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[Chris.gr]

My engine (Mercruiser v8 carb 5.0l) does not start and the tachometer goes backwards. Could someone help me?

 

[Eric 3.7LX Alpha 1]

Your gonna need to give us more to go on. Year, serial number on engine, type of ignition.

 

[Bondo]

My engine (Mercruiser v8 carb 5.0l) does not start and the tachometer goes backwards. Could someone help me?

Ayuh,.... Welcome Aboard,..... Just a shot in the dark,......
Disconnect the grey wires, the tach feed, from the ignition coil, 'n try it,.....

 

[Chris.gr]

My engine (Mercruiser v8 carb 5.0l) does not start and the tachometer goes backwards. Could someone help me?

One more video from my voltmeter

Your gonna need to give us more to go on. Year, serial number on engine, type of ignition.

1995
Ser.no. 0F418269
Attached photo the ignition

 

[Chris.gr]

Your gonna need to give us more to go on. Year, serial number on engine, type of ignition.

1995
Ser.no. 0F418269

 

[dubs283]

Looks like thunderbolt. Have you checked for spark/fuel delivery?

There's a comprehensive guide for troubleshooting a thunderbolt ignition in the stickies, top of forum page

 

[QBhoy]

Is this a newly fitted engine by any chance? Doesn’t sound right cranking there. It’s either cranking the wrong way or something is rubbing or stationary on the belt or something.

 

[alldodge]

SN and your pic shows TB5 ignition with knock module
Run thru this troubleshooting guide "exactly" like it says

 

[Chris.gr]

SN and your pic shows TB5 ignition with knock module
Run thru this troubleshooting guide "exactly" like it says



View attachment 366637

Thanks a lot for the quide . The tachometer gry lead is shorted to the ground (-) . What could i do ?

 

[Chris.gr]

Ayuh,.... Welcome Aboard,..... Just a shot in the dark,......
Disconnect the grey wires, the tach feed, from the ignition coil, 'n try it,.....

Thanks for your reply . I disconnect the grey wires but nothing chance. The problem is still the same .

 

[alldodge]

Thanks a lot for the quide . The tachometer gry lead is shorted to the ground (-) . What could i do ?

Sometimes the Tach can short out so its good practice if there is no spark to disconnect the wire. This didn't help at this time, but we still don't know if its no spark or fuel. Were going down testing for spark first

 

[Chris.gr]

Sometimes the Tach can short out so its good practice if there is no spark to disconnect the wire. This didn't help at this time, but we still don't know if its no spark or fuel. Were going down testing for spark first

Thanks . I disconnect the wire of tach but nothing chance. The problem is still the same .
You can see a video from voltmeter when i try to start.

 

[alldodge]

I don't put a lot of faith in a boats Bat gauge, but your Bat is about dead, can tell that just from the sound of it cranking

Get the Bat charge up and try again

 

[Chris.gr]

I don't put a lot of faith in a boats Bat gauge, but your Bat is about dead, can tell that just from the sound of it cranking

Get the Bat charge up and try again

I have charged the batteries but the problem is still the same.

 

[alldodge]

Then your Bat is bad, the cables and or connections are corroded, or the starter needs replacing.. Have the Bat load tested at local auto parts place

 

[Chris.gr]

Thanks to all of you , i replace the starter and works perfect !!!