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 <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 > cnc-list-ow...@cnc-list.com > > 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 <efo...@gmail.com> > To: cnc-list <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 <dainyr...@icloud.com> > To: cnc-list@cnc-list.com > Cc: Eugene Fodor <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 < > 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 <efo...@gmail.com> > To: Robert Boyer <dainyr...@icloud.com>, cnc-list <cnc-list@cnc-list.com> > Cc: > Bcc: > Date: Sat, 17 Aug 2019 20:19:58 -0500 > Subject: Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop > Yeah, unfortunately that doesn't help, in forward gear I'm not even > consistently hitting 2800 (more like 25-26). I've been able to get up to > 3600 so something is definitely wrong and has changed for the worse. Also, > prop and shaft look fine. I dove the boat while we were out and it all > checks out. My boat hits hull speed around 28-29 in calm water. > > Gene Fodor > s/v Hawk > C&C 29 mk 2 > > On Sat, Aug 17, 2019 at 7:28 PM Robert Boyer <dainyr...@icloud.com> wrote: > >> 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 >> >> > > > ---------- Forwarded message ---------- > From: Jeff Helsdingen <onemorej...@gmail.com> > To: cnc-list@cnc-list.com > Cc: > Bcc: > Date: Sat, 17 Aug 2019 21:51:32 -0400 > Subject: Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop > Possibly the exhaust mixing elbow is getting clogged up? > > On Sat, Aug 17, 2019 at 9:20 PM Eugene Fodor via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Yeah, unfortunately that doesn't help, in forward gear I'm not even >> consistently hitting 2800 (more like 25-26). I've been able to get up to >> 3600 so something is definitely wrong and has changed for the worse. Also, >> prop and shaft look fine. I dove the boat while we were out and it all >> checks out. My boat hits hull speed around 28-29 in calm water. >> >> Gene Fodor >> s/v Hawk >> C&C 29 mk 2 >> >> On Sat, Aug 17, 2019 at 7:28 PM Robert Boyer <dainyr...@icloud.com> >> wrote: >> >>> 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 >>> >>> _______________________________________________ >> >> 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: ALAN BERGEN <trya...@alumni.usc.edu> > To: "C&C" <cnc-list@cnc-list.com> > Cc: > Bcc: > Date: Sat, 17 Aug 2019 18:56:07 -0700 > Subject: Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop > It could be your mixing elbow. Remove it and see whether it's clogged. If > yes, you can scrape it out, or have a radiator shop boil it out. > > Alan Bergen > 35 Mk III Thirsty > Rose City YC > Portland, OR > > On Sat, Aug 17, 2019 at 5:14 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://urldefense.proofpoint.com/v2/url?u=https-3A__www.paypal.me_stumurray&d=DwICAg&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=9w3G7Cf8YfQnrjmtuNxwDJYr3JMv9f1pAfgAJ9xXYQQ&m=J7yR_wioiYdv_W5vUkFkJJXcELH0RCiI3zMJI2QdlOM&s=MzpJcmBodkNtQt6LCSMy7duJv46NR659jwqyhr-gyzo&e= >> >> > > > ---------- Forwarded message ---------- > From: Paul Baker <pjbake...@hotmail.com> > To: cnc-list <cnc-list@cnc-list.com> > Cc: > Bcc: > Date: Sun, 18 Aug 2019 05:42:03 +0000 > Subject: Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop > Any smoke while this is happening? > > ------------------------------ > *From:* CnC-List <cnc-list-boun...@cnc-list.com> on behalf of Eugene > Fodor via CnC-List <cnc-list@cnc-list.com> > *Sent:* August 17, 2019 5:13 PM > *To:* cnc-list <cnc-list@cnc-list.com> > *Cc:* Eugene Fodor <efo...@gmail.com> > *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: John and Maryann Read <johnprea...@gmail.com> > To: <cnc-list@cnc-list.com> > Cc: > Bcc: > Date: Sun, 18 Aug 2019 07:05:31 -0400 > Subject: Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop > > 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) > > > > > > > > ---------- Forwarded message ---------- > From: Bill <colt...@verizon.net> > To: cnc-list@cnc-list.com > Cc: > Bcc: > Date: Sun, 18 Aug 2019 10:28:44 -0400 > Subject: Re: Stus-List Yanmar 2GMF losing power under load/RPMs drop > Maybe group in the pickup tube? Try disconnecting it and blowing it out > > Bill Coleman > > On Aug 17, 2019 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) > > > > > _______________________________________________ > CnC-List mailing list > CnC-List@cnc-list.com > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com >
_______________________________________________ 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
