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Marsh
08-07-2011, 04:58 PM
need to know timing setting for a 1987 merc 188 hp. ford v8.

RicardoMarine
08-08-2011, 12:27 PM
What you actually need to do.... (must do)..., is to see your OEM service manual, and NOT take anyone's advice on such a critical specification...... not unless it can be shown to you from the OEM spec in the correct engine manual.

Not that BASE Advance is all that critical, but the OEM will offer you what the Total Advance should be.
BASE is BASE all day and all week long....., we start on BASE, and we idle on BASE......, but the more critical Ignition Advance will be your TA.

Don't be one of these owners who sets BASE only, and then walks away.

See the OEM specs, and then test this at the RPM given for Full In ignition advance!

.

makomark
08-08-2011, 04:19 PM
2X on verifying the entire set of timing parameters.

The OEM manual shows the base timing at 10 deg BTDC. the advance curve (without the base setting) has a two slope curve, with a max and a min bound. The max shows zero advance at 1000 rpm, 20 deg at 1600 rpm, and flatlines at 26 deg @ 4000 rpm. The min line isn't as clear but shows ~ 22 deg at 4000 rpm with the intermediate point around 18 deg @ 1900 rpm. Also shows WOT @ 3800-4200 rpm. (merc manual #02)

RicardoMarine
08-08-2011, 11:47 PM
Wow, 20 deg at 1,600 rpm seems awfully early to me. That's only 1k rpm above a low idle.

Not necessarily doubting you, Mark... but I am surprised!

makomark
08-09-2011, 01:24 PM
Gotta remember, that's an old ford engine.

I didn't make the timing curve, just sharing what's in the manual.

Also noteworthy, this is the original data provided by mercruiser - no attempt was made to find revisions in Service Bulletins, etc., so use it at your own risk....the fuel that was sold back then is NOT the same as what comes from the nozzle today.