You might had enough heel angle at 40 degrees to have the oil pick up out in the air and no oil pressure for a short time. When the boat got back on her feet you got pressure back. If you were a little low on oil this can happen. We don't usually run our engines at 40 degrees.
Question for all gearheads
- Thread starter sailaway78
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I've experienced similar on our C30, turns out the cutlless bearing was worn enough to permit the shaft to vibrate under the right conditions. This situation got progressively worse ( only during heavy weather or extreme tidal flow when the prop had great pressure on it) until the cutless bearing was changed, peace since then.
Not an oil pressure issue
OK To dispell the low oil pressure issue. First, the engine is not even half a quart low on oil. Second, one of the very first things I looked at was oil pressure. The guage was showing over 50psi, and never wavered.
The heel or 30 to 40 degrees was not a constant. When ever a major gust hit, the boat would roll way over, but only for a matter of seconds. The worse part was the following seas. And there is no way anyone can make me believe that any hammering that loud for 30 seconds or so, even one time, let alone three times, would not cause permanent damage, and would never just go away. I have heard rods knock before, and have broken more than one rod, and a few crankshafts, back in my race days. That much internal engine noise, does not cure itself, ever.
OK To dispell the low oil pressure issue. First, the engine is not even half a quart low on oil. Second, one of the very first things I looked at was oil pressure. The guage was showing over 50psi, and never wavered.
The heel or 30 to 40 degrees was not a constant. When ever a major gust hit, the boat would roll way over, but only for a matter of seconds. The worse part was the following seas. And there is no way anyone can make me believe that any hammering that loud for 30 seconds or so, even one time, let alone three times, would not cause permanent damage, and would never just go away. I have heard rods knock before, and have broken more than one rod, and a few crankshafts, back in my race days. That much internal engine noise, does not cure itself, ever.
Just a random thought, but with the pitching and rolling, could your starter pall have been impinging on the flywheel? That would be close approximation of an AK-47..."our adversary's weapon of choice. It makes a distinctive sound when fired." Has your starter been replaced..checked for security?
HMMM A novel idea
Nope, had not even considered something like the starter pawl. Never entered my though process. Starter was replaced two years ago, and has not been looked at since. I will check that, but this just didn't seem to be coming from the engine bay. Sounded much more like it was under the boat.
Nope, had not even considered something like the starter pawl. Never entered my though process. Starter was replaced two years ago, and has not been looked at since. I will check that, but this just didn't seem to be coming from the engine bay. Sounded much more like it was under the boat.
At any time did you take it out of gear while it was making the banging sound ?? This will at least isolate the drive train from the possible exhaust/engine noise. Maybe if it happens again try it and see what happens (if circumstance and condtions alow). With out more detailed info I am going with the shaft but not sure why it was intermitten except that sea conditions may have caused some flexing ?? If you really think it was an exhaust sound you could always try to duplicate it by taking the belt off sea water pump and run engine for 15 seconds to see if it replicates the sound but unlikely. Was the boat heeled over far enought to expose the raw water thru hull causing the pump to lose prime ?? 40 degrees heel is pretty extreme. Was the exhaust underwater when you were going thru the channel when it first occurred ?? Do you think it could possible be a shaft zinc loose slipping on shaft either hitting the hull or strut and even then it would be hard to explain why it was intermitten. sounds like it is time to dive and do a hull/ shaft/strut /prop inspection. If all other ideas don't pan out you can alway call "Click and Clack the Tappet Brothers" on NPR radio and maybe your problem the could be the "PUZZLER" ...............Good Luck ! and I for one am really curious to know what the problem was keep us updated !
