Yanmar 4BY2-180 Idle Adjustment

[JVSequoia]

I have a 2011 Yanmar 4BY2-180 Diesel engine (1680 hrs) that is idling at 750 RPM's and seems to run a bit rough. When I raise the RPM's to 800 with the throttle the engine smooths out very nicely. I understand that the idle can be adjusted at the throttle body. Does anyone have any experience with making this adjustment? And where is the throttle body located (do I need to remove the engine covers?). Thanks,

 

[venajeff]

750 rpm sounds like a good idle speed. I would suggest looking into the fuel system. Start by replacing all of the fuel filters. While doing that inspect all of the fuel lines for any leaks and make sure all the hose clamps are tight on all the fittings, all the way back to the fuel tank. If that doesn't fix it you could try running some injector cleaner through. After that you may want to have a mechanic take a look at it. It could be a problem that is first showing up at low rpm but may become a bigger issue later. Better to solve it while the boat is at the dock.

 

[irwinengineering]

You can adjust the idle speed using the Yanmar display.

 

[irwinengineering]

Went to the boat this morning to grab the Yanmar display manual, see pertinent page below. You may need a PIN to get to the configuration menu, I think the default is 3124.

On our 2011 R-27 with 4BY2-180, I found that 780rpm idle avoided the rattle of the oven rack that occurred at 750rpm.

fair seas,
Brendan

 

[venajeff]

If you are having similar vibrations problems and a small change in you idle fixes it then disregard my earlier comments. I was under the impression that the engine had begun running rough. Brendan's fix seams like a very easy solution.

 

[William Sanborn]

I idle same engine at 850 in neutral, of just into gear, very smooth and just enough power to move the boat, forward and reverse.

 

[irwinengineering]

Follow up to my previous post: I had set my idle to 780 rpm to avoid an annoying rattle in the oven. Recently did a Lubri-Moly Diesel Purge and have now turned the idle back down to 750 as it now runs quite a bit smoother. Motor has ~1300 hrs, guess the injectors needed a little TLC. I set up a small purge tank and ran on 50/50 Diesel Purge and diesel fuel for about half an hour, am impressed with the results.