the OEM Bravo III props since purchased new.

Bondo · Oct 31, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

If that 4100RPMs is at WOT,.........
You're lugging the motor,......
Ya Gotta get it up to 4400/4600RPMs..........

msd58 · Oct 31, 2006

Re: 7.4 Mercruiser Engine Life Expectancy

bond-o said:
If that 4100RPMs is at WOT,.........
You're lugging the motor,......
Ya Gotta get it up to 4400/4600RPMs..........

It had more to go but that day thats what we did

7.4 Mercruiser Engine Life Expectancy

Petty Officer 1st Class

Admiral

Petty Officer 1st Class

Supreme Mariner

Petty Officer 1st Class

Moderator

Supreme Mariner

Petty Officer 1st Class

Moderator

Lieutenant

Captain

Petty Officer 1st Class

Moderator

Petty Officer 1st Class

Supreme Mariner

Petty Officer 1st Class

Honorary Moderator Emeritus

Petty Officer 1st Class

Moderator

Petty Officer 1st Class