I get the exact sound with my Oday and and I can make go away by lowing the throttle or increasing it and I have changed the cutlass bearing and checked it all so I'm thinking it's banging against the shaft log and it only does it once in a blue moon and it's possible current has something to do with it
Good question
And my theory. I once had an impeller spin the hub, and quit pumping water. There was a noticable difference in exhaust noise, and an almost immediate increase in engine temp. The exhaust was somewhat louder, not a lot. Mosty different. But, even if the cooling water intake is somehow stopped, there is still water in the muffler itself. I think that some way, the wave action from the following seas, and the rolling motion, caused the exhaust pressure to somehow burp ALL the water out of the muffler. Much as you would clear a snorkel when you get water in it. And I was heeled over to port, and the intake is on the port side, and there was no increase in temp.
And my theory. I once had an impeller spin the hub, and quit pumping water. There was a noticable difference in exhaust noise, and an almost immediate increase in engine temp. The exhaust was somewhat louder, not a lot. Mosty different. But, even if the cooling water intake is somehow stopped, there is still water in the muffler itself. I think that some way, the wave action from the following seas, and the rolling motion, caused the exhaust pressure to somehow burp ALL the water out of the muffler. Much as you would clear a snorkel when you get water in it. And I was heeled over to port, and the intake is on the port side, and there was no increase in temp.
Will look at that
I'll have to take a look at that. Not sure how to tell. Checked the shaft for any bend or any visible signs of anything abnormal. I do have a PSS seal.
I'll have to take a look at that. Not sure how to tell. Checked the shaft for any bend or any visible signs of anything abnormal. I do have a PSS seal.
Since you have looked at the obvious causes, those can be dismissed.
You described the sound of "injector rap". Air or a small particle made it to the injector and took time to get through. I've had it happen in a truck and you would swear the whole engine was coming apart; but then it goes away. Under the conditions you described, with the engine and fuel system bouncing around it could have caused it.
You described the sound of "injector rap". Air or a small particle made it to the injector and took time to get through. I've had it happen in a truck and you would swear the whole engine was coming apart; but then it goes away. Under the conditions you described, with the engine and fuel system bouncing around it could have caused it.
An Engineers View of your Biloxi Blues.
There are several reasons that I can think of causing a boat to make a sound like the one you have recounted but to have it reoccur 2 more times the same way narrows down the field a bit. You narrowed down the field even more by discounting other ideas. This only leaves 1 answer which..... no one seems to have come up with yet. The Engine.
I have a Hunter 40 with the 44hp Yanmar engine. It occasionally makes the sound you have explained while I am motoring. Never to the extent you have reported but I can see how it could happen.
Here's the problem. Your diesel engine was either Knocking........ or backfiring . These are two different problems with a similar sound. I can't tell you exactly which one yours is doing, but I will give you some reasons why either happens and you will have to check to see if the problem exists in your engine . It may be any one of these or a combination of them.
First you must understand what the word Octane means.
http://en.wikipedia.org/wiki/Octane_rating
(VW Passat diesel engines have had a similar issue but lasting much longer. I almost bought one but backed away when I restarted the engine after the test drive and it started rapping.)
http://www.fixya.com/tags/knocking_sound_engine/browse/volkswagen
Here are some possible answers:
1) The red marine fuel makes my engine knock or backfire..... don't know which, but it sounds like a gun going off under water and hitting the boat making a kind of muffled pinging sound. I guess the red fuel has either a little lower or higher octane rating. This makes the fuel harder to burn so it fires early or late. If I were to put regular road diesel in the tank I think it would stop......... Yah ahhhhhh....... it might fix the problem....... to bad I can't try it because that would not be legal. Do you use Marine Diesel ???
2) When your boat got all stirred up in the weather, so did your fuel tank. The crap in your tank, (diesel bacteria, water or unmixed diesel additives) will float up and get sucked into the engine, raising the octane level and causing backfiring .
3) While your boat was on it's side and with the fuel line or filter clogged the engine temporarily burned its own oil.......which I assure you can happen. Engine oil has a much higher octane level so it might cause backfiring.
4) Did you accidentally put a little gas in your diesel tank ?? They do mix but some gas may go to the top. This will cause the engine to pre-ignite or knock. Eventually it could self destruct.
