4JH57 Break In

[SteveInMD]

I'm trying to do right by my new Yanmar 4JH57 and properly break it in. I have read the break in procedure... During the first 10 hours run the engine at 60 - 70% of load most of the time. Do not idle for more than 30 minutes and do not run at wide open throttle for more than one minute at a time.

While reading the manual I notice you can set the LCD to show "ENG Ld" which is engine load percentage.

The problem is, when I try to get to 60 - 70% of load I'm motoring along at around 9 knots and I'm getting near the max rated RPMs. I backed off and did not run that way for more than a minute. 45 - 50% of load still seems fast to me, but more reasonable.

My question is... can I trust the ENG Ld reading on the LCD? Is it accurately showing me engine load and I should run it up to 60 - 70%? If not, how am I supposed to tell what 60 - 70% is?

 

[Davidasailor26]

You say that 70% load was showing near your max rated RPM. Have you actually gone to wide open throttle to see what the tach reads? It is possible that the tach is reading high and making you think you're closer to the redline than you are.

 

[Paul Mermelstein]

The 4JH series usually has a WOT of around 3800 rpm. Is that what you are seeing?

 

[SteveInMD]

The 4JH series usually has a WOT of around 3800 rpm. Is that what you are seeing?

The 4JH57 has a max rated rpm of 3,000 rpm. I think this is lower than other 4JH motors.

Perhaps the engine load % shown on the LCD is not good information to use, and I should just go by rpm. I'm not sure how the computer calculates load %. It's unfortunate that Yanmar put engine load on the break-in procedures if you can't rely on the LCD readout for this.

 

[Paul Mermelstein]

I just looked at the user manual online: http://www.yanmarmarine.eu/theme/yanmarportal/uploadedFiles/Marine/productDownloads/Pleasure - operation manual/4JH-Common Rail/0AJHC-EN0011.pdf)

It says operate at 400 to 500 rpm below max, which is approx. 60%-70% of load. So, I'd go by rpm.

 

[SteveInMD]

In my case 400 - 500 rpm below max does not seem to equal 60 - 70% of load, that's where the confusion is. I'll just go by rpm.

 

[Ron20324]

[QUOTE...My question is... can I trust the ENG Ld reading on the LCD? Is it accurately showing me engine load and I should run it up to 60 - 70%? If not, how am I supposed to tell what 60 - 70% is?[/QUOTE]

I'm not familiar with what your are reading as "engine load" on the LCD. What is that measureing? RsPM, horsepower, or what.

 

[SteveInMD]

You can go into the LCD setup and turn on a number of items not on by default. ENG Ld is supposed to be Engine Load Percentage, but I can't tell you how the computer calculates it. Perhaps someone else can.