Absolutely frustrated with this Mercruiser engine

Hoplite808 said:
Then proceeds to tell me he had an injury that caused hearing loss in one ear and now he hears low frequency noises really well, almost like a super power he claimed. He then says that he can hear a galloping noise from the bottom of the block and recommends a full engine replacement. I can't hear any such noise nor can I think of what on earth would make a "galloping" noise from the crank which he assures me only his special hearing ability would be able to hear.
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This is simply amazing :rolleyes: .

Maybe you can find a gay mechanic who sits on the engine while it runs because he developed a special sense and feel of a 'piston' working around his a$$ . Perhaps he can sense special vibrations a normal man cannot ? :D

Seriously :
Can you quickly haul the boat , put it on muffs and rev it sitting on the trailer in gear to see if the 2000rpm is about being in gear or really about the load ?
 
Hoplite808 said:
I took them to a shop and paid for them and a set of the Chinese ones from ebay I got for $150 to get tested. The shop said all 8 Mercruiser injectors were bad and the Chinese ones were tested OK. I installed the Chinese junk ones and the engine won't even try to run on them. It will however start and run well up to 2000 RPM's on the old Mercruiser ones. I am looking for another shop that actually knows what they are doing to test them. In the SEALOC repair manual it said to test for resistance across the terminals of each injector to see if they are ok and you should get a reading of 12 ohms +/- 0.04 if they are ok. I tested this and all 8 read 12 ohms exactly. I then took a 9volt battery and used it to trigger each injector while I sprayed carb cleaner through each injector and all 8 appeared to spray well. I know thats a janky thing to do but I'm trying everything at this point. The Mercruiser brand replacement injectors are between $300-400 each and 8 of them at this time would break the bank for me right now. If I can't find another shop that can test them properly then I'm going to have to wait until I can save up enough money to just buy 8 new ones.
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Right, I do remember that... that you got kinda hosed on that purchase. But there was discussion about sending them stateside to a shop via FedEx. Look back at our posts, but I think you had a question about shipping costs and that had got me curious as I never thought about shipping off the island. But I did (again, look back at the posts) do a shipping estimate and I think it was about $40?
 
Lazy Daze said:
Right, I do remember that... that you got kinda hosed on that purchase. But there was discussion about sending them stateside to a shop vis FedEx. Look back at our posts, but I think you had a question about shipping costs and that had got me curious as I never thought about shipping off the island. But I did (again, look back at the posts) do a shipping estimate and I think it was about $40?
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All the indications still point to the injectors except for the galloping horse diagnostic. Faulty injectors or a problem with the fuel rail/pressure won't show up on diagnostics. Essentially the engine continues to run out of gas above 2,000 rpm. Your Chinese injectors versus the OEM ones confirms the injectors are the most likely culprit.

Exactly what sensors could he see? Did he give you a print out of the engine at idle and another at wide open throttle?
 
@PlayDate he did not give me a printout but was showing me the info the whole time. There actually was quite a bit more data than I had expected. Oil pressure, temp, injector pulse, IAC, throttle position, timing advance, barometric, map, and data for alarms and the discrete switches in the MEFI 1 manual as well as any trouble codes. His computer could also tell it to reset everything too original factory settings and test the alarms. All the data Showed an engine that was running fine and within specified parameters. Going down today to pull the injectors out, again, and send them off to a competent person to test. Don’t know when I’ll get them back but God willing that will be what the issue is so I can fix it.
 
aerobat77 said:
This is simply amazing :rolleyes: .

Maybe you can find a gay mechanic who sits on the engine while it runs because he developed a special sense and feel of a 'piston' working around his a$$ . Perhaps he can sense special vibrations a normal man cannot ? :D

Seriously :
Can you quickly haul the boat , put it on muffs and rev it sitting on the trailer in gear to see if the 2000rpm is about being in gear or really about the load ?
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I could schedule a haul out at the one place on island that can but it would cost me $1000 and they could maybe get to me in several months since it’s not an emergency which of course would cost me more.
 
Hoplite808 said:
I could schedule a haul out at the one place on island that can but it would cost me $1000 and they could maybe get to me in several months since it’s not an emergency which of course would cost me more.
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It really seems all odds are against you ...

I must admit i,ve never heared a story where anything , really anything basicly simple to diagnose the culprit is a virtually unsolvable problem ...

Why not slip a 270 ?
 
Hoplite808 said:
@PlayDate he did not give me a printout but was showing me the info the whole time. There actually was quite a bit more data than I had expected. Oil pressure, temp, injector pulse, IAC, throttle position, timing advance, barometric, map, and data for alarms and the discrete switches in the MEFI 1 manual as well as any trouble codes. His computer could also tell it to reset everything too original factory settings and test the alarms. All the data Showed an engine that was running fine and within specified parameters. Going down today to pull the injectors out, again, and send them off to a competent person to test. Don’t know when I’ll get them back but God willing that will be what the issue is so I can fix it.
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That's good but I was hoping to actually see the numbers. Sometimes an extra set of eyes is a good thing. For example, I was interested in the engine timing as the RPMs increased and the injector pulse. Also whether the TPS was recording the throttle position correctly as well as the MAP working properly. Specifically....I wanted to see if the engine was retarded due to a timing chain issue. Its a long shot but if it jumped a tooth or someone changed it improperly at some point....that could also explain it. We have discussed all the relevant areas

If I take for granted that they were all operating correctly......then we are left again with pressure on the fuel rail and the injectors which the diagnostics don't help us with.

