timing 4.3 with thunderbolt ignition

tcline11

Cadet
Joined
Oct 5, 2011
Messages
13
Re: timing 4.3 with thunderbolt ignition

:facepalm: Are literacy rates falling that fast???

Read Item 3...

Jumper wire = short length of wire used to connect one wire to another or to a ground.
Timing lead = Purple/white wire that will put the system into 'Base timing mode' if connected to ground when power is applied to the system.

Always connect or disconnect the timing wire to ground with the ignition key OFF.

Look, it's easy.
1. Engine off. Connect purple/white lead to ground.
2. Start engine and make adjustments where required.
3. Stop engine. Remove purple/white from ground.
4. Have a beer... or 3.

I did everything exactly as the instructions said. I sure the timing is correct now at 10 deg at 650 rpm as the engine manual says. When I unhook the jumper wire the timing advances like it should. When the engine is at around 1800 it shows about 16 deg. of timing. Now when I tried to go out it idles great and when I give it throttle it only gets to about 2000 rpm and starts to run bad and backfires every once in a while. What can I check next.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: timing 4.3 with thunderbolt ignition

Carby or EFI? First of all let's establish what you are working on. Let's start with year, model and serial number.... At the moment we are all just guessing in the dark here....
 

tcline11

Cadet
Joined
Oct 5, 2011
Messages
13
Re: timing 4.3 with thunderbolt ignition

Carby or EFI? First of all let's establish what you are working on. Let's start with year, model and serial number.... At the moment we are all just guessing in the dark here....

It's a 2003 mercruiser 4.3 carburated with thunderbolt 5 ignition. Serial #m625922
 
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