Perfectmix

I have searched the forums on how to do this correctly. My Ignition has the purple wire not connected to anything. Do I have to ground this wire? Also how do I tell if the Ign. is TBV or TBIV? Once that is completed, at what RPM does the total advance come in, I have heard 3500 and 4500. I'm pretty sure 34-35 is a safe range for total adv. And is there an ignition module that changes the timing curve and what effect does it have.
Sorry for the redundant questions, I just want to do this right the first time. I really trust the information I get from this sight. Thanks in advance(no pun intented)

Scott

I don't have my book so please don't take the 8* figure as fact!

Ground the purple wire this will lock out the module from keeping the base timing on check with the idle. Set your timing at I think? 8* and your done. If you want check it at 3400 or whatever rpm's it all comes in at and you will find it's right on. I will post the the numbers and written procedure when I am home and have the book in front of me unless someone else has the info.

baja36ft

I THOUGHT ON A 1997-99 (CARB)YOU DON'T HALF TO GROUND A WIRE OUT?? AND ON A 1999 HP500 I THINK
IT IS 12*

35/25

I have '99 HP500's. The base timing is 14 degrees. You have to ground out the purple wire, then make sure the motor is idling no higher than 700 rpm. If it is, lower the idle stop screw on the carb while setