[C320-list] exhaust blockage

[Jeff Hare]

Something else you could check is the governor.  This is the assembly just below the front end of the heat exchanger where the throttle cable connects to the engine.

You might take the cable off this arm and make sure that the arm actually moves through the whole range.  We had a small seawater leak in the heat exchanger just above it which dripped and ran down over the place where this arm enters the engine.  The arm got difficult to move and by removing the cable and spraying a little penetrating oil in there we were able to free it up so that it again moved smoothly across the whole range.

As I point out from time to time, the engine throttle lever really controls a speed governor.  When you set the lever for 1500 RPM, the governor keeps the engine running at a constant 1500 RPM by automatically varying the fuel delivery as the load on the engine increases and decreases.  So, if the exhaust elbow or other exhaust obstruction isn’t the problem and the Air intake isn't somehow blocked up, the fuel system is next.  

Chris is right that there were some cold start(?) problems related to the routing of the fuel return line, but I would be surprised if those problems weren't totally resolved in all affected hulls by now.

BTW, what kind of propeller do you have and do you know what pitch?

-Jeff Hare

-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Chris Burti
Sent: Friday, November 20, 2015 4:26 PM
To: 320 <C320-List at catalina320.com>
Subject: Re: [C320-list] exhaust blockage

The replies of the others who have posted about the elbow are most likely correct, but before you blow a gasket in your wallet, try using the pump on the Racor fuel filter and stroking it about 10 times. On the series around our era, there is reportedly a check valve in the fuel return line that lets air back up into the injectors. Then the engine runs fine but not over about 1500 RPM. There is a re-plumbing kit available from Yanmar that is a bit pricey and I've never bothered to fix ours because the re-plumbing is a bit of a pain and pumping isn't.

Can't hurt to try first.

Chris Burti
Commitment, #867

On Fri, Nov 20, 2015 at 1:30 PM, Steve Turbis <sturbis at gmail.com> wrote:

> Has anyone had this problem. I can't get my Yanmar diesel over 1700 
> RPMs and my mechanic says I have to replace the elbow and manifold 
> because typically this engine builds up soot in this area and the 
> motor can't function properly because exhaust keeps backing into the 
> motor. Any ideas if this is true? He wants to charge about $1000 to repair it.
>
> Steve
> "AT LAST"
> Dana Point Ca
>



--
Chris Burti
Farmville, NC