New Motor - Need some basic help with Timing procedures

[THenning]

Earlier post: https://forums.iboats.com/forum/eng...mercruiser-4-3-overheat-on-plane-water-in-pan

Ended up needing a new motor, Rings blew on #4 and cylinder walls were scored. Head gasket was shot too. Ordered one from Atlantic Marine.

So I have a new engine in the boat. Just for grins I replaced the water pump impeller and water pump housing in the outdrive too. Alpha 1 gen II, The impeller was new this season, but the upper housing had score marks on the top and I am just not going to take any chances. I have a new circulation pump, too.

I have a thunderbolt V ignition, I need to set my timing. I am at 10 Degrees before top dead center.

I am mechanically inclined, however, ignition timing is something I have not done before. I know the basics. I know I need to put the engine into base timing mode by grounding the wire. I know where to connect the light. I DO have a shop tach.

Do I need a Timing light with electronic advance?

If I have a 0 degree mark, what's my procedure?

A "Thunderbolt V for Dummies" Step by step for initial timing would be amazing.

Thanks guys.

 

[alldodge]

Being a 2001 you should have the EST distributor, are you sure its a TB5?
What's the serial number?

 

[THenning]

0M078233 carb cap says thunderbolt v

 

[THenning]

[No message]

 

[alldodge]

Thanks for the SN, its a TB5
Your damper as marks on it showing Before and After TDC. You want 10 BTDC
Mark the damper with white grease pencil or chalk

Setting Base Ignition Timing
1. Connect timing light to number 1 spark plug. Connect timing light power supply leads (if applicable) to 12 volt source.

2. Connect a shop tachometer to engine.

3. Using a jumper wire, connect the ignition system timing lead “13” (PUR/WHT wire) to a good engine ground (–). This locks the ignition module into the “Base Timing Mode”.

4. Start engine and run at normal idle speed. Allow engine to reach normal operating temperature.

5. Aim timing light at timing tab, located on the timing gear cover and crankshaft torsional damper.

6. Adjust timing using the conventional method.

IMPORTANT: Be sure to disconnect the jumper wire from the ignition system test terminal before attempting to resume normal operations. If the jumper wire is left in place, the ignition module will operate in the “Base Timing Mode”. This
means that the additional timing advance features would not function.

7. Make sure that the distributor has been tightened. Remove the jumper wire from the timing terminal.

8. Stop engine and remove timing light.

 

[THenning]

SO the tab in base timing mode should hit the mark at 10 degrees before tdc at idle ~650 RPM once up to temp?

 

[alldodge]

Yes

 

[THenning]

That's What I was missing. Should I set the Timing light at 10 Degrees Advance or keep @ 0? Thanks a ton.

 

[alldodge]

If you have an advance timing light set it on 10*BTDC and match tab notch with damper notch.

Your damper might have degree markings so could use a regular timing light and mark the 10* on damper