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  1. #1

    Default Temp alarm and risers overheating

    Our Volvo penta 4.3 gl keeps giving us an audible warning with the temp gauge reaching 250 within 5 minutes on the water. We have had the boat in the shop twice spending over $800 and the issue still persists. We read the engine block and risers with an IR gun when the alarm starts sounding. All temps are within normal range with the risers typically at 120 and engine at about 195. So we unhook the temp sensor and continuing to cruise for a while checking temps periodically. Typically after about an hour or so of running the boat the exhaust risers will overheat to about 180+ and you can hear bubbling. The impeller has been changed, exhaust risers and manifolds inspected for blockage and corrosion and nothing. This last time in the shop, a cracked grommet was found in the water tube. Took the boat back out and acts the exact same. Audible warning going off soon after getting in the water although everything reads normal. At this point, I'm tired of spending money on boat mechanics who can't fix the issue. Does anyone have any possible insight? Is this two separate issues with the audible warning and then something else causing the risers to overheat or could they be related even tho our IR gun doesn't show any overheating when the warning starts going off. Oh and now the boat doesn't want to start immediately and ending up dying on us while cruising back to shore. We did get it started back up tho and got it pulled in.

  2. #2
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,189

    Default Re: Temp alarm and risers overheating

    OK..... first, we need more info re; your engine model number.
    Launch this web site and identify your engine.
    http://www.marinepartseurope.com/en/...neEngines.aspx


    My first suggestion would be to argue that the related work as per the $800 charge was futile. You may want to ask that they refund all or a portion of it....... or, that they continue diagnosing and correcting the problem on their dime!
    The longer that this issue goes un-attended, the greater the risk of Engine Damage!


    My second suggestion would be for future service work.
    a..... Be willing to pay for diagnostics up front.
    b..... Hold their feet to the fire and expect that the Diagnostics will actually identify the problem.
    c..... Authorize the work scope only upon a written understanding that the diagnostics are correct, and that the work scope will indeed correct the problem!

    Otherwise, you may as well sign over a blank check!




    While we do not have a model number....... I don't believe that your Volvo Penta 4.3L engine will be fitted with Risers/Spacers.
    You should have Elbows that will host the over-temp sensors.

    If Raw Water Cooled, you will have seawater transfer ports between the exhaust Manifolds and Elbows.


    When this boat was new, all works as it should. So we know that the system can be made to work correctly and without any issues.

    So..... something has changed as to create the now over-heating.

    ...... check and/or replace the seawater pump impeller....... or if need be, replace the entire seawater pump.
    ...... pull a vacuum test on the seawater pump's suction hose and look for a suction breach. One small breach will play hell on the system!
    ...... check all related hoses for interior de-lamination.
    ...... look for any excessively tight bends in the seawater path hoses.
    ...... check for rust scale blockage within the seawater passages.
    ...... ** check the seawater transfer ports between the Manifolds and Elbows.
    ...... ** if the engine is an early model, and is fitted with the 95mm exhaust Elbow, make darn sure that the 95mm soft wall exhaust hose is NOT being compressed into the elbow scalloped areas.
    ..... check the exhaust outlet port "back-flow-prevention flappers" for any signs of resistance.
    ..... in other words, check the entire seawater path from the point of entry to the point of discharge!

    (** these are important ones!)



    The first image below is of a typical Volvo Penta exhaust manifold and elbow showing the seawater transfer ports.
    (this is the earlier AQ series)
    The seawater transfer ports must be clean and clear or rust scale.

    On the AQ series exhaust system, you will see the exhaust elbow scalloped areas that I mentioned.
    The OEM 95mm exhaust couplers are always too short by approx 2" of length!
    Because these are too short, they inadvertently become adjusted and clamped over the scalloped areas.
    Over time, they eventually become squeezes into the scallops and restrict "spent" seawater flow!
    The result is over-heating!
    DO NOT..... repeat..... DO NOT clamp this 95mm coupler over the scalloped areas.
    If your 95mm soft wall exhaust couplers are short, purchase new 95mm soft wall exhaust hose by the foot and move the band clamps further up the elbow snout and away from the scalloped area.

    But again, we need to know your engine model number.
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    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  3. #3

    Default Re: Temp alarm and risers overheating

    It appears to be a 4.3 GL-B The manual says it's for several different engines but the only 4.3 GL listed is the 4.3 GL-B. Is there a way to know for sure? I will try and post a couple pics.

  4. #4

    Default Re: Temp alarm and risers overheating

    I have attached the pictures showing the engine along with the exhaust manifold and elbow area. It doesnt appear to be the same type as the picture shown so I dont know if there is a scalloped area or not on this one.
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  5. #5
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,189

    Default Re: Temp alarm and risers overheating

    OK..... you have a later model stern drive package with the SX style drive, of which is a Gimbal Suspension system..... not an AQ series!

    Your exhaust elbows will NOT have the scallops, nor will the soft wall hose be 95mm......... but you will have similar "seawater transfer ports" that MUST be clear, clean and free-flowing.


    .
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  6. #6

    Default Re: Temp alarm and risers overheating

    We checked one side and the seawater transfer ports for rust and corrosion or a blockage and all was clear in the manifold and riser. That was the side that gets hotter too. The biggest problem is that when we take it for service they can't duplicate the overheating in the shop. But I took a video this last time of the temps on the IR gun and called the marine shop that did the work last time. They told us to bring it back in free of charge so that's good news. We don't feel comfortable taking apart and inspecting the entire system ourselves so hopefully this time they will do a complete inspection and find the problem. I'm just praying there isn't any engine damage at this point.

  7. #7
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,189

    Default Re: Temp alarm and risers overheating

    .........................
    Quote Originally Posted by Stackkl View Post
    We checked one side and the seawater transfer ports for rust and corrosion or a blockage and all was clear in the manifold and riser. That was the side that gets hotter too.
    FYI..... your system does not incorporate "Risers/Spacers". Even though you will see the term "riser" being used, you have Manifolds and Elbows only.
    That said...... I would remove both sides and examine.


    The biggest problem is that when we take it for service they can't duplicate the overheating in the shop. But I took a video this last time of the temps on the IR gun and called the marine shop that did the work last time. They told us to bring it back in free of charge so that's good news. We don't feel comfortable taking apart and inspecting the entire system ourselves so hopefully this time they will do a complete inspection and find the problem.

    Yes..... ask them to start at the point of seawater entry and work forward.


    I'm just praying there isn't any engine damage at this point.
    Yes.
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

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