502 Overheating....Please Help
06-23-2007, 02:16 PM
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502 Overheating....Please Help
I have a problem and need some help.
I got a noise violation ticket with my 1999 Wellcraft Scarab 33’ AVS with twin 502 MPI’s. My engines are bone stock with no modifications. Against my better judgment I had installed a product inside the exhaust tubes that advertised a reduction of 10 dbi’s.
This is only where the problem begins.
It is my theory that inline mufflers or baffles caused the subsequent over heating problem. Although the marina says “No Way” I am ever more convinced that this is what started the initial over heating problem.
Since removing the baffles I have completed a leak down test, which although not perfect test good, replaced the exhaust manifolds, replaced impellor pump with complete assembly’s and replaced the thermostat.
The boat runs at idol for as long as you want without showing any signs of overheating, stays right about 150 degrees, consistent with no jumping of temp. When increasing the RPM’s the temp slowly increases about 2500 rpm’s rises to 180 degrees, pushing 3000 temp gets to a point where you need to shut the motor down at about 200 degrees. Let the set for a bit to cool, restart at idol temp goes back down to 150.
I am wondering if this is a possible head gasket, should I re-look at impellor pump, possible main engine water pump.
Any thoughts and ideas? Remember (my opinion only) this problem originally started because these baffles where installed creating the original overheating problem. At the same time is originally overheated the starter took a crap; I am not sure if it got hot and pushed a weak starter over the edge? Also when working on the impellers the marina noticed and replaced to “cracked” fuel injectors. So now, $2600 later, the boat still over heats.
Please help!!
I got a noise violation ticket with my 1999 Wellcraft Scarab 33’ AVS with twin 502 MPI’s. My engines are bone stock with no modifications. Against my better judgment I had installed a product inside the exhaust tubes that advertised a reduction of 10 dbi’s.
This is only where the problem begins.
It is my theory that inline mufflers or baffles caused the subsequent over heating problem. Although the marina says “No Way” I am ever more convinced that this is what started the initial over heating problem.
Since removing the baffles I have completed a leak down test, which although not perfect test good, replaced the exhaust manifolds, replaced impellor pump with complete assembly’s and replaced the thermostat.
The boat runs at idol for as long as you want without showing any signs of overheating, stays right about 150 degrees, consistent with no jumping of temp. When increasing the RPM’s the temp slowly increases about 2500 rpm’s rises to 180 degrees, pushing 3000 temp gets to a point where you need to shut the motor down at about 200 degrees. Let the set for a bit to cool, restart at idol temp goes back down to 150.
I am wondering if this is a possible head gasket, should I re-look at impellor pump, possible main engine water pump.
Any thoughts and ideas? Remember (my opinion only) this problem originally started because these baffles where installed creating the original overheating problem. At the same time is originally overheated the starter took a crap; I am not sure if it got hot and pushed a weak starter over the edge? Also when working on the impellers the marina noticed and replaced to “cracked” fuel injectors. So now, $2600 later, the boat still over heats.
Please help!!
06-23-2007, 02:50 PM
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Location: Where the water meets the oaks 'n Pines in the Sierra Nevada's of NorCal
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check out some of these posts for some ideas.
http://www.offshoreonly.com/forums/s...d.php?t=161231
good luck
http://www.offshoreonly.com/forums/s...d.php?t=161231
good luck
06-23-2007, 08:12 PM
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I can agree with your thinking of the inserts causing overheating. In theory, it can happen. Think along this route... If those inserts are causing enough of a restriction to eliminate sound they may be causing a restriction in water flow. If the water cant exit the pipes, not enough water will flow through the engine either.
