Engine Problem?

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Weasel

Weasel

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May 23, 2004
159
Beneteau 331 Iuka, MS
Checked out my buddys boat this weekend and found a perplexing problem. Engine will only rev to 2900 rpm with transmission engaged. Without transmission engaged the engine will rev to 3600 rpm. Throttle / gearshift lever has same arc of travel. Low time engine, about 200 hours. Yanmar 2 cyl engine. Beneteau 323. Any suggestions? (This model has the throttle / gearshift on a small blister housing located on the pedestal tubing.)
 
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jacrider

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Mar 5, 2012
20
Beneteau First 47.7 Parry Sound, ON
While I am not an expert, but it sounds like the prop isn't matched to the boat. I think your description sounds like too much pitch, and but again, I there are experts who can provide better knowledge.
 
D

DJBrookster

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May 20, 2011
34
Beneteau Clipper 323 St Peter Port
Weasel said:
Checked out my buddys boat this weekend and found a perplexing problem. Engine will only rev to 2900 rpm with transmission engaged. Without transmission engaged the engine will rev to 3600 rpm. Throttle / gearshift lever has same arc of travel. Low time engine, about 200 hours. Yanmar 2 cyl engine. Beneteau 323. Any suggestions? (This model has the throttle / gearshift on a small blister housing located on the pedestal tubing.)
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We have a 323 but a yanmar 3ym20. Not sure why your racing the engine in neutral in the first place. In gear you should only really be running the engine at 85 percent of max revs anyway,
 
Weasel

Weasel

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May 23, 2004
159
Beneteau 331 Iuka, MS
I agree DJ, but the method to my madness was to see if the throttle was binding when it was in the sweatshirt mode. The prop is the Beneteau factory standard. The engine has a do not exceed of 3600 revs, although you should cruise at ~ 85%, but you have the extra capacity if you need it . Thanks for your response!
 
Ron20324

Ron20324

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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
My B323 3YM20 does 3600- usually- in or out of gear. Right now, it has not been hauled since August 2010, and the dirty bottom and prop are holding the in-gear RPM to 3100.I will haul out after Memorial Day, so will see if the cleaning and paint does not restore me to 3600. I cruise at 3000.
 
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A

arf145

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Nov 4, 2010
495
Beneteau 331 Deale, MD
It really doesn't take many barnacles on the prop to slow it down considerably. I'd check the prop for crud.
 
anchorclanker

anchorclanker

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May 27, 2012
1,152
Oday 222 Beaver Lake, Arkansas
DJBrookster said:
Not sure why your racing the engine in neutral in the first place. In gear you should only really be running the engine at 85 percent of max revs anyway,
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Just an FYI, diesels are run up to speed in neutral to adjust the max no load speed. Running them up in neutral to note the max speed on the the tach is how you check max no load speed. Though you only do it long enough to check/adjust, you dont want to leave it there.

If the right propeller is used, the engine should reach that same RPM. 3600 in this instance.

If its not, and it was before, you need to look under the boat. If everything looks good down there, start looking at the engine's mechanical condition and state of tune.
 
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