Diesel Exhaust Pipe Blocked

A few weeks back I experienced a gradual loss of power from my Perkins 4108 diesel as we transited the canal out to the harbor. I turned back and barely made it to my dock as the engine could only turn at a max of 500rpm and was spitting raw diesel out the exhaust. My diesel mechanic took only 5 minutes to diagnose it. Said he sees this frequently with sailboats because they are never revved up to max rpm like powerboats. The cause was a blockage in the exhaust pipe at the U-shaped fitting where the raw water is injected. The pipe was filled with carbon and rust at the bend point and had to be replaced. I thought I would share this with the group and repeat his recommendation which is to run the engine at max rpm for at least 5 minutes on each cruise. I'm wondering how common this really is or if its only common here because we have 45 minute long canal journeys at near-idle speeds to get to the harbor entrance. I'm concerned about running at max rpm so often given the reputed tenderness of the Hurth transmission. Any thoughts ? Jim Hayes Cal34 MKII "Eos"

Diesel engines do need to be run hard,with a load. I wouldn't think Max RPM is required. I never run mine unless I can get it up to operating temps. A cool down period is also required after a hard run. 2-34 Seond Fiddle Ventura Ca From: zinbad3 <zi… [at] yahoo.com> To: Ca… [at] yahoogroups.com Sent: Wednesday, February 22, 2012 7:35 AM Subject: [Cal_Boats] Diesel Exhaust Pipe Blocked A few weeks back I experienced a gradual loss of power from my Perkins 4108 diesel as we transited the canal out to the harbor. I turned back and barely made it to my dock as the engine could only turn at a max of 500rpm and was spitting raw diesel out the exhaust. My diesel mechanic took only 5 minutes to diagnose it. Said he sees this frequently with sailboats because they are never revved up to max rpm like powerboats. The cause was a blockage in the exhaust pipe at the U-shaped fitting where the raw water is injected. The pipe was filled with carbon and rust at the bend point and had to be replaced. I thought I would share this with the group and repeat his recommendation which is to run the engine at max rpm for at least 5 minutes on each cruise. I'm wondering how common this really is or if its only common here because we have 45 minute long canal journeys at near-idle speeds to get to the harbor entrance. I'm concerned about running at max rpm so often given the reputed tenderness of the Hurth transmission. Any thoughts ? Jim Hayes Cal34 MKII "Eos"

Read about this problem more than a few times on cruisersforum. Joe just did a short write up not too long ago on this list which touched on the exhaust manifold: http://groups.yahoo.com/group/Cal_Boats/message/31260 I checked my elbow last year after a few years of running. No carbon build up, light surface rust. But I think I'm an exception. To go sailing on the lake it's a mile run under power, which I do at the cruising rpm for my engine (2900 Yanmar 3GM30. 1-2 hours motoring depending on the locks to get to salt water, again mostly at cruising rpm. Mooring in fresh water probably makes a difference at least for the corrosion issues. John From: zinbad3 <zi… [at] yahoo.com> To: Ca… [at] yahoogroups.com Sent: Wednesday, February 22, 2012 7:35 AM Subject: [Cal_Boats] Diesel Exhaust Pipe Blocked A few weeks back I experienced a gradual loss of power from my Perkins 4108 diesel as we transited the canal out to the harbor. I turned back and barely made it to my dock as the engine could only turn at a max of 500rpm and was spitting raw diesel out the exhaust. My diesel mechanic took only 5 minutes to diagnose it. Said he sees this frequently with sailboats because they are never revved up to max rpm like powerboats. The cause was a blockage in the exhaust pipe at the U-shaped fitting where the raw water is injected. The pipe was filled with carbon and rust at the bend point and had to be replaced. I thought I would share this with the group and repeat his recommendation which is to run the engine at max rpm for at least 5 minutes on each cruise. I'm wondering how common this really is or if its only common here because we have 45 minute long canal journeys at near-idle speeds to get to the harbor entrance. I'm concerned about running at max rpm so often given the reputed tenderness of the Hurth transmission. Any thoughts ? Jim Hayes Cal34 MKII "Eos"

