Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop

[John and Maryann Read via CnC-List]

Exhaust elbow

 

 

John and Maryann

Legacy III

1982 C&C 34

Noank, CT

 

 

 

From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Eugene Fodor 
via CnC-List
Sent: Saturday, August 17, 2019 8:14 PM
To: cnc-list
Cc: Eugene Fodor
Subject: Stus-List Yanmar 2GMF losing power under load/RPMs drop

 

My 2GMF 13HP on my 29 mk 2 is dropping RPMs at max throttle under load. It also 
appears to drift a bit while operating at a fixed throttle. Tied at the dock 
forward seems to have more difficulty that reverse. I should be able to get up 
to 3200-3400 RPM (and have been able to in recent times with no issue, but I'm 
only getting to about 2500-2800. When I open the throttle wide it in gear it 
initially goes to high RPMs and then drops back. I replaced the fuel filter and 
the symptom remains the same. Any thoughts on what to look for and approaches 
to debug? 

 

I've got the service manual and Don Casey's book on small engines, but nothing 
is matching the symptoms in trouble shooting exactly well.

 

So my theories are (in approximate order of suspicion from my novice 
perspective based on reading)

 

Governor is faulty and needs adjustment

Injector faulty

Fuel pump issue

Air/water in fuel (I think I've mostly ruled this out)

 

 

___

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Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop

[Bill via CnC-List]

Maybe group in the pickup tube? Try disconnecting it and blowing it outBill ColemanOn Aug 17, 2019 8:13 PM, Eugene Fodor via CnC-List  wrote:My 2GMF 13HP on my 29 mk 2 is dropping RPMs at max throttle under load. It also appears to drift a bit while operating at a fixed throttle. Tied at the dock forward seems to have more difficulty that reverse. I should be able to get up to 3200-3400 RPM (and have been able to in recent times with no issue, but I'm only getting to about 2500-2800. When I open the throttle wide it in gear it initially goes to high RPMs and then drops back. I replaced the fuel filter and the symptom remains the same. Any thoughts on what to look for and approaches to debug? I've got the service manual and Don Casey's book on small engines, but nothing is matching the symptoms in trouble shooting exactly wellSo my theories are (in approximate order of suspicion from my novice perspective based on reading)Governor is faulty and needs adjustmentInjector faultyFuel pump issueAir/water in fuel (I think I've mostly ruled this out) 
___

Thanks everyone for supporting this list with your contributions.  Each and 
every one is greatly appreciated.  If you want to support the list - use PayPal 
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Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop

[Luke Wolbrink via CnC-List]

I recently had a similar issue where the engine would drop RPM's under load
and eventaully stumble and die. It ended up being the fuel lift pump was on
it's last legs and just not getting enough fuel to the high pressure pump
once the fuel level in the tank was low enough not to just siphon. Instead
of replacing with a yanmar part for $$$ I bought an electric fuel pump on
amazon for under $20 and wired it into the key switch, works perfect and
not more problems.

hope that helps.

~Luke
SV Zella 1985 35-3

On Sun, Aug 18, 2019 at 9:29 AM  wrote:

