[C320-list] Trouble starting Yanmar 3GM

[Louis Friedman via C320-list]

Hi all,

We have a 1999 320, previous owner had told me that the Yanmar when cold
would not start unless it was primed with the manuel fuel pump. He had
thought there might be a fuel leak. I had our marina check it out(they are
certified for Yanmar engines) - they could not find any leaks and thought
it was fine. If the engine has been run within a day, it's fine. But more
than that and it needs priming to get fuel in the line - any other thoughts
on why this would be. Anyone have a similar issue?

Lou Friedman
s/v Miss Adventure
Hull #623

[r. scott via C320-list]

i had the exact same problem on hull 615. had a very slow leak on line to
fuel pump. one drop a week. racor pump primes very well if fuel pump is
on wrong position on the cam

[Daniel Kolean via C320-list]

I had trouble cold starting too. Hull #498, same Yanmar. What works for me is slowly open the throttle, pull it down, then put it back up to 1/2 to 3/4 throttle, then crank and bring throttle down when it fires.

Dan Kolean
ENRICH #498
Sent from my iPhone

> On Jul 7, 2024, at 1:45 PM, r. scott via C320-list <c320...@lists.catalina320.com> wrote:
>
> i had the exact same problem on hull 615. had a very slow leak on line to

[Jack Brennan via C320-list]

Losing prime on a diesel like that often comes from a pinhole leak. They are maddening to trace.

It follows that if you do have a leak, there is fuel getting out somewhere to allow air into the system. The first step should be to examine the fuel system from the tank to the injectors, looking for signs of diesel.

The fuel line from the tank to the Racor is downhill, so that shouldn't be causing you to lose prime. The Racor and the lift pump should be suspects. As should the fuel lines where the hose clamps bite into them.

Once fuel gets to the engine, the connectors change from clamps to those pressure fittings that are sealed with copper washers. Those are potential problems. You also have a potential leak spot at the bleed screw on the secondary filter, which is also sealed with a copper washer.

I hated the OEM Racor, so I replaced it with a Racor 500 that I bolted into the bulkhead that separates the aft cabin from the port stern locker. It's easily visible just by lifting the lid on the locker. It's installed at the same height as the fitting on the tank where the fuel exits so it doesn't have to run uphill.

Changing filters is easy, unlike the OEM, once you fit yourself into the locker.

I also changed all of the fuel lines and clamps leading up to the engine. I bought some copper washers from the Yanmar dealer and also changed them. Buy a bunch of them. You can't have too many.

A surprise benefit came when my manual lift pump died. With the Racor 500 higher up, the fuel kept flowing even when the pump wasn't working. I couldn't go very fast, but I got into my slip.

Good luck.

Jack Brennan
Sonas, 1998 Catalina 320
Tierra Verde, Fl.



________________________________

[Louis Friedman via C320-list]

Jack,

That may be more than I have time or the ability to do, might have to wait
for fall to have the yard take another look. thanks.
Dan - just to clarify, you open the throttle before you crank the engine?
and crank the engine with the throttle at 3/4 to half open?

--
Louis Friedman, DO, FACP
Woodbridge Medical Associates
www.woodbridgemed.com
732-634-0036

[Jack Brennan via C320-list]

Hi Louis:

Just don't ignore it for too long. Small problems can develop into big ones when you neglect them.

It sounds like you might be new to diesels. Don't get too intimidated about doing your own repairs. Everything I described can be done with a screwdriver and a wrench, with a hand drill for mounting a new Racor filter. The trickiest part is bleeding air from the line, which is not really tricky on a Yanmar.

A good way to prepare yourself is to buy Nigel Calder's book on diesel engines.

Jack Brennan
Sonas, 1998 Catalina 320
Tierra Verde, Fl.
________________________________

From: C320-list <c320-lis...@lists.catalina320.com> on behalf of Louis Friedman via C320-list <c320...@lists.catalina320.com>
Sent: Sunday, July 7, 2024 6:52 PM
To: C320...@catalina320.com <C320...@catalina320.com>
Cc: Louis Friedman <lou...@gmail.com>
Subject: Re: [C320-list] Trouble starting Yanmar 3GM

www.woodbridgemed.com<http://www.woodbridgemed.com>
732-634-0036

[Wandering Star via C320-list]

Louis,
Jack is right. Nigel’s book is the best and my first go-to. I also recommend Clymer’s Guide to your Yanmar model. Super helpful. But more importantly, I started with ZERO knowledge about diesel's and if I can learn how to do all this, through the help of this blog site, so can you!!

Sara
Wandering Star
Seattle
2000/#707

> On Jul 7, 2024, at 4:48 PM, Jack Brennan via C320-list <c320...@lists.catalina320.com> wrote:
>
> Hi Louis:

[Louis Friedman via C320-list]

Thanks all. I've been mostly looking at youtube videos diy stuff. But will
pick up the book!

732-634-0036

[Kim Chapman via C320-list]

Have you tried giving it a bunch of throttle when it's even a bit cold. My
engine is hard to start, without throttle, after a few days. It starts
right up with the extra throttle.

Kim Chapman
C320 #416
Sanity

[ART HARDEN via C320-list]

I had a Yanmar in a Capri 26 and a Catalina 28. In my Capri 26, I found that the electric pump had an extra filter in the pump. With a Rayco filter and the engine filter the electric pump filter becomes number three. This may or may not be a problem since I have a Perkins engine on Tortuga. But it may be something to check out.

Sent from my iPhone
Art Harden
Catalina 320 "Tortuga" E-62
937.885.9380 (o)
937.477.5544 (m)

> On Jul 7, 2024, at 9:30 PM, Kim Chapman via C320-list <c320...@lists.catalina320.com> wrote:
>
> Have you tried giving it a bunch of throttle when it's even a bit cold. My

[Daniel Kolean via C320-list]

Exactly as you stated, try it and let me know.
Dan
ENRICH Holland MI # 498
Sent from my iPhone

> On Jul 7, 2024, at 8:14 PM, Wandering Star via C320-list <c320...@lists.catalina320.com> wrote:
>
> Louis,

[Daniel Kolean via C320-list]

Looks like Kim C uses the same method.
Sent from my iPhone

> On Jul 8, 2024, at 1:44 PM, Daniel Kolean <dkol...@gmail.com> wrote:
>
> Exactly as you stated, try it and let me know.

[Louis Friedman via C320-list]

Kim, you open the throttle before starting the engine also?

--
Louis Friedman, DO, FACP
Woodbridge Medical Associates
www.woodbridgemed.com

732-634-0036

[Kim Chapman via C320-list]

Yeah, maybe 1/2 to 3/4 throttle and be ready to throttle back as soon as
she starts !

Kim

On Mon, Jul 8, 2024 at 2:01 PM Louis Friedman via C320-list <

[Robert Dean via C320-list]

There was a Service Advisory issued by Yanmar on Nov 1 2000 that addressed a similar problem. Call Yanmar for details.