We had had our Cal 33 with a yanmar 3gm30f for about 5 years, when I had a problem with the water injection into the elbow. The water side had rusted enough to build up some blockage over the ¼” pipe thread fitting. A sharp screw driver removed the blockage, but I lost confidence in the integrity of the elbow. I talked to the local yanmar mechanic, along with a photo of the elbow, rust spots and all. He said yanmar recommended replacing the elbow, every 5 years. Some due to carbon build up, and the possibility of the separation between the water injection and exhaust rusting completely through. If this happened, water could possibly get injected into the exhaust side, and backflow into the head and cylinders. Of course, I think yanmar recommends replacing all their parts every 5 years or so. We have had ours problem free for another 10 years so far. We only costal cruise, weekends and no off shore where tow boat isn’t more than 2 hours away, so replacements are more in failure mode rather than preventive maintenance. Ymmv john From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] On Behalf Of zinbad3 Sent: Wednesday, February 22, 2012 10:36 AM To: Ca… [at] yahoogroups.com Subject: [Cal_Boats] Diesel Exhaust Pipe Blocked A few weeks back I experienced a gradual loss of power from my Perkins 4108 diesel as we transited the canal out to the harbor. I turned back and barely made it to my dock as the engine could only turn at a max of 500rpm and was spitting raw diesel out the exhaust. My diesel mechanic took only 5 minutes to diagnose it. Said he sees this frequently with sailboats because they are never revved up to max rpm like powerboats. The cause was a blockage in the exhaust pipe at the U-shaped fitting where the raw water is injected. The pipe was filled with carbon and rust at the bend point and had to be replaced. I thought I would share this with the group and repeat his recommendation which is to run the engine at max rpm for at least 5 minutes on each cruise. I'm wondering how common this really is or if its only common here because we have 45 minute long canal journeys at near-idle speeds to get to the harbor entrance. I'm concerned about running at max rpm so often given the reputed tenderness of the Hurth transmission. Any thoughts ? Jim Hayes Cal34 MKII "Eos"

John, Even though this is a Perkins installation, it turned out that the elbow was a yanmar part. And the water side had rusted and was nearly blocked by rust. There was only a hole less than the diameter of a pencil remaining for the saltwater to enter the exhaust pipe. Seems that everyone should check this part out periodically, especially in salt water environments. Jim Hayes Cal34 MKII 'Eos' --- In Ca… [at] yahoogroups.com, "john raxter" <jraxter@...> wrote: > > We had had our Cal 33 with a yanmar 3gm30f for about 5 years, when I had a > problem with the water injection into the elbow. The water side had rusted > enough to build up some blockage over the ¼" pipe thread fitting. A sharp > screw driver removed the blockage, but I lost confidence in the integrity of > the elbow. I talked to the local yanmar mechanic, along with a photo of the > elbow, rust spots and all. He said yanmar recommended replacing the elbow, > every 5 years. Some due to carbon build up, and the possibility of the > separation between the water injection and exhaust rusting completely > through. If this happened, water could possibly get injected into the > exhaust side, and backflow into the head and cylinders. > > > > Of course, I think yanmar recommends replacing all their parts every 5 years > or so. We have had ours problem free for another 10 years so far. We only > costal cruise, weekends and no off shore where tow boat isn't more than 2 > hours away, so replacements are more in failure mode rather than preventive > maintenance. > > > > Ymmv > > > > john > > > > From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] On Behalf > Of zinbad3 > Sent: Wednesday, February 22, 2012 10:36 AM > To: Ca… [at] yahoogroups.com > Subject: [Cal_Boats] Diesel Exhaust Pipe Blocked > > > > > > A few weeks back I experienced a gradual loss of power from my Perkins 4108 > diesel as we transited the canal out to the harbor. I turned back and barely > made it to my dock as the engine could only turn at a max of 500rpm and was > spitting raw diesel out the exhaust. > My diesel mechanic took only 5 minutes to diagnose it. Said he sees this > frequently with sailboats because they are never revved up to max rpm like > powerboats. The cause was a blockage in the exhaust pipe at the U-shaped > fitting where the raw water is injected. The pipe was filled with carbon and > rust at the bend point and had to be replaced. > I thought I would share this with the group and repeat his recommendation > which is to run the engine at max rpm for at least 5 minutes on each cruise. > I'm wondering how common this really is or if its only common here because > we have 45 minute long canal journeys at near-idle speeds to get to the > harbor entrance. I'm concerned about running at max rpm so often given the > reputed tenderness of the Hurth transmission. Any thoughts ? > Jim Hayes > Cal34 MKII "Eos" >

