496HO Crank Position Sensor Problems???
03-25-2002, 01:55 PM
#1
Rough Seas Lie Ahead
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496HO Crank Position Sensor Problems???
Two friends with new boats (under 20 hours) with twin 496HO's have both had a crank posisiton sensor switch ( located on the aft port side of engine) fail. Symptoms are; up on plane then around 35-4000 rpm the engine dies. Initially it won''t start back up. After allowing it to cool/sit for 15 minutes or so, it fires up. One boat couldn't get onplane without it happening again. The most recent can plane, run for a minute or two then crank out.
I too have a 496HO and so far no problems during some hard running last summer. Funny thing is, back to back new boats has each had this item fail. I'm wandering if maybe Mercruiser made a bad batch of these things or if maybe there's others having the same problem and another recall is on the horizon?
Any of you guys had this or know of another who has had it???
Rick
I too have a 496HO and so far no problems during some hard running last summer. Funny thing is, back to back new boats has each had this item fail. I'm wandering if maybe Mercruiser made a bad batch of these things or if maybe there's others having the same problem and another recall is on the horizon?
Any of you guys had this or know of another who has had it???
Rick
03-26-2002, 08:17 AM
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Do you know if a recall was in the works or just something we should expect to happen at some point in time? I'm assuming that was a 496 right?
Rick
Rick
03-26-2002, 10:26 AM
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I too am having problems with 496HO's. it started as if it was surging and prgressively got worse until I couldn't keep it running.
Then went to take it to the shop by water and it ran perfect. Only one engine is acting up. Sounds like i might have the same problem.
Then went to take it to the shop by water and it ran perfect. Only one engine is acting up. Sounds like i might have the same problem.
03-26-2002, 11:03 AM
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field fix??
How difficult is it to change these on the water? That sensor likely has a GM part number- it may be worth carrying some sensors and the proper tools- beats getting towed or having an unplanned "Gilligans" Island...
Then again if you had Maryann and Ginger
Then again if you had Maryann and Ginger
03-26-2002, 11:12 AM
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We are seeing an unusual amount of the crank sensors failing on the 496 truck motors. The sensor is very diffacult to replace on the trucks. Engine removal is almost necessary.
03-26-2002, 11:42 AM
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They're simple to get to. They're located on the port rear top of the motor. The first guy I know discovered the sensor problem after the mech troubleshot and was baffeled. Low and behold it was found out the factory changed a sensor once (or alledgedly) so the mech swapped out the one on the good engine and duplicated the problem therefore isolating the problem. Now a month later, another new boat with twins is encountering the same problem. It's got me wandering if I'm to expect it to happen to me sometime this summer.... 
Rick
Rick
