Yanmar 2QM20 Idle RPM's - SailNet Community
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post #1 of 3 Old 09-12-2013 Thread Starter
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Yanmar 2QM20 Idle RPM's

Hello. I am searching for the proper Idle speed for my '78 2qm20. I have looked in my manuals and can find nothing on Idle rpm or WOT RPM. It seems to run smooth at 850 rpm although it is set at about 550rpm and I have pushed up to 2900 rpm (in neutral). It has about 3000 hours. Also what would be a good cruising RPM? It is a Fisher 25 Motorsailer. Long keel, 10,000 lbs.The prop is a Campbell Sailor 16x11. Any info would be appreciated. Thank you.
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post #2 of 3 Old 09-12-2013
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Re: Yanmar 2QM20 Idle RPM's

The continuous rating of the 2QM20 is 3400RPM and the maximum rating is 3600RPM.

Idle RPM of 800 to 900 RPM is good (you can adjust it to any comfortable value and if it runs smooth at 850 that's where I would put it).

I recommend cruising at 60 to 70 per cent of the continuous rating for efficiency. That's 2040 to 2380 RPM.

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post #3 of 3 Old 09-13-2013 Thread Starter
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Re: Yanmar 2QM20 Idle RPM's

Thank you for your reply.
I think you might be referring to the 2GM20.
After reading and searching many posts I saw where a few people suggested to contact Yanmar Support. Who would of thunk!
The Tech was excellent and even contacted Japan to find the idle speed.
So here goes:
Idling speed ; min. speed at no load; is 600 +-50 rpm
Continuous under load:2600
Max under load for no more than an hour: 2800
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