5) The main heart of your diesel engine is the injector pump. in a modern 4 cycle diesel engine the pump must be timed to squirt the fuel in at the exact time. To early or to late will cause the banging. If dirt gets into the pump it will slow down causing the banging. I'm not sure but I think there is a sort of advance on the pump, like the vacuum advance on a cars distributor. It's purpose would be to pre-pump the the fuel when the engine is running at high speeds. If this didn't happen, you could get the banging.
It's only a theory..... I broke my leg in HS so I missed this portion of auto-shop.
6) Lastly.....135 degrees is to cold for a Diesel engine to run. If the glow plugs are to cold or to hot this would cause the engine to fire early or late.
I believe one of these two, early or late ignition are causing your problem. If I am correct, and the symptoms continue, left unattended, this will take your engine out. Treat this as a serious problem, you need the engine to work under extreme situations. Find a very good mechanic to truly diagnose the problem.
Of course this is only a theory...........
Good luck,
Tom
There are several reasons that I can think of causing a boat to make a sound like the one you have recounted but to have it reoccur 2 more times the same way narrows down the field a bit. You narrowed down the field even more by discounting other ideas. This only leaves 1 answer which..... no one seems to have come up with yet. The Engine.
I have a Hunter 40 with the 44hp Yanmar engine. It occasionally makes the sound you have explained while I am motoring. Never to the extent you have reported but I can see how it could happen.
Here's the problem. Your diesel engine was either Knocking........ or backfiring . These are two different problems with a similar sound. I can't tell you exactly which one yours is doing, but I will give you some reasons why either happens and you will have to check to see if the problem exists in your engine . It may be any one of these or a combination of them.
First you must understand what the word Octane means.
http://en.wikipedia.org/wiki/Octane_rating
(VW Passat diesel engines have had a similar issue but lasting much longer. I almost bought one but backed away when I restarted the engine after the test drive and it started rapping.)
http://www.fixya.com/tags/knocking_sound_engine/browse/volkswagen
Here are some possible answers:
1) The red marine fuel makes my engine knock or backfire..... don't know which, but it sounds like a gun going off under water and hitting the boat making a kind of muffled pinging sound. I guess the red fuel has either a little lower or higher octane rating. This makes the fuel harder to burn so it fires early or late. If I were to put regular road diesel in the tank I think it would stop......... Yah ahhhhhh....... it might fix the problem....... to bad I can't try it because that would not be legal. Do you use Marine Diesel ???
2) When your boat got all stirred up in the weather, so did your fuel tank. The crap in your tank, (diesel bacteria, water or unmixed diesel additives) will float up and get sucked into the engine, raising the octane level and causing backfiring .
3) While your boat was on it's side and with the fuel line or filter clogged the engine temporarily burned its own oil.......which I assure you can happen. Engine oil has a much higher octane level so it might cause backfiring.
4) Did you accidentally put a little gas in your diesel tank ?? They do mix but some gas may go to the top. This will cause the engine to pre-ignite or knock. Eventually it could self destruct.
5) The main heart of your diesel engine is the injector pump. in a modern 4 cycle diesel engine the pump must be timed to squirt the fuel in at the exact time. To early or to late will cause the banging. If dirt gets into the pump it will slow down causing the banging. I'm not sure but I think there is a sort of advance on the pump, like the vacuum advance on a cars distributor. It's purpose would be to pre-pump the the fuel when the engine is running at high speeds. If this didn't happen, you could get the banging.
It's only a theory..... I broke my leg in HS so I missed this portion of auto-shop.
6) Lastly.....135 degrees is to cold for a Diesel engine to run. If the glow plugs are to cold or to hot this would cause the engine to fire early or late.
I believe one of these two, early or late ignition are causing your problem. If I am correct, and the symptoms continue, left unattended, this will take your engine out. Treat this as a serious problem, you need the engine to work under extreme situations. Find a very good mechanic to truly diagnose the problem.
Of course this is only a theory...........
