[C320-list] Low speed under Load

[JeffWillis111 at aol.com]

Hey Don,
 
You said "serviced prop."   Did they remove your MaxProp?   If so,  when it 
was reinstalled they may not have put all the "gears" back  in the right 
positions,  essentially re-pitching your prop for  you.    Not sure of the 
model/age of your prop, but I had to haul  the boat to remove and re set my 
prop.  No local divers were willin to  attempt in the dark, murky water of SW 
Fla.
 
I have seen youtube videos of divers on the west coast performing this work 
 though....
 
Just a thought....Godd luck
 
Jeff Willis
 
 
In a message dated 7/13/2015 3:26:58 P.M. Eastern Daylight Time,  
Catalina at thehares.com writes:

Well...  

First, to be getting 5kts at 2000 rpm means you're well over  pitched
regardless of which prop you have.  So, you'll be building up  carbon in the
elbow like crazy this way.  Even if it seems ok it  isn't.  So I'm guessing
your exhaust elbow is probably clogged unless  you can rev to 3800 RPM 
easily
in neutral.  Since your diver says your  prop is clean, there are really 
only
a few things I can think of that can  keep you from getting over 2800 rpm
under way.

1:  Over pitched  prop
2:  Clogged elbow
3:  Dirty prop  (ruled this one  out)
4:  Dirty Primary or Secondary fuel filter

I think #1  caused #2.

-Jeff Hare
#809

-----Original  Message-----
From: C320-list  [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Donald  Lawson
Sent: Monday, July 13, 2015 2:33 PM
To:  C320-List at Catalina320.com
Subject: [C320-list] Low speed under  Load

All
I have 2004 320 with a Yanmar 3YM30 fitted with a 15x9  MaxProp by PO.
Everything has worked well for 3 years. At last spring  haulout I had the
prop serviced and bottom painted. Boat worked great.  Recently I get 5 knots
at 2000 rpm, which is normal.  However there is  no increase in boat speed
past 5 knots up to 2800rpm.  Cant' get above  2800 rpm. Rpm to 3000+ easily
in neutral.  No visible exhaust  at  2000rpm. 
Skipper says some minor black smoke at 2800 rpm. Seemed like a  mist to me.
Recently serviced.  Got fuel and air OK. Had diver check  MaxProp.  Seems 
OK.
Diver cleans bottom and prop once a  month.
Anyone had a transmission trouble with a Yanmar? Starting to grasp  at
straws.

Don Lawson
"Mandolin Wind"  
Ventura,  CA