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Old 29-01-2010, 11:12   #136
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Ok, I am hauled out and I have taken the Max-Prop apart. The prop was set to a blade angle of 18 degrees which with a 20" diameter prop gives prop pitch in inches of 12.1

That SHOULD be a good pitch setting for this boat.... but in talking to the max prop guys they say that the addition of 2K pounds of weight plus an engine with 4,000 hours on it that is probably not giving the same power as when new could mean it needs to have the pitch lowered....

I do some testing when driving over to be hauled out. The smoke really starts to turn from light grey to medium grey at about 1500 rpm in gear. At 1800rpm the smoke is darker grey, at 2200rpm its a definite dark grey, at 2400rpm its black but not massive in quantity, at 2600rpm there is more black smoke and the exhaust water is getting sooty and at 2950rpm the max it will give the black smoke billows and the exhaust water is very sooty.

I tried powering in reverse... I did get more max rpm, perhaps 3200-3300 and the smoke seemed a bit less but it was hard to tell.

The Max propl tech guru says that a blade angle of 20 degree would be optimum according to the book for my boat. The blade angle I have now of 18 degree is a bit lower than he would expect. With the addition of weight and the age of the engine going to a blade angle of 16 degree which cooresponds to a pitch in inches of 10.8 is a bit aggressive but should be ok. He said any more than that is hiding some other problem.

I am going to set the max prop as they indicate to 10.8 inches of pitch but I really doubt this is my problem and I think there is still something wrong with the engine. No idea what that could be at this point.

I will post how she runs with the change in prop pitch. I fear that when the real problem is discovered (if ever) and corrected I will end up hauling again to repitch back up.


Terry
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Old 29-01-2010, 11:36   #137
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how would they know if 4000 hrs it alot.......did they do a compression test...or service the engine, I know everyone is just trying to help and those people you are dealing with really do have your best interestes in mind,........... but MAN, get the hell out of dodge and go somewhere else, this prop change should increase your revs by approx. 200rpm per pitch size
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Old 29-01-2010, 13:00   #138
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My experience...

When I put in my new John Deere 4045DFM50 (80 odd hp) I was only getting 1800 rpm. I had the 22" propeller repitched from 14" down to around 12" (from memory) and got 2250rpm (2500 max for engine) on a good day (everything clean).

With everything dirty my max rpm drops to 1800, with serious overload sounds from the engine if I try for any more. No smoke, though.

My prop is fixed pitch so I cannot reduce pitch any more so when the boat next comes out I'm going to have the diameter reduced (on prop shop recommendation) by an inch or so.

When I repowered I was advised to go from a 2" to a 4" exhaust and did so. It made no difference to the power though.

My John Deere technical adviser did suggest that instead of reducing the propeller diameter I could reset the maximum loaded rpm down to 2250!
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Old 29-01-2010, 14:35   #139
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Assuming that your transmission has a 2.62:1 ratio, my calculations indicate that a prop pitch of 10.8 is about right. A 12.1 pitch is over-propped. The prop pitch recommended by maxprop when we got our 3 bladed 18" diameter standard prop was one setting too high.

Chuck
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Old 29-01-2010, 14:53   #140
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Problem is not prop pitch.

The smoke and all symptoms are the same just at a higher rpm.
We get right at 3500rpm now but at that engine speed she pours clouds of black smoke and black sooty exhaust water. Boat speed showed 7.5 knots, about the same as before at 2,950rpm.

We also still get the smoke through the rev range.

I have no clue what is wrong but it's not prop.


Terry
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Old 29-01-2010, 14:56   #141
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Originally Posted by Tspringer View Post
Problem is not prop pitch.

The smoke and all symptoms are the same just at a higher rpm.
We get right at 3500rpm now but at that engine speed she pours clouds of black smoke and black sooty exhaust water. Boat speed showed 7.5 knots, about the same as before at 2,950rpm.

We also still get the smoke through the rev range.

I have no clue what is wrong but it's not prop.


Terry
the prop was a problem...it may have been overloading for quite some time if the setting match your 10y old notes.
lugging can cause excessive wear.

Is it tolerable at lower RPM?

go enjoy some R&R and deal with it when you get back.
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Old 29-01-2010, 15:16   #142
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Never monday.... thanks for your help, I do appreciate it very much.

At the old prop pitch settings I was able to achieve 3400rpm at least before and I never saw black smoke at any cruising speed. We never had any issues, until leaving the Marina 2 weeks ago when this mess started.

Even at cruising rpm and speed at this point we are still getting lots of black smoke and sooty exhaust water. Something is definitely wrong with the engine. I have a very hard time just ignoring such a thing and it seems that if in fact the engine itself is not the problem (compression is good) then running it with whatever is wrong with it still wrong would surely seem to shorten what life it has left.

