Engine help
11-23-2007 | 09:44 AM
#41
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From: Houston
Knock sensors will not set a history code unless thay have failed. By the look of your pistons it appears that the scoring may have been do to irregular heating. Normaly when we see detonation damge due to uneven combustion over the top of the piston we see actual physical damge across the top of the piston before it takes out the side or ring area. The problom is more prevalent on cast then forged pistons. I think the 555 marine pcm has the capabilty to look at spark advance per each cyl and how it relates throughout the power curve, providing you have the diagnostic software. Take a good look at *CYL IN-LIENMENT> IE>injector pulswidth which is the amplitude and the duration of the injector or how long between on and off. Is the injector spary pattern what it should be? It should be conical in shape. Check for the right fuel pressure and the right fuel trim. Fuel trim is set by the PCM and is always changing. all these factors can be undetecbale by the boat operator but can lead to piston failure. Both the auto and marine indystries are very concerned on how FUEL BLEND CHANGES are going to affect their non FLEX-FUEL engines and fuel systems. And like I said prior>detonation in todays cars is becomeing a bigger and bigger problom even when the fuel mgt sys is working. Now we are seeing the same thing in marine engines
11-23-2007 | 10:47 AM
#42
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From: League City, TX.
Next time you fill up look at the lables on the pumps. Their
should be lables that indicate ethanol content. Ethanol below
10% is o.k. E-85 which Wallmart sells is 85% ethanol and 20% gasoline. If you are not driving a flex fuel vehicle you can not use E-85 without damaging your fuel sys. The next time
you refuel with Diesel their should be decals on the pump
stating the details on the fuel. Regarding Marine and Agg
fuel. Some fuel docks and Agg fuel retailers are still selling
low sulpher red die diesel. However as of a year ago the sulpher content in diesel is becoming less and less.
As I said low-low sulpher diesel produces less energy and
even less lubrication properties. The ethanol content in marine gas is even more of a question. I do not think fuel
docks have to state fuel content data. I am sure it is at least
10% ethanol.
should be lables that indicate ethanol content. Ethanol below
10% is o.k. E-85 which Wallmart sells is 85% ethanol and 20% gasoline. If you are not driving a flex fuel vehicle you can not use E-85 without damaging your fuel sys. The next time
you refuel with Diesel their should be decals on the pump
stating the details on the fuel. Regarding Marine and Agg
fuel. Some fuel docks and Agg fuel retailers are still selling
low sulpher red die diesel. However as of a year ago the sulpher content in diesel is becoming less and less.
As I said low-low sulpher diesel produces less energy and
even less lubrication properties. The ethanol content in marine gas is even more of a question. I do not think fuel
docks have to state fuel content data. I am sure it is at least
10% ethanol.
11-24-2007 | 07:33 AM
#43
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From: Seabrook, Tx
Frank, we did fuel pressure test while running during the sea trial. Everything checked out. The damaged pistons were definetly around the edge. According to what I have been told that is usually a lean fuel issue. If it is a more central location on the top of the piston, it is a hot spot caused by carbon build up.
Gerrit
Gerrit
11-25-2007 | 08:36 AM
#44
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From: League City, TX.
No dout it was a lien problom. fuel pressure is the measurement of what the fuel pumps are generating and sending to the injectors. The injectors open and close, this is
caused injector pulse width. Pulse width and timing is dictated soley by the marine pcm, it is an output function. The input functions that the pcm uses to regulate pulse width come from specific sensors like throttle position (TPS), engine temp(ECT), manifold absolute pressure (MAP,Load identifier), crank sensor (CKS indicates rotation). Cam sensor (CMS mainly used for starting index) and the knock sensor. IAC (idle air control) is an output function O/2 sensors are not used on marine apps (yet). When all is working the engine is running at what we call stoichiometric or perfect theoretical combustion. However, probloms like bad injectors, vacuum leaks, heat, primary ign (the low voltage ign like the module, secondary ign (the high KV components like coils, plug wires and plugs) and fuel blends can cause cyl lien out and the PCM may not adjust for them. Thus you have engine damage like burned pistons, and scored cyls.
caused injector pulse width. Pulse width and timing is dictated soley by the marine pcm, it is an output function. The input functions that the pcm uses to regulate pulse width come from specific sensors like throttle position (TPS), engine temp(ECT), manifold absolute pressure (MAP,Load identifier), crank sensor (CKS indicates rotation). Cam sensor (CMS mainly used for starting index) and the knock sensor. IAC (idle air control) is an output function O/2 sensors are not used on marine apps (yet). When all is working the engine is running at what we call stoichiometric or perfect theoretical combustion. However, probloms like bad injectors, vacuum leaks, heat, primary ign (the low voltage ign like the module, secondary ign (the high KV components like coils, plug wires and plugs) and fuel blends can cause cyl lien out and the PCM may not adjust for them. Thus you have engine damage like burned pistons, and scored cyls.