I would take the suggestion from others to send them to the mainland to be tested.

If the injectors don't solve it then I'm going to recommend what the galloping guy came up with.:)
 
Hoplite808 said:
@PlayDate he did not give me a printout but was showing me the info the whole time. There actually was quite a bit more data than I had expected. Oil pressure, temp, injector pulse, IAC, throttle position, timing advance, barometric, map, and data for alarms and the discrete switches in the MEFI 1 manual as well as any trouble codes. His computer could also tell it to reset everything too original factory settings and test the alarms. All the data Showed an engine that was running fine and within specified parameters. Going down today to pull the injectors out, again, and send them off to a competent person to test. Don’t know when I’ll get them back but God willing that will be what the issue is so I can fix it.
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PlayDate said:
That's good but I was hoping to actually see the numbers. Sometimes an extra set of eyes is a good thing. For example, I was interested in the engine timing as the RPMs increased and the injector pulse. Also whether the TPS was recording the throttle position correctly as well as the MAP working properly. Specifically....I wanted to see if the engine was retarded due to a timing chain issue. Its a long shot but if it jumped a tooth or someone changed it improperly at some point....that could also explain it. We have discussed all the relevant areas

If I take for granted that they were all operating correctly......then we are left again with pressure on the fuel rail and the injectors which the diagnostics don't help us with.

I would take the suggestion from others to send them to the mainland to be tested.

If the injectors don't solve it then I'm going to recommend what the galloping guy came up with.:)
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What were those compression numbers again?
Also, @Hoplite808 what is your manifold vacuum reading at idle?
 
@techmitch the cylinder pressure that I got from my cheap 20 year old compression gauge bought from Napa once upon a time was all cylinders within a few pounds of 125. The cylinder walls of all 8 cylinders were clean and free of visible wear damage. Per the computer the engine has only been run for a total of 566 hours in its lifetime so far. I don’t remember the exact numbers from the MAP while underway as I was driving the boat while the mechanic was watching all the numbers. But according to the mechanic and what I remember him showing me on his computer screen it was all within normal limits. I just finished pulling the injectors again. As soon as I can get them to a reputable technician to diagnose I won’t be able to start the engine for more info. I do have a Fox Marine gateway device ordered and once that gets here and I reinstall the injectors I should be able to take screenshots of the data on my phone to share if it’s still acting up.
 
Hoplite808 said:
@techmitch the cylinder pressure that I got from my cheap 20 year old compression gauge bought from Napa once upon a time was all cylinders within a few pounds of 125. The cylinder walls of all 8 cylinders were clean and free of visible wear damage. Per the computer the engine has only been run for a total of 566 hours in its lifetime so far. I don’t remember the exact numbers from the MAP while underway as I was driving the boat while the mechanic was watching all the numbers. But according to the mechanic and what I remember him showing me on his computer screen it was all within normal limits. I just finished pulling the injectors again. As soon as I can get them to a reputable technician to diagnose I won’t be able to start the engine for more info. I do have a Fox Marine gateway device ordered and once that gets here and I reinstall the injectors I should be able to take screenshots of the data on my phone to share if it’s still acting up.
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When you get her back together, if you still problems, (which I hope you don't but I suspect you will) take a manifold vacuum reading with a good mechanical vacuum gauge, they are inexpensive and good tool to have.
 
techmitch said:
When you get her back together, if you still problems, (which I hope you don't but I suspect you will) take a manifold vacuum reading with a good mechanical vacuum gauge, they are inexpensive and good tool to have.
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I have a vacuum gauge tool from when I had a Yamaha Maxim and an MG midget that needed the carbs synced. I’ll plug that in for you after I get the injectors back.
 
I don't think it's a compression issue, however, I would be interested in running that again with a newer gauge along with a leak down test just to establish a baseline.

I would also entertain replacing the plugs again because I have seen shitty plugs or even bad plugs right out of the box cause issues.

The one thing that caught my eye is fuel pressure. I know some of mercs manuals called out varying fuel pressures over the years, but 37 psi seems low. I think you should be around 43 psi +/-. When you disconnect the vacuum line from the regulator, does vacuum increase? If not, could point to a faulty regulator.
 
Also one other point worth mentioning, take any manual, but especially Seloc manuals with a grain of salt. They are known for mistakes. If something seems suspicious but is in spec, reverify it against another source.
 
Got word back from BAM Marine of Florida today they tested and cleaned all 8 injectors and found all eight are for sure in good working order and none showed any concerns beyond minor cleaning needed. Once they come back I'll update again as to whether or not this fixed the issue. If this doesn't fix it I am back to square one because I have no idea what could cause this issue then.
 
Hoplite808 said:
Got word back from BAM Marine of Florida today they tested and cleaned all 8 injectors and found all eight are for sure in good working order and none showed any concerns beyond minor cleaning needed. Once they come back I'll update again as to whether or not this fixed the issue. If this doesn't fix it I am back to square one because I have no idea what could cause this issue then.
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that's a bit shocking and I'm sure frustrating, but it's the only way to check that one off the list and move to other potential sources.
 
Fuel pump, fuel, fuel lines, gas tank, etc.
you’ve ruled out engine and electrical. Only other thing is fuel (related).
 
El Capitan said:
Fuel pump, fuel, fuel lines, gas tank, etc.
you’ve ruled out engine and electrical. Only other thing is fuel (related).
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Might be the next logical thing, but it's NEVER the only other thing. Read my saga. It was a spun crank bearing that stumped everyone on here, including me.
 
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