IF I am going to have to face the horrid reality of a repower, why not bite the bullet now and commit financial suicide but at least get the benefits of a new engine rather than cancel the cruise (and go do what? Its not like I have a career left or anything) or wait to replace the engine later (it would certainly have to be replaced to sell the boat for anything approaching a decent price).

Basically, we are screwed. WE have an engine that cannot be correctly diagnosed and thus cannot be repaired. We already have $3,500 into attempts to repair it and nothing to show for that at all. Where does one draw the line? $5K? $10K? It seems to me that continueing to throw money at this is a waste. Perhaps the best approach to diesel engine repair is to simply skip straight to the last step and replace the engine at the first sign of a problem.

This really sucks.

The guys who have worked on it so far will NOT be working on it any more, I wouldnt let them back aboard on a bet. Marine Consulting Services based at Jacksonville Boat Yard..... parts changers extraordinaire but mechanics they are not.

Right now, the weather is not conducive to heading south. WE cannot go down the ditch due to mast height and a cold front is rolling in. It actually looks like it could be mid next week before we have a weather window for sailing south. I am going to watch it close... if there is any hint of a good passage past Cape Canaveral we will be out the inlet and on our way south. Perhaps a decent mechanic can be found south of here....

Anyone have a strong recommendation for a Yanmar specialist who can handle a repower in South Florida? Anyone wanna buy some new injectors and a new turbo for a 4JH2-HTE?


Terry
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Old 29-01-2010, 15:32   #143
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If you can get to Lauderdale. Look up Complete Yacht Services.
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Old 29-01-2010, 15:33   #144
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Terry,

I think Never Monday nailed it (he is the mechanic afterall). The problem was the prop. You have changed pitch enough that now the engine will get to a much higher rpm before it is overloaded! But, it is still overloaded. If you can get 4000rpm in neutral, but only 3400 in gear (before serious smoke), then you are still overpitched!! Forget what the prop recommendations for pitch were. You are still somewhat overpropped, but alot less than you were before.

What were you expecting for results??

What speed did you get at 3400?
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Old 29-01-2010, 15:37   #145
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Sorry, just noticed the boat speed of 7.5 knots. You engine will be much happier doing 7.5 knots at 3400 rpm than at 2900 rpm, especially if you get a headwind.

As to comparing what it used to do, you added 2000lbs!!! You will not get up to the same speed as before, at the same rpm. But, if you depitch a bit more, you will get to max rpms, wthout any smoke, and your engine will be happy. And then you enjoy cruising at about 80% of max rpms, even if it's a bit slower than before!!
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Old 29-01-2010, 15:40   #146
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I think you found the solution-

just GO! Sort of baby the engine- run it at just enough RPMs to keep your speed at 5.5- 6 knots. Forget 7.5 knots. If it was overpropped and cylinders glazed perhaps some running will help it.
But I agree, you should be able to get full 4000 RPM, any less and you are overpropped.

If you were going to repower anyway, who cares if the engine bites it? just go south and see what happens--- you'll know within a week if you really need to repower....

And maybe you can work something out with the next Yanmar mechanics- you give them a day to work on your current engine and if they can't fix it you'll repower through them- maybe they'll credit the diagnostics towards the repower.
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Old 29-01-2010, 15:41   #147
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Terry,

I think Never Monday nailed it (he is the mechanic afterall). The problem was the prop. You have changed pitch enough that now the engine will get to a much higher rpm before it is overloaded! But, it is still overloaded. If you can get 4000rpm in neutral, but only 3400 in gear (before serious smoke), then you are still overpitched!! Forget what the prop recommendations for pitch were. You are still somewhat overpropped, but alot less than you were before.

What were you expecting for results??

What speed did you get at 3400?
the pitch should be about good at 10-12" for a healthy engine

the fact he's overfueling and not making full load RPM leads me to a weak engine.
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Old 29-01-2010, 15:43   #148
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Terry,
can you post pictures?
I'd like a picture of your IP.
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Old 29-01-2010, 15:43   #149
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I could depitch the prop to zero.... then I will get all the rpm I could ever want and have the same no black smoke situation I get in neutral. Of course the boat will not move, but what the heck at least the smoke will be gone.

The max prop guru spent a long of time on the phone with me and was very helpful, he was also adamant that reducing the pitch beyond the point where I have it now would not be the right thing to do. Attempting to hide a problem with the engine simply by reducing the prop pitch far beyond where it should be is a solution, it is merely a strategy to try and hide whatever the issue is.

This boat... at this weight, with this engine and waterline length and transmission reduction ratio... the prop pitch we have now should be underpitched according to max prop. Spending another $500 for another haul out to reduce the pitch even more... that really does not sound like a sane us of limited funds.

When we get a weather window to sail south, we will go. In the meantime I am spending the wait time trying to figure out what is wrong and come up with a strategy for how we are going to fix it.

NM.... you want a photo of our IP? whats that?



Terry
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Old 29-01-2010, 15:49   #150
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What kind of boost are you getting at 3400 from the turbo?
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