[torchlake99]

Found this string I started when we first bought the boat and discovered I did not let all know what was going on and how it ended.    The tach was accurate, so marina suggested we re-pitched the props over winter.  No difference in rpm when I took it out in spring.   Brought out the cummins mechanic and found out someone adjusted the throttle back to hit 2750 at WOT.  With the commons mechanic we adjusted the throttle body connector (believe that is what he called it) on each motor.  We were in the marine at idle, took off the throttle covers at the helm, he was sitting by engines and I was on the helm.  Had me take one engine at a time (after warm up) to wot then I adjusted with a screw driver the stops on the throttle until we were at 3150.  He then adjusted the stop on the throttle body so that when we were at 3150 the spring had a little tension on it .  

That was it.  If I had checked this adjustment before re-pitching props it would have saved me cash and time.   Just wanted to pass this one in case someone else comes into the same situation.  I was not happy with the marina that after checking the tach and they said to re-pitch the props.  This 35 Open was new to me and the first real cruiser I have ever owned.  Big step up from what I had before.  Looking back this should have been checked before going forward with props.  I did order a manual for the cummins engines after this all went on and under the problem solving for low rpm it did say to check this early on in the cascade of possible solutions.  My guess is the previous owner set them back for some reason.  Bottom line order the manual from Cummins and read it.  Great source of information, with I had one before spending the money on altering the props (twice because  we had to re-pitch them back to factory) .  Enjoying the boat and looking forward to a great boating season.  
Kent

[ReelMagic]

We all live and learn. Glad to see you solved your problem and that you re-pitched the props back to factory spec. It was the right, although somewhat expensive, way to go...... Have learned somethings on my 6CTA Cummins the same way, live and learn.....

[trit21]

IF you are adjusting the no load RPM (no load speed as seen on the Cummins data sheets) then you are still mis-adjusted. Spec for CPL 2208 (not sure if that is what you have) should be 

High Idle Speed Range Min    3300
High Idle Speed Range Max   3400

So you should be between those 2 numbers. I have enclosed the data sheet, High Idle can be seen near the top. 

[torchlake99]

Hi Tom

Thanks for the heads up and information.  Will have to check the CPL number when I next get to the boat.  Really like the engines and hope to get a long life out of them.

Cheers 

Kent

[jmk]

Tom is 100% correct, but have we verified that you have 370 not 330? Read us your data plate numbers. I still recommend you use a phototach for something this important. $50 online. After verifying your high idle you still need to check WOT under load. I doubt you will regret pitching down in the end, unless it turns out you need to go further down.


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[torchlake99]

Hello

We have the 370hp for sure.  From a Cummins bill it reads...   B5.9-M3 (370)   CPL220800   
Re-pitched the 3 blade props to factory and last year, will keep as spares.    Put on the below props last year.
Acme cnc machined props 24x28x4 blade nibral
the 4 blade props turn 3050 with a full load.  Handle beautiful around the marina and I gained 2 mph in our normal cruise speed, 2500 rpm's which gives about 28 mph or close to 25 kph

I will look into the rpm situation again this spring.  

Thanks
Kent