Mercury 496 Mag trouble, need help
06-19-2020 | 01:47 PM
#21
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Per Mercruiser support (I gave them the engines' serial number) they said the block numbers were the same for each engine which as I previously posted are 101XYT1. For those block numbers the CAM Sensor is 883513. But they also said 881666 would work though the block numbers I got for that are 2XY and 2XF and 3XY
06-21-2020 | 07:01 PM
#23
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Any help please. i have a 2008 boat with twin mercruiser 496 smartcraft engines. I have concerns about age of my manifolds I believe they are the dry manifold system with stainless risers. The boat has only about 180 hours on it.The manifolds are about 12 years old now. Boat is used in salt water but always flushed out with salt away. I had a marine mechanic pull one of the manifolds and riser off to the change a bad starter. The manifolds appear to look good inside. How long do these manifolds last? I'm looking for someone who really knows what they're talking about. I have read peoples opinions on replacing after 5 yrs but looking for a experienced mercruiser mechanics answer. Boat runs fine temperatures 170 ish. What happens when manifolds go bad? How do you inspect? Can water get in engine with the dry system if they go bad or do they just start increasing engine exhaust temperatures as they rust and clog up?
06-19-2021 | 04:40 PM
#25
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From: KY
09-02-2023 | 03:00 PM
#26
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More info as I have to think about how to write all of this as it is very important info about the early 496's from Mercruiser.
first of all your fault beeps IMO are from your CAM sensor as the PCM 555 is not receiving the correct cam PS signal / reluctor wheel on the gear / the new cam sensor you installed is not reading nor sending the proper input signal to the PCM hence the output signals from the PCM is throwing a fault code / warning beeps along with the engine runs like crap. just saying.
Next the tech BS of this and what is going on. Hope my words make sense of all this.
the cam PS and the crank PS supply the PCM with timing and RPM information as inputs to the PCM 555. When a failure takes place in both and one of these circuits, the engine will run rough and backfire and can even shut down. First and foremost check for continuity between the sensor(s) and the PCM first of all to make sure that is OK plus the connectors / connections are in very good shape with no rust or moisture on them.
It is best to test the sensors as well for resistance values. Most marine OEM's require testing them (sensors) at around 70 degrees for proper resistance values FYI so room temp would be good to.
Values are
camshaft PS - A to B 24.04 mohms then B to C 24.05 mohms
crankshaft PS - A to B 23.2 mohms then B to C 23.21 mohms
I have posted this info before up here.
here is the kicker with Merc and important info for many who even scan the engine and get nothing.
all PCM 555 software prior to level 091, a malfunction with the crankshaft PS and or the Camshaft PS will NOT set a FAULT. With level 091 (PCM 555) if the CAMSHAFT PS is bad or faultly in any shape or form however and does not send the a signal and or the proper signal to the PCM - the engine will backfire and at times will not start in some cases.
Here is what can take place as stop cranking the engine over and then try to restart the engine - operating the engine for 20 seconds to set faults. the (fault) warning alarm will be set 2 beeps per minute. With that said IMO your 2 beeps are the camshaft PS. Hope this makes sense here.
first of all your fault beeps IMO are from your CAM sensor as the PCM 555 is not receiving the correct cam PS signal / reluctor wheel on the gear / the new cam sensor you installed is not reading nor sending the proper input signal to the PCM hence the output signals from the PCM is throwing a fault code / warning beeps along with the engine runs like crap. just saying.
Next the tech BS of this and what is going on. Hope my words make sense of all this.
the cam PS and the crank PS supply the PCM with timing and RPM information as inputs to the PCM 555. When a failure takes place in both and one of these circuits, the engine will run rough and backfire and can even shut down. First and foremost check for continuity between the sensor(s) and the PCM first of all to make sure that is OK plus the connectors / connections are in very good shape with no rust or moisture on them.
It is best to test the sensors as well for resistance values. Most marine OEM's require testing them (sensors) at around 70 degrees for proper resistance values FYI so room temp would be good to.
Values are
camshaft PS - A to B 24.04 mohms then B to C 24.05 mohms
crankshaft PS - A to B 23.2 mohms then B to C 23.21 mohms
I have posted this info before up here.
here is the kicker with Merc and important info for many who even scan the engine and get nothing.
all PCM 555 software prior to level 091, a malfunction with the crankshaft PS and or the Camshaft PS will NOT set a FAULT. With level 091 (PCM 555) if the CAMSHAFT PS is bad or faultly in any shape or form however and does not send the a signal and or the proper signal to the PCM - the engine will backfire and at times will not start in some cases.
Here is what can take place as stop cranking the engine over and then try to restart the engine - operating the engine for 20 seconds to set faults. the (fault) warning alarm will be set 2 beeps per minute. With that said IMO your 2 beeps are the camshaft PS. Hope this makes sense here.
How do you find the version of the PCM?