> Send CnC-List mailing list submissions to
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> Today's Topics:
>
>1.  Yanmar 2GMF losing power under load/RPMs drop (Eugene Fodor)
>2. Re:  Yanmar 2GMF losing power under load/RPMs drop (Robert Boyer)
>3. Re:  Yanmar 2GMF losing power under load/RPMs drop (Eugene Fodor)
>4. Re:  Yanmar 2GMF losing power under load/RPMs drop
>   (Jeff Helsdingen)
>5. Re:  Yanmar 2GMF losing power under load/RPMs drop (ALAN BERGEN)
>6. Re:  Yanmar 2GMF losing power under load/RPMs drop (Paul Baker)
>7. Re:  Yanmar 2GMF losing power under load/RPMs drop
>   (John and Maryann Read)
>8. Re:  Yanmar 2GMF losing power under load/RPMs drop (Bill)
>
>
>
> -- Forwarded message --
> From: Eugene Fodor 
> To: cnc-list 
> Cc:
> Bcc:
> Date: Sat, 17 Aug 2019 19:13:31 -0500
> Subject: Stus-List Yanmar 2GMF losing power under load/RPMs drop
> My 2GMF 13HP on my 29 mk 2 is dropping RPMs at max throttle under load. It
> also appears to drift a bit while operating at a fixed throttle. Tied at
> the dock forward seems to have more difficulty that reverse. I should be
> able to get up to 3200-3400 RPM (and have been able to in recent times with
> no issue, but I'm only getting to about 2500-2800. When I open the throttle
> wide it in gear it initially goes to high RPMs and then drops back. I
> replaced the fuel filter and the symptom remains the same. Any thoughts on
> what to look for and approaches to debug?
>
> I've got the service manual and Don Casey's book on small engines, but
> nothing is matching the symptoms in trouble shooting exactly well.
>
> So my theories are (in approximate order of suspicion from my novice
> perspective based on reading)
>
> Governor is faulty and needs adjustment
> Injector faulty
> Fuel pump issue
> Air/water in fuel (I think I've mostly ruled this out)
>
>
>
>
>
> -- Forwarded message --
> From: Robert Boyer 
> To: cnc-list@cnc-list.com
> Cc: Eugene Fodor 
> Bcc:
> Date: Sat, 17 Aug 2019 20:27:57 -0400
> Subject: Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop
> While this may not help you with your diesel issue, in the 36 years that I
> have owned my boat, I have never even tried to achieve RPMs above about
> 2800.  I can achieve hull speed at 2600 RPMs and I generally cruise at 2400
> RPM.
>
> Bob Boyer
> s/v Rainy Days
> C&C Landfall 38 (Hull # 230)
> (Presently in Baltimore for the summer)
> blog: dainyrays.blogspot.com
> email: dainyr...@icloud.com
>
> > On Aug 17, 2019, at 8:13 PM, Eugene Fodor via CnC-List <
> cnc-list@cnc-list.com> wrote:
> >
> > My 2GMF 13HP on my 29 mk 2 is dropping RPMs at max throttle under load.
> It also appears to drift a bit while operating at a fixed throttle. Tied at
> the dock forward seems to have more difficulty that reverse. I should be
> able to get up to 3200-3400 RPM (and have been able to in recent times with
> no issue, but I'm only getting to about 2500-2800. When I open the throttle
> wide it in gear it initially goes to high RPMs and then drops back. I
> replaced the fuel filter and the symptom remains the same. Any thoughts on
> what to look for and approaches to debug?
> >
> > I've got the service manual and Don Casey's book on small engines, but
> nothing is matching the symptoms in trouble shooting exactly well.
> >
> > So my theories are (in approximate order of suspicion from my novice
> perspective based on reading)
> >
> > Governor is faulty and needs adjustment
> > Injector faulty
> > Fuel pump issue
> > Air/water in fuel (I think I've mostly ruled this out)
> >
> >
> > ___
> >
> > Thanks everyone for supporting this list with your contributions.  Each
> and every one is greatly appreciated.  If you want to support the list -
> use PayPal to send contribution --   https://www.paypal.me/stumurray
> >
>
>
>
>
>
>
> -- Forwarded message --
> From: Eugene Fodor 
> To: Robert Boyer , cnc-list 
> Cc:
> Bcc:
> Date:

Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop

[David Risch via CnC-List]

You may want to replace the lift pump.anyway  and use the electric pump as 
backup and for bleeding.

From: CnC-List  on behalf of Luke Wolbrink via 
CnC-List 
Sent: Sunday, August 18, 2019 10:42:42 AM
To: cnc-list@cnc-list.com 
Cc: Luke Wolbrink 
Subject: Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop

I recently had a similar issue where the engine would drop RPM's under load and 
eventaully stumble and die. It ended up being the fuel lift pump was on it's 
last legs and just not getting enough fuel to the high pressure pump once the 
fuel level in the tank was low enough not to just siphon. Instead of replacing 
with a yanmar part for $$$ I bought an electric fuel pump on amazon for under 
$20 and wired it into the key switch, works perfect and not more problems.

hope that helps.

~Luke
SV Zella 1985 35-3

On Sun, Aug 18, 2019 at 9:29 AM 
mailto:cnc-list-requ...@cnc-list.com>> wrote:
Send CnC-List mailing list submissions to
cnc-list@cnc-list.com

To subscribe or unsubscribe via the World Wide Web, visit
http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
or, via email, send a message with subject or body 'help' to
cnc-list-requ...@cnc-list.com

You can reach the person managing the list at
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When replying, please edit your Subject line so it is more specific
than "Re: Contents of CnC-List digest..."
Today's Topics:

   1.  Yanmar 2GMF losing power under load/RPMs drop (Eugene Fodor)
   2. Re:  Yanmar 2GMF losing power under load/RPMs drop (Robert Boyer)
   3. Re:  Yanmar 2GMF losing power under load/RPMs drop (Eugene Fodor)
   4. Re:  Yanmar 2GMF losing power under load/RPMs drop
  (Jeff Helsdingen)
   5. Re:  Yanmar 2GMF losing power under load/RPMs drop (ALAN BERGEN)
   6. Re:  Yanmar 2GMF losing power under load/RPMs drop (Paul Baker)
   7. Re:  Yanmar 2GMF losing power under load/RPMs drop
  (John and Maryann Read)
   8. Re:  Yanmar 2GMF losing power under load/RPMs drop (Bill)