11-25-2007 | 04:47 PM
#45
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I had my first CMI failure the end of 2006. $20k for a new header and long block and I got the boat back in Aug 2007. FOUR hours later, the new header failed at the weld and the motor bent a rod. Quite obviously caused by the header. CMI is blaming the silent choice, which is factory installed so now I waiting on Baja's response. My dealer (also a Fountain Dealer) has a PILE of 525 blocks and headers that have failed! No one seems to want to warranty anything, but what to do since they have not even seemed to have fixed the problem. A proper weld should actually be stronger than the material is is connecting so I believe CMI is at fault. Anyone know of an alternate header I can put on?
11-25-2007 | 06:33 PM
#47
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From: League City, TX.
I had my first CMI failure the end of 2006. $20k for a new header and long block and I got the boat back in Aug 2007. FOUR hours later, the new header failed at the weld and the motor bent a rod. Quite obviously caused by the header. CMI is blaming the silent choice, which is factory installed so now I waiting on Baja's response. My dealer (also a Fountain Dealer) has a PILE of 525 blocks and headers that have failed! No one seems to want to warranty anything, but what to do since they have not even seemed to have fixed the problem. A proper weld should actually be stronger than the material is is connecting so I believe CMI is at fault. Anyone know of an alternate header I can put on?
good luck
11-25-2007 | 07:24 PM
#48
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Posts: 441
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From: Canton,Michigan
I blew a motor in my lift. Started it up after sitting for 2 months and was missing terrible. Did a leak down and no 8 cylinder had no pressure. Pressure tested headers and Both CMI headers were leaking on that motor. 05 Donzi 38ZR. Had my dealer ship to merc for rebuild from Florida to Wisconsin and they didn't winterize the block. It was frozen solid, i.e. junk by the time it got there. Now have a new long block for the motor drain the headers before any storage time. 1 year and no prblems yet!
11-26-2007 | 09:57 AM
#49
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From: Houston
I blew a motor in my lift. Started it up after sitting for 2 months and was missing terrible. Did a leak down and no 8 cylinder had no pressure. Pressure tested headers and Both CMI headers were leaking on that motor. 05 Donzi 38ZR. Had my dealer ship to merc for rebuild from Florida to Wisconsin and they didn't winterize the block. It was frozen solid, i.e. junk by the time it got there. Now have a new long block for the motor drain the headers before any storage time. 1 year and no prblems yet!
What part of Fla are you? Fresh or salt water? Who is your dealer?
Last edited by On Time; 11-26-2007 at 12:54 PM.
11-26-2007 | 03:52 PM
#50
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Joined: Jun 2005
Posts: 441
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From: Canton,Michigan
Beak,
I have 525's in a staggered installation. The leaks were at the collector plate and were repaired by CMI. The headers on my boat are custom so they are not warrantied by CMI/mercury but Donzi. I boat in Ft Myers Beach Florida Salt Water in the winter and Detroit, MI Lake St CLair Freshwater in the summer. Motors are always flushed with saltaway after each use. Both sets of headers on my boat leaked at the same location. I have not had any problems since the leaks were welded by CMI. If I know the boat is going to sit for any time more than a day or 2, I drain the headers and leave the plugs out. It's easy in my motor box with the stagger. etting close to rebuild time on one motor and I will have the headers tested at that time.
Hope this helps.
Mark
I have 525's in a staggered installation. The leaks were at the collector plate and were repaired by CMI. The headers on my boat are custom so they are not warrantied by CMI/mercury but Donzi. I boat in Ft Myers Beach Florida Salt Water in the winter and Detroit, MI Lake St CLair Freshwater in the summer. Motors are always flushed with saltaway after each use. Both sets of headers on my boat leaked at the same location. I have not had any problems since the leaks were welded by CMI. If I know the boat is going to sit for any time more than a day or 2, I drain the headers and leave the plugs out. It's easy in my motor box with the stagger. etting close to rebuild time on one motor and I will have the headers tested at that time.
Hope this helps.
Mark
