Thunderbolt 4 or 5?

baylinerbill

Cadet
Joined
Apr 28, 2008
Messages
22
Ok, so the boat is running great after the new engine install

Today i was fixing a little throttle linkage issue and set idle to 700 rpm and now the throttle returns the engine to that. I had the timing light right there so i threw it on to look to make sure it was set at 8 BTDC. Well it was but every 10-15 sec it would jump around. I thought I had a thunderbolt 4 ignition, but what is the way to tell if you have a thunderbolt 5?

1997 merc 4.3lx Gen+ Serial 0K026503
Alpha one gen2 outdrive
(No Knock sensor behind the module)

I searched around and can't find anything more than 5 may have a knock sensor.

thanks all
 

John_S

Rear Admiral
Joined
Jun 21, 2004
Messages
4,269
Re: Thunderbolt 4 or 5?

Should be thunderbolt v. Need to set in base mode before starting engine.
 

baylinerbill

Cadet
Joined
Apr 28, 2008
Messages
22
Re: Thunderbolt 4 or 5?

thanks imported_John_S,

Just for my own knowledge, is it the year, or serial number that determines?
 

John_S

Rear Admiral
Joined
Jun 21, 2004
Messages
4,269
Re: Thunderbolt 4 or 5?

Serial Number. It switched somewhere in the "F" serial numbers.

Look for the purple/white white with plug.
 

baylinerbill

Cadet
Joined
Apr 28, 2008
Messages
22
Re: Thunderbolt 4 or 5?

Great thanks, i am going to try it when i get home form work. will let everyone know the results.
 
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