mercruiser thunderbolt V sensor problem

[bolo78910]

hello everyone. mercruiser 5.0L is eating up distributor sensor. we went through three this season so far.

i start the boat last week is start fine went back today and all i get is crank cranking but no start.
i barrow one form my friend it start right up. what is killing this sensor?????? engine serial number is 0L612762
thanks for any input.

 

[Don S]

Re: mercruiser thunderbolt V sensor problem

Check the distributor shaft bushings. If they are worn out and the shaft is moving back and forth, the rotor could be hitting the sensor.

 

[UncleWillie]

Re: mercruiser thunderbolt V sensor problem

Given the lack of any specific knowledge of the engine; A wild, in the dark guess would be.....

Is this engine supposed to have an Ignition Coil Ballast Resistor that is missing?

Be more specific to the details of the ignition system.
What Sensor? What Coil? What Distributor? Picture?

 

[Don S]

Re: mercruiser thunderbolt V sensor problem

Given the lack of any specific knowledge of the engine; A wild, in the dark guess would be.....

Is this engine supposed to have an Ignition Coil Ballast Resistor that is missing?

Be more specific to the details of the ignition system.
What Sensor? What Coil? What Distributor? Picture?

It's a Thunderbolt V iginition system, and he has the engine SN,
how much more specific can he get ????????????????

The sensor is inside the distributor, same place as it has always been in Thunderbolt ignition systems.

 

[bolo78910]

Re: mercruiser thunderbolt V sensor problem

thans don i will check on the shaft bushing . ok i am wondering sometimes we start the boat and fogot to turn off the on board battery charger. would that provider a over charge from the engine alternator?/

 

[Don S]

Re: mercruiser thunderbolt V sensor problem

thans don i will check on the shaft bushing . ok i am wondering sometimes we start the boat and fogot to turn off the on board battery charger. would that provider a over charge from the engine alternator?/

Shouldn't be a problem.

 

[woody66912]

Re: mercruiser thunderbolt V sensor problem

Hey don, those rotors come off real hard, if it was bent upon removal the first time could that act like a bent shaft?.

 

[Don S]

Re: mercruiser thunderbolt V sensor problem

Sure

 

[achris]

Re: mercruiser thunderbolt V sensor problem

If you can't find a mechanical reason, then you'll need to start looking to the electrical side of things. The first place I would start is checking the distributor body for proper connection (electrically) to the engine block. I'd go so far as to run a dedicated ground wire. Also check the main negative lead from the battery to the engine block. As the amplifier module is also mounted to the dissy body this becomes even more critical. The next step would be to check and verify all the wires into the amplifier and sensor. A resistive lead could easily be causing your problem. The next thing I'd be checking is the battery leads. They need to be clean and tight, with no wing nuts on the terminals. If you have a bad connection it can cause spikes and noise that could also account for dead sensors.

Chris.......

 

[bolo78910]

Re: mercruiser thunderbolt V sensor problem

thanks guys about the grounding off the sensor you might be on to something there i will just take the ground straight from the battery neg side and see.

 

[bolo78910]

Re: mercruiser thunderbolt V sensor problem

up date here guys went back to the boat today, first thing i did was i remove the distributor madule ground wire and ground it on the negative batttery post and vroom it start right up. live and learn something every day. thanks don and the guys for all the inputs. have a great holiday.

 

[bolo78910]

Re: mercruiser thunderbolt V sensor problem

good thing i did not toss the old ones away he he