Tom, lots of good suggestions so far. I have one other. When was the last 
time your heat exchanger tubes were rodded out? If you are unfamiliar with 
this, these are the tubes you see inside when the cap is removed. There should 
be a cap on at least 1 end to access the raw water side of the exchanger. If 
even some are plugged it will cause overheating. I had about 40% of mine 
plugged coming back from Port Townsend. It was an 85* day and no wind (of 
coarse) could only motor at 1400 or the alarm would go off. I cleaned mine 
using diluted miuratic acid to soften the build up. Then i rinsed it good, 
followed bu cleaning the tube with some twisted safety wire in my drill. And a 
final wash with the miuratic acid, and another good rinse. 
    Doug MountjoysvPegasusLF38 just west of Ballard, WA.    




------ Original message------From: Tom Buscaglia via CnC-List Date: Sun, May 
29, 2016 09:04To: cnc-list@cnc-list.com;Cc: Tom Buscaglia;Subject:Stus-List 
Overheating YANMAR
We are on our first extended cruise of the year for a clubevent in Olympia WA 
and are hiving a problem with overheating with our3HM35 Yanmar.  Here's the 
deal...

We usually run as about 26-2800 RPM.  Depending on the condition ofthe bottom 
and the prop, that gives us between 6.5-7.3 KTS.  We havehad some intermittent 
issues with overheating, but it was usually mepushing too hard in heavy seas or 
running above the usual RPMrange.  Backing off always relieved the problem.  
And we haveno gauge, so this is all based on the alarm which may or may not 
beaccurate.

As we were heading out this time the Admiral was at the helm and I wasbelow 
messing with something and the alarm went off as we were running atabout 2200 
RPM.  We were able to run at under 2000, but above thatthe alarm sounded and we 
had to back down. We continued on at 4.5KTS.

I checked the strainer and through hull.  All good there. Water seems to be 
exiting the exhaust as usual. I am planning on a haulout and bottom job next 
month, and did not have a diver clean the bottomand prop (should have done that 
for sure).  My assumption was thatthe barnacles on the prop and dirty bottom, 
along with the 15-20 KT headwind were taxing the engine and causing the 
overheating.  But the"experts" in my club feel otherwise.

I tried to get at the gooseneck to see if that might be theproblem.  I was able 
to get the water hose off and poke around inthere with a wire, but decided that 
pulling the exhaust hose was notsomething to try 30 miles from home as if I 
screwed it up and damages theexhaust hose I could be stuck here for  a while.  

I have heard all of the problem YANMAR's have with exhaust back up and 
amwondering if that may actually be the problem.   I have asked tohave it 
checked every tine I get the engine serviced, but there's notelling what that 
entailed or even if it was done....so, when she goesinto the yard for the pain 
job I think replacing the gooseneck with thestainless aftermarket one may be in 
order. 

Here are my questions:

1.      Can the dirty bottomand barnacle encrusted prop- result in an 
overheating problem?

2.      Would a carboned upgooseneck cause a problem like the one I am 
experiencing?

3.      Where can I get oneof those nifty aftermarket stainless goosenecks?

Any additional suggestions are welcome and appreciated!

thx

Tom B
.¤º°`°º¤,¸¸,¤º°`°º¤¤º°`°º¤,¸¸,¤º°`°º¤.
Tom & Lynn Buscaglia
SV Alera
C&C 37+/40
Vashon Island WA
(206) 463-9200
www.sv-alera.com




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