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So I’m new to the group… I love my 290 Amberjack but its time to move up because the Admiral wants more space and I want Diesels! Hopefully I can get some advice here. I’m a hobbyist mechanic, but my expertise ends past the dipstick and the wiring harness. We are looking at a 390DA with 700h QSB 380’s and in one of the pictures the stbd turbo looks like it has gotten hot enough to fry all the paint, the port motor does not have the same look. My questions- is it normal? what could have done that if not? is it a walk away issue? I really appreciate anyone’s advice. Obviously I’ll get a complete motor survey before buying but I’m looking for a bit of insight before spending that $
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Vessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
Sean, you’ve got some real good feedback above so hopefully it’s clear enough as to the issues at hand here. I do have a strong hull surveyor recommendation for the CT area if ever needed. Let me know.
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Chocolate Pudding
Sean,
The reason behind the recommendations to walk away is that too much fuel has been burned by the engines. This is the result of Sea Ray installing propellers that are pleasing to the owners’ idea of performance but at the same time those propellers ask way too much of the engines thus requiring too much fuel to be burned. When we say too much fuel, that is when compared to the Cummins recommended MAXIMUM at any cruise RPM. So….. The result is excess heat in all the wrong places. The first visual indication is the darkening of the Turbos and Aftercoolers. As the engines burn fuel they expel heat out the exhaust. As the heat travels over the valves and seats they heat too much and will eventually give in. When they do, it is game over for the engine! There is no normal survey that can tell you when this will happen or any other complication from the OverPropped condition. The engine would need to be taken apart to gain access to the affected parts and even then you probably would not get an accurate assessment.
What the discoloration tells you is that the previous owners did not know how to operate the boat/engines properly. This is referred to as the “Nut Behind the Wheel” You do not want to inherit the issues that WILL come from this.
I have the 40Sundancer with Gas engines. I love the boat but could not find a suitable Diesel equipped 40DA in my market and in a time frame that suited me and my Admiral. So we bought this one and continue to look for a boat with diesels that will meet our cruising needs AND has been setup, treated and operated well. That is a very tall order……….. The Beneteau Swift 47 looks like a viable option but we will need to wait until they show up on the brokerage market.
Take the time to read the wealth of information on this site about Propeller overloading on the different engines. B,C and M. There are different complications but they all stem from the same root cause. Too much propeller asking the engines to burn too much fuel at any RPM on plane. When you are off plane and running at hull speed the load is small. When you ask the engines to spin the props so that the boat will plane, the fuel burn goes way up. It is the fuel burn on plane and at cruise that will do the damage if the correct setup is not configured.
I burn 7.5 gph when cruising at 9.5mph @1700rpm. When I ask my engines to spin at 3500RPM and get the boat going at 22mph those big blocks burn 40gph. That is 4x the fuel burn but only 2x the speed. See the problem?
I would also pass on the boat you are considering. I casually look at pictures and compare the discoloration to a simple scale. Vanilla, Butterscotch and Chocolate pudding. Anything in the Butterscotch to Chocolate range gets an immediate pass because of all of the hidden complications.
Hope this helps
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Donāt get blinders because you like a boat. Unless the seller gives you a credit for two new engines installed then walk away.. way to much liability and no way to know exactly when the ticking time bomb will go boom… but it will…..
No information the buyers mechanic can provide will change that.
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Vessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
Not QSM …. QSB 5.9 380’s. Not at all a great photo but I think it shows enough that probably best to just move on to the next one. Looks like they run overloaded (which is a known issue with that boat/engine package per factory setup) and that one engine had a bad incident involving a coolant loss / overheat …
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