[C320-list] Diesel vibration, 1999 Yanmar Check both idle RPM and throttle end gap

[Robert Sloat]

I had a similar problem with my 3GM30F a few years ago.  The idle spec is 850+/-25 RPM and mine was OK, but per the Yanmar factory service manual there also has to be a gap of  0.4 to 0.11 inches on the end of the throttle cable where it connects to the link that sets the idle.  My idle speed was OK, but the gap was too small so the engine shuttered when quickly reducing engine RPM.  It finally settled in at the correct idle RPM.  The at rest idle can be adjusted using the screw that contacts the link that connects to the regulator cable going to your helm throttle.The screw rests against the link and is locked in place with a small nut.  This is on the front right of the engine.  The gap on the end of the throttle cable where it connects to the link is adjusted with the nut and locking nut at the end of the throttle cable just above the idle adjusting screw at the right front of the engine.  I got the gap to spec and the problem went away.


On Jun 17, 2014, at 7:16 AM, Bill Hutt <bhutt at windstream.net> wrote:

> Group,
> 
> While we're on the subject, when I quickly rev down the engine (as when docking) I get a terrible shudder. If I rev down slowly, no issues.
> When I first got the boat the mechanic said no big deal. Other than that engine seems to run fine.
> Any ideas/ suggestions?
> Thanks,
> Bill Hutt
> Caribbean Soul
> Cleveland, Ohio
> 
> Sent from my iPad

Bob Sloat
Savannah 894 (2002)
Waukegan Harbor, IL