MerCruiser instructions for the 20 hour break in period

[jezzb]

As I have just rebuilt my Merc 7.4MPI, I have asked and received the following information from Mercruiser, which I thought of sharing with you. I hope you will find it useful.

Best Regards: Jezz

The following are the MerCruiser instructions for the 20 hour
break in period.  Thank you MerCruiser Consumer Service.


* Do not operate below 1500 RPM for extended periods of time for the first
10 hours. Shift into gear as soon as possible after starting and advance
throttle above 1500 rpm if conditions permit safe operation.

* Do not operate at one speed consistently for extended periods.

* Do not exceed 3/4 throttle during the first 10 hours. During next 10
hours, occasional operation is permissible( 5 minutes at a time maximum)

* Do not operate at full throttle until the engine reaches normal operating
temperature.

* Frequently check engine oil level. Add oil as needed. It is normal for
oil consumption to be high during the break-in period.

[merwin10]

What! So I guess you need to upset your marina by waking them  going 1500 rpm right away! Then you vary the speed every so often between 1500 to 3100 rpm. Stopping ever so often to check the oil! Then start up and give it a hole shot at 1500 rpm or more!

Oh well if that don't get the official's to notice you just run them over!

Mike -  

[nwaring]

That is the steps I went through last year.  If you have a long no-wake zone the 1500rpm thing is hard not to do.  I didn't use any oil.

Niles

[Talon]

I did the same last September and used TONS of oil. They quit using oil around 15 hours or so.

[jezzb]

Do you think that it is a good idea to run the engine when the boat is in the garage? Or it is not so good idea because the engine won't have any load ?

Jezz

[Talon]

Dunno - mine won't fit in the garage

Seriously, I'm not sure if it makes a difference. I'd contact Mercruiser to find out. My guess is that they will say the boat should be under load, or recommend a different break in procedure for no-load situations.

[BigSioux232]

I would think it would need to be under load.  If you break an engine in properly using the instructions, you have to exceed the recommended idle RPM anyway.  

When I bought my previous boat new with a Volvo 5.0Gi, the manual prescribed to stay below 3000 RPM for the first 5 hours varying speed.   Most auto manufacturers have eliminated break in altogether.  Interesting that Merc still prescribes 10 hrs.

[Dave M]

Kind of makes you gun shy of buying a demo boat. You know they didn't go by book, First thing they do is show you how fast it goes.

I tried to follow thier recommendations as close as I could. I had a real hard time starting the boat and shoving it in gear with no warm up. Don't think I made the 20 hour rule before WOT though. Listening to the thru hull takes about 20 years and a few I.Q. points off ya(maybe just me) .

[Talon]

lol   8)

[merwin10]

Why would you need to break in a Rinker boat engine! Thought that all the boats spend a couple of days in a tank being checked out. Seems like the engine might already be broke in by the time you get it!!! Agh!!! I know that several of the members have shown pictures of the boats in the tanks being tested ao they must have some hours on the meter. This is one of the Quality checks that has helped Rinker do well on the JD Powers poll. The little things that can go wrong are weeded out in the factory. So I wonder how much good staying with the recommended break in is going to be! I know one of the checks must be to see if the engine develops full rpm, that alone breaks the 20 hour breakin rules.

Just some food for thought!

Mike -  

[jezzb]

I cantacted Mercruiser and asked them if they had a procedure for an Engine Break in on lland and this was their reply:
"Good Morning. We regretfully do not have a procedure for breaking the
engine in on the garden hose or on land. Have a great season. MerCruiser
Consumer Service.
"

Most new cars do not need the break in. I was told that the break in is done on the bench at the factory. I suppose that it was done without load. Or do they  connect something to the drive shafts?

Kind regards
Jesmond

[4LakeBums]

They do quality control checks at the factory.  When I looked at my new boat last week the hour meter read four tenths of an hour.

[Ronnie]

I took mine easy the first 5 hrs Then I drove it like I was going to drive it the rest of it's life...or at least as long as I'm going to own it. but did the 20  hrs service like clockwork.