Thunderbolt V Ignition Timing

3

300sflyer

Chief Petty Officer
Joined
Jan 1, 2009
Messages
610
Trying to set the timing on a 1998 Merc 5.7 with a 2 barral carb. The serial # is 0L019480. I know I need to set it in base mode, [ground out the purple and white wire] however when I do that, I do not really see a change in the timing or RPM at idle. Should I? Also, this engine has a plastic timing chain cover, with just one timing mark on the cover. I assume this is right at TDC or "zero" ? My merc manual says it should be timed at 10 degrees BTDC. How does one do this without having the timing marks on the timing chain cover?

Thanks for your help!
 
C

cliffblue

Petty Officer 1st Class
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Oct 26, 2010
Messages
209
Re: Thunderbolt V Ignition Timing

You will need an advance adjustable timing light.
 
3

300sflyer

Chief Petty Officer
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Jan 1, 2009
Messages
610
Re: Thunderbolt V Ignition Timing

Thanks for the info guys! My timing light must be 30+ years old. Perhaps it is time for a new one. :) I suppose I could also just make a mark on the balancer itself at 10 degrees, and line it up with the zero on the timing cover. Would that not give me the same result?

I did not see more than one purple and white wire to ground out, but I will check again to make sure I have the correct wire.
 
90stingray

90stingray

Lieutenant Junior Grade
Joined
Oct 26, 2010
Messages
1,162
Re: Thunderbolt V Ignition Timing

Might take a closer look at your balancer...My balancer has the degree marks on it and the timing cover has just the one arrow.
 
3

300sflyer

Chief Petty Officer
Joined
Jan 1, 2009
Messages
610
Re: Thunderbolt V Ignition Timing

90stingray said:
Might take a closer look at your balancer...My balancer has the degree marks on it and the timing cover has just the one arrow.
Click to expand...

Yup... Saw those when looking closely at it. Made it very easy to mark off 10 degrees, and use my current timing light. All is good. :)
 
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