Adjusting 2qm15 idle speed

[Derrick Serrer]

Hello everyone,
I recently installed a new to me 2qm15 in my sailboat. I bought the engine used and have no history of it but decided to take a chance. I have installed all new fuel system including a Racor 2 micron filter and new exhaust system including a new mixing elbow. I changed all zincs, fluids, filters etc. All new control cables as well. The engine is plumbed for raw water.
The engine will start and run well at 1100 rpm however it will not idle lower then that. If I try to bring the rpm down the engine slows until it stops rather quickly as though it is not getting any fuel and shakes in the process. When running at 1100 rpm the exhaust is clear and has plenty of water being discharged. I have adjusted the engine stop cable thinking that it might be set wrong but even if it is backed off completely the engine will not run below 1100 rpm. My question is how do I adjust the idle speed on the 2qm15? I have searched the manual but can not seem to locate any instructions to do this.
Thank you

[GordMay]

Are you fairly certain that your Tachometer is reasonably accurate?
Yanmar Tachometers often read about 100 RPM too high, especially near maximum RPM.
The Idle speed for a 2GH series should be somewhere between about 750 to 875 RPM.

[Derrick Serrer]

Hi Gord,
Thanks for the reply. I have no way of determining if the tachometer is accurate but compared to a previous diesel I had, and the sound of other boats in the marina, it does sound fast.
My big concern is that I will damage the transmission when shifting in and out of gear with the engine running at 1100 (1000 if it is out of whack like you say). If that is not a concern then I will simply run it the way it is however it will mean a lot of use of the shifter to keep my speed down when in confined spaces etc.

[Derrick Serrer]

Just thought I would post an answer to my own question in case someone else ever encounters this. It seems that by adjusting the injection limitor in a counter clockwise direction I was able to bring down the RPM. I eventually turned it almost 3/4's of a complete turn. The engine is now idling at approximately 850. If I also factor in the tach possible reading 100 rpm too high then it is at 750 rpm. The sound of the engine is a lot better and it does not vibrate as much now.
Thanks

[Therapy]

Thanks for that bit of knowledge.

Many people do not post the final solution and folks like me don't learn as much.