I had to replace the exhaust elbow on my Yanmar 3GM when I replaced the intake pump. That was 2 years ago so the elbow was 24 years old! I think the lack of flow through the elbow put enough stress on the pump as to cause it to fail. I will now check the elbow more often to make sure the flow is not restricted. Although, now we are on freshwater and the problem should not be as much an issue! Don Dutton, 1986 Cal 33-2, "Quantum Evolution" On Feb 23, 2012, at 5:35 AM, zinbad3 wrote: > > John, > Even though this is a Perkins installation, it turned out that the elbow was a yanmar part. And the water side had rusted and was nearly blocked by rust. There was only a hole less than the diameter of a pencil remaining for the saltwater to enter the exhaust pipe. > Seems that everyone should check this part out periodically, especially in salt water environments. > Jim Hayes > Cal34 MKII 'Eos' > > --- In Ca… [at] yahoogroups.com, "john raxter" <jraxter@...> wrote: > > > > We had had our Cal 33 with a yanmar 3gm30f for about 5 years, when I had a > > problem with the water injection into the elbow. The water side had rusted > > enough to build up some blockage over the ¼" pipe thread fitting. A sharp > > screw driver removed the blockage, but I lost confidence in the integrity of > > the elbow. I talked to the local yanmar mechanic, along with a photo of the > > elbow, rust spots and all. He said yanmar recommended replacing the elbow, > > every 5 years. Some due to carbon build up, and the possibility of the > > separation between the water injection and exhaust rusting completely > > through. If this happened, water could possibly get injected into the > > exhaust side, and backflow into the head and cylinders. > > > > > > > > Of course, I think yanmar recommends replacing all their parts every 5 years > > or so. We have had ours problem free for another 10 years so far. We only > > costal cruise, weekends and no off shore where tow boat isn't more than 2 > > hours away, so replacements are more in failure mode rather than preventive > > maintenance. > > > > > > > > Ymmv > > > > > > > > john > > > > > > > > From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] On Behalf > > Of zinbad3 > > Sent: Wednesday, February 22, 2012 10:36 AM > > To: Ca… [at] yahoogroups.com > > Subject: [Cal_Boats] Diesel Exhaust Pipe Blocked > > > > > > > > > > > > A few weeks back I experienced a gradual loss of power from my Perkins 4108 > > diesel as we transited the canal out to the harbor. I turned back and barely > > made it to my dock as the engine could only turn at a max of 500rpm and was > > spitting raw diesel out the exhaust. > > My diesel mechanic took only 5 minutes to diagnose it. Said he sees this > > frequently with sailboats because they are never revved up to max rpm like > > powerboats. The cause was a blockage in the exhaust pipe at the U-shaped > > fitting where the raw water is injected. The pipe was filled with carbon and > > rust at the bend point and had to be replaced. > > I thought I would share this with the group and repeat his recommendation > > which is to run the engine at max rpm for at least 5 minutes on each cruise. > > I'm wondering how common this really is or if its only common here because > > we have 45 minute long canal journeys at near-idle speeds to get to the > > harbor entrance. I'm concerned about running at max rpm so often given the > > reputed tenderness of the Hurth transmission. Any thoughts ? > > Jim Hayes > > Cal34 MKII "Eos" > > > >