| Author |
Message |
    
IAN MASON
Member
Username: riviera_27
Post Number: 12
Registered: 11-2007
| | Posted on Wednesday, March 12, 2008 - 01:17 am: | 
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Some advice please - Whilst on the water yesterday I pushed the boat up to 3200rpm to get on plane. All of a sudden the engine note changed and got louder, boat speed, rpm & temp didn't change. What could this be???? |
Larry Dumestre
Member
Username: salty_dog
Post Number: 4
Registered: 07-2007
| | Posted on Monday, March 17, 2008 - 06:09 pm: |
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Check your smoke limiters. Solenoid could be opening while underway. |
IAN MASON
Member
Username: riviera_27
Post Number: 15
Registered: 11-2007
| | Posted on Monday, March 17, 2008 - 10:19 pm: |
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Thanks for the reply Larry.
Excuse my ignorance but, what is a 'Smoke Limiter' and how do I check them? |
Morten Ringvold
Senior Member
Username: haffiman37
Post Number: 2474
Registered: 04-2006
| | Posted on Monday, March 17, 2008 - 10:47 pm: |
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Smoke limiter is normally a membrane on top of the injection pump, connected to the intake manifold. This will limit the pump injection amount according to turbo pressure.
Larry seems to refer to the 'exhaust brake' that was installed partly blocking the exhaust at idle to put some load on the engine to make it reach operating temperature. However with throttle above idle, this should be open anyway.
Was the change in sound from engine itself, or from the exhaust.
If from the exhaust and if You have one of the original Volvo silencers with steel ends and big rubber hose between, the reason might be that one of the internal baffel plates has come loose. |
IAN MASON
Member
Username: riviera_27
Post Number: 16
Registered: 11-2007
| | Posted on Tuesday, March 18, 2008 - 07:05 pm: |
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Thanks Morten for the explanation. The change in note was from the exhaust and as I am not sure which exhaust is fitted I have sent a picture to your e-mail (hope thats Ok)to see if you can help identify it. I was told that this note change could merely be the exhast in the leg breaking the surface of the water as the boat comes on to plane. Does this sound possible? |
Morten Ringvold
Senior Member
Username: haffiman37
Post Number: 2476
Registered: 04-2006
| | Posted on Tuesday, March 18, 2008 - 08:01 pm: |
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First of all, Your engine is not a TAMD 41, but an AqAD 41. TAMD is the inboard version with straight shaft, Aq is the drive version.
As Aq does not have an exhaust muffler, my possible reason is not valid, but Yours is more likely. Check that the rubber flap has not fallen off the exhaust outlet on the drive. |
IAN MASON
Member
Username: riviera_27
Post Number: 17
Registered: 11-2007
| | Posted on Monday, March 24, 2008 - 08:54 pm: |
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Whoops, if nothing else i've learned what model engine I have (sorry about that). I checked at the weekend and the rubber flaps are in place. We ran the boat and it is deffinately louder, more of a reverbarating noise. No loss of power and temp is normal. Do the exhaust manifolds ever give problems on these models? I am happy to live with it but it concerns me that something may be starting to fail. |
Morten Ringvold
Senior Member
Username: haffiman37
Post Number: 2502
Registered: 04-2006
| | Posted on Monday, March 24, 2008 - 09:38 pm: |
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Here are some other things that may have an impact of your 'problem'.
weight and balance of the boat.( Full or empty fuel/water tanks).
Boat speed.
Trim angle of drive.
Fouled/clean bottom.
Has You exhaust bellow got loose or cracked? |
IAN MASON
Member
Username: riviera_27
Post Number: 20
Registered: 11-2007
| | Posted on Tuesday, March 25, 2008 - 07:40 pm: |
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Water tank full, fuel tank 2/3 full and clean hull. Good point on the exhaust bellow though, will check it out and let you know. Do the exhaust manifolds on these engines ever give problems? |
Morten Ringvold
Senior Member
Username: haffiman37
Post Number: 2509
Registered: 04-2006
| | Posted on Tuesday, March 25, 2008 - 08:19 pm: |
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Exhaust manifold is fresh water cooled, but the mixer (end part) normally has a 10 years life time at least. |
IAN MASON
Member
Username: riviera_27
Post Number: 21
Registered: 11-2007
| | Posted on Tuesday, April 08, 2008 - 03:10 am: |
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Yes, you were right, exhaust bellow has come loose at sterndrive. I think I'm right in thinking that this should be Ok to run until I next slip the boat? Thanks again for your great advice. |
Morten Ringvold
Senior Member
Username: haffiman37
Post Number: 2596
Registered: 04-2006
| | Posted on Tuesday, April 08, 2008 - 03:25 am: |
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The good thing: We probably found the reason.
Would not have waited too long to have it corrected, but be sure You have a new bellow at hand when You slip. |