Good luck,
Tom
I have a similar noise we have been trying to figure out and I'm thinking Donaldlex is on the correct track.
Only the noise is always there unless at a lower RPM and it never happens out of gear.
Also, when in larger waves and when we were riding up and down them the noise would subside for a second.
A friend was along on a trip we just returned from and stood in the engine compartment over the shaft. In our case we need to figure this out because it happens every time we motor.
I will be posting a question on Shaft packing shortly.
When we bought the boat in January it was hauled and the cutlass bearing had no play that i could feel.
We think the shaft is out of alignment or possible aligned but out of center.
THE exhuast system is something we didn't think of.
We seem to have a consistent flow of water at all RPM's so I don't think it's a dry system thats making the noise, but I will look into that as a possibility .
If / When you find the source please post, I'll be looking forward to figuring this out for our boat. I would guess it was a temporary thing for you and you may not hear it again.
Brian
Only the noise is always there unless at a lower RPM and it never happens out of gear.
Also, when in larger waves and when we were riding up and down them the noise would subside for a second.
A friend was along on a trip we just returned from and stood in the engine compartment over the shaft. In our case we need to figure this out because it happens every time we motor.
I will be posting a question on Shaft packing shortly.
When we bought the boat in January it was hauled and the cutlass bearing had no play that i could feel.
We think the shaft is out of alignment or possible aligned but out of center.
THE exhuast system is something we didn't think of.
We seem to have a consistent flow of water at all RPM's so I don't think it's a dry system thats making the noise, but I will look into that as a possibility .
If / When you find the source please post, I'll be looking forward to figuring this out for our boat. I would guess it was a temporary thing for you and you may not hear it again.
Brian
There are several reasons that I can think of causing a boat to make a sound like the one you have recounted but to have it reoccur 2 more times the same way narrows down the field a bit. You narrowed down the field even more by discounting other ideas. This only leaves 1 answer which..... no one seems to have come up with yet. The Engine.
I have a Hunter 40 with the 44hp Yanmar engine. It occasionally makes the sound you have explained while I am motoring. Never to the extent you have reported but I can see how it could happen.
Here's the problem. Your diesel engine was either Knocking........ or backfiring . These are two different problems with a similar sound. I can't tell you exactly which one yours is doing, but I will give you some reasons why either happens and you will have to check to see if the problem exists in your engine . It may be any one of these or a combination of them.
First you must understand what the word Octane means.
http://en.wikipedia.org/wiki/Octane_rating
(VW Passat diesel engines have had a similar issue but lasting much longer. I almost bought one but backed away when I restarted the engine after the test drive and it started rapping.)
http://www.fixya.com/tags/knocking_sound_engine/browse/volkswagen
Here are some possible answers:
1) The red marine fuel makes my engine knock or backfire..... don't know which, but it sounds like a gun going off under water and hitting the boat making a kind of muffled pinging sound. I guess the red fuel has either a little lower or higher octane rating. This makes the fuel harder to burn so it fires early or late. If I were to put regular road diesel in the tank I think it would stop......... Yah ahhhhhh....... it might fix the problem....... to bad I can't try it because that would not be legal. Do you use Marine Diesel ???
2) When your boat got all stirred up in the weather, so did your fuel tank. The crap in your tank, (diesel bacteria, water or unmixed diesel additives) will float up and get sucked into the engine, raising the octane level and causing backfiring .
3) While your boat was on it's side and with the fuel line or filter clogged the engine temporarily burned its own oil.......which I assure you can happen. Engine oil has a much higher octane level so it might cause backfiring.
4) Did you accidentally put a little gas in your diesel tank ?? They do mix but some gas may go to the top. This will cause the engine to pre-ignite or knock. Eventually it could self destruct.
5) The main heart of your diesel engine is the injector pump. in a modern 4 cycle diesel engine the pump must be timed to squirt the fuel in at the exact time. To early or to late will cause the banging. If dirt gets into the pump it will slow down causing the banging. I'm not sure but I think there is a sort of advance on the pump, like the vacuum advance on a cars distributor. It's purpose would be to pre-pump the the fuel when the engine is running at high speeds. If this didn't happen, you could get the banging.
