Engine dies at low idle

[DLORENZ]

Just bought 1990 34 and love it.  When docking and time comes to stop forward motion, with engine in reverse I give it a quick burst  and then throttle back to idle.  this is when engine just dies. It will start right up again. A :xny thoughts. Is idle set too low? Are injectors dirty? What????  Duane in San Diego

[Ken Juul]

Yes it could be all the things you mentioned.  It could also be a miss adjusted throttle cable.  If I pull my throttle all the way back the engines idles at about 700.  It is shaking and banging at that point.  I've found that it runs much smoother if I use 1000 as the idle point.  It has become second nature now, usually get it pretty close by feel and sound, use the tach to fine tune the setting.  At 1000 it slides easily in and out of gear, unless I need a burst of power to overcome wind from the wrong direction, I usually don't need to touch the throttle during docking.

Welcome to the board!  All questions are welcome, but there is a ton of material all ready written.  Use the search function at the top of the page for suggestions on how to clean your injectors/fuel system.

Here is the link to the Knowledge Base.   http://www.c34.org/tech-notes-index/technotes-excel.xls
Many folks have it saved on their favorite page for easy access.  It is a great index of tech notes, projects and discussion from the board.

Please consider joining either the Catalina 34 International Assoc or the Catalina Fleet in San Diego or both.  Information can be found on the home page, www.c34.org   

[Mike and Joanne Stimmler]

My boat does the same thing and when I purchased it, the surveyor indicated that it was a governor problem. I have just lived with it after researching governor repair or replacement.

[Craig Illman]

I do the same as Ken, and try and leave it at 1000 RPM. I attribute it to my high output alternator or slightly over-pitched prop. Obviously, the governer should accomodate the extra load. I live with it.

Craig

[Ron Hill]

Dl & Mike : Don't worry about the governor, it's mainly there so you can't get a high speed over rev.!!

There have been numerous articles about how diesels don't like to be in a low idle. It carbons up the cylinders/injectors and any extra load like a high output alternator or shifting into gear puts a real strain on the engine.  I have mine idling at 1100+ rpm.
It's easy to adjust the idle speed by extending the idle screw.  What I did was to put a small chair tip on the end of that screw - which does the same.  Be sure NOT to fool around with the hi speed screw.   

[Stu Jackson]

Welcome, DLorenz.  Hope you update your profile to post your boat info as noted in the Who Are You thread.

Another resource is the explanation of the C34 website Technical information:  http://c34.org/bbs/index.php?topic=2629.0

There's also a complete set of manuals at www.C34.org for your review.  They could contain the details of the idle screw mechanism.

[Bob K]

I raised my idle to 900 a few months ago to prevent this same type stallng, and to decrease vibration associated with the rough low speed idle, but I was concerned about the extra wear on the transmission when shifting at the  higher idle speed.  I could not find anything in the engine manual regarding recommended or maximum speed when shifting.  I'm glad to hear others have also increased their idle speed - I suppose if it was bad for the transmission, somebody here would know.  By the way, my stalling problem was not the primary reason for making the adjustment  - it only did it occasionally.  I replaced my motor mounts to K75s last winter, and soon found when quickly throttling back it would initiate a very strong vibration - to the pont where I was afraid something would break.  I never had this with the original mounts.  Anyway,the throttle increase cured that issue completely.  Other than that initial quirk, the K75s are superior by far at all engine speeds compared to the OEM mounts. 

[Ron Hill]

Bob : If you are not "chopping" the throttle, but bringing it back firmly - not to sure what the vibration is all about. 
As far as shifting, just make sure that you do reduce the throttle to under 1300RPM and shift smartly making sure the shifter is at it's stop.  I never shift from FWD to REVERSE (or vica versa) without stopping in neutral for a few seconds. 
In 20 seasons (250hrs/yr) - that's alot of shifting!!   

[Bob K]

That is comforting to hear, Ron, thanks!

[DLORENZ]

Thanks to all who had input. I adjusted my throttle stop  to 850 RPM and problem is solved.