-- Forwarded message --
From: Eugene Fodor mailto:efo...@gmail.com>>
To: cnc-list mailto:cnc-list@cnc-list.com>>
Cc:
Bcc:
Date: Sat, 17 Aug 2019 19:13:31 -0500
Subject: Stus-List Yanmar 2GMF losing power under load/RPMs drop
My 2GMF 13HP on my 29 mk 2 is dropping RPMs at max throttle under load. It also 
appears to drift a bit while operating at a fixed throttle. Tied at the dock 
forward seems to have more difficulty that reverse. I should be able to get up 
to 3200-3400 RPM (and have been able to in recent times with no issue, but I'm 
only getting to about 2500-2800. When I open the throttle wide it in gear it 
initially goes to high RPMs and then drops back. I replaced the fuel filter and 
the symptom remains the same. Any thoughts on what to look for and approaches 
to debug?

I've got the service manual and Don Casey's book on small engines, but nothing 
is matching the symptoms in trouble shooting exactly well.

So my theories are (in approximate order of suspicion from my novice 
perspective based on reading)

Governor is faulty and needs adjustment
Injector faulty
Fuel pump issue
Air/water in fuel (I think I've mostly ruled this out)





-- Forwarded message --
From: Robert Boyer mailto:dainyr...@icloud.com>>
To: cnc-list@cnc-list.com
Cc: Eugene Fodor mailto:efo...@gmail.com>>
Bcc:
Date: Sat, 17 Aug 2019 20:27:57 -0400
Subject: Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop
While this may not help you with your diesel issue, in the 36 years that I have 
owned my boat, I have never even tried to achieve RPMs above about 2800.  I can 
achieve hull speed at 2600 RPMs and I generally cruise at 2400 RPM.

Bob Boyer
s/v Rainy Days
C&C Landfall 38 (Hull # 230)
(Presently in Baltimore for the summer)
blog: dainyrays.blogspot.com
email: dainyr...@icloud.com

> On Aug 17, 2019, at 8:13 PM, Eugene Fodor via CnC-List 
> mailto:cnc-list@cnc-list.com>> wrote:
>
> My 2GMF 13HP on my 29 mk 2 is dropping RPMs at max throttle under load. It 
> also appears to drift a bit while operating at a fixed throttle. Tied at the 
> dock forward seems to have more difficulty that reverse. I should be able to 
> get up to 3200-3400 RPM (and have been able to in recent times with no issue, 
> but I'm only getting to about 2500-2800. When I open the throttle wide it in 
> gear it initially goes to high RPMs and then drops back. I replaced the fuel 
> filter and the symptom remains the same. Any thoughts on what to look for and 
> approaches to debug?
>
> I've got the service manual and Don Casey's book on small engines, but 
> nothing is matching the symptoms in trouble shooting exactly well.
>
> So my theories are (in approximate order of suspicion from my novice 
> perspective based on rea

Re: Stus-List Hitachi 55A alternator question - 12.63 v output...

[sender via CnC-List]

Dave:
Since you're getting low voltage between the batt terminal and the
alternator casing, it does sound irrefutable, it's kicking the bucket.

You can remove your alternator and take it to an auto-electric shop.  New
electronic module and bearings and you have a good as new rebuilt
alternator.  They're not as common as they used to be, but they specialize
in repairs and re-building starters and alternators.  If you know anyone
with the classic car bug, they would likely be able point you in the right
direction.  There are cheaper options from auto parts stores, but I'd
strongly recommend rebuilding it or replacing it with another Hitachi
alternator.

Eric

On Fri, Aug 9, 2019 at 1:41 PM Dave S via CnC-List 
wrote:

> Hi All,
>
> I have a yanmar 2GMf20 with what I believe is the stock 55 amp
> alternator.   I noticed that my ACR was not combining batteries, which led
> me to research a bit then measure the voltages on each bank, and then at
> the alternator “Batt” terminal.
>
> Irrespective or RPM or battery state, the voltage at the BATT terminal
> does not exceed 12.63 in operation.   (he ACR therefore doesn’t “see” a
> charging state)  The belt is new and not slipping.
>
> This suggests and alternator or regulator problem.   Does this make
> sense?  Is there anything else I should check?
>
> If I end up replacing the regulator, are there better options for this
> alternator than stock?
>
>
>
> Thanks All.
>
>
>
> Dave
>
>
>
>
>
>
>
> Sent from Mail  for
> Windows 10
>
>
> ___
>
> Thanks everyone for supporting this list with your contributions.  Each
> and every one is greatly appreciated.  If you want to support the list -
> use PayPal to send contribution --   https://www.paypal.me/stumurray
>
>
___

Thanks everyone for supporting this list with your contributions.  Each and 
every one is greatly appreciated.  If you want to support the list - use PayPal 
to send contribution --   https://www.paypal.me/stumurray