It's only a theory..... I broke my leg in HS so I missed this portion of auto-shop.
6) Lastly.....135 degrees is to cold for a Diesel engine to run. If the glow plugs are to cold or to hot this would cause the engine to fire early or late.
I believe one of these two, early or late ignition are causing your problem. If I am correct, and the symptoms continue, left unattended, this will take your engine out. Treat this as a serious problem, you need the engine to work under extreme situations. Find a very good mechanic to truly diagnose the problem.
Of course this is only a theory...........
Good luck,
Tom
I have a Hunter 40 with the 44hp Yanmar engine. It occasionally makes the sound you have explained while I am motoring. Never to the extent you have reported but I can see how it could happen.
Here's the problem. Your diesel engine was either Knocking........ or backfiring . These are two different problems with a similar sound. I can't tell you exactly which one yours is doing, but I will give you some reasons why either happens and you will have to check to see if the problem exists in your engine . It may be any one of these or a combination of them.
First you must understand what the word Octane means.
http://en.wikipedia.org/wiki/Octane_rating
(VW Passat diesel engines have had a similar issue but lasting much longer. I almost bought one but backed away when I restarted the engine after the test drive and it started rapping.)
http://www.fixya.com/tags/knocking_sound_engine/browse/volkswagen
Here are some possible answers:
1) The red marine fuel makes my engine knock or backfire..... don't know which, but it sounds like a gun going off under water and hitting the boat making a kind of muffled pinging sound. I guess the red fuel has either a little lower or higher octane rating. This makes the fuel harder to burn so it fires early or late. If I were to put regular road diesel in the tank I think it would stop......... Yah ahhhhhh....... it might fix the problem....... to bad I can't try it because that would not be legal. Do you use Marine Diesel ???
2) When your boat got all stirred up in the weather, so did your fuel tank. The crap in your tank, (diesel bacteria, water or unmixed diesel additives) will float up and get sucked into the engine, raising the octane level and causing backfiring .
3) While your boat was on it's side and with the fuel line or filter clogged the engine temporarily burned its own oil.......which I assure you can happen. Engine oil has a much higher octane level so it might cause backfiring.
4) Did you accidentally put a little gas in your diesel tank ?? They do mix but some gas may go to the top. This will cause the engine to pre-ignite or knock. Eventually it could self destruct.
5) The main heart of your diesel engine is the injector pump. in a modern 4 cycle diesel engine the pump must be timed to squirt the fuel in at the exact time. To early or to late will cause the banging. If dirt gets into the pump it will slow down causing the banging. I'm not sure but I think there is a sort of advance on the pump, like the vacuum advance on a cars distributor. It's purpose would be to pre-pump the the fuel when the engine is running at high speeds. If this didn't happen, you could get the banging.
It's only a theory..... I broke my leg in HS so I missed this portion of auto-shop.
6) Lastly.....135 degrees is to cold for a Diesel engine to run. If the glow plugs are to cold or to hot this would cause the engine to fire early or late.
I believe one of these two, early or late ignition are causing your problem. If I am correct, and the symptoms continue, left unattended, this will take your engine out. Treat this as a serious problem, you need the engine to work under extreme situations. Find a very good mechanic to truly diagnose the problem.
Of course this is only a theory...........
Good luck,
Tom
Oirion 253,
I might be misunderstanding your post .....
It is NOT illegal to buy Road fuel to use in off road engines, ie.Boat diesel, because you pay tax at the pump for road fuel. It IS illegal to buy OFF ROAD non taxed fuel to use in on road engines.....
I might be misunderstanding your post .....
It is NOT illegal to buy Road fuel to use in off road engines, ie.Boat diesel, because you pay tax at the pump for road fuel. It IS illegal to buy OFF ROAD non taxed fuel to use in on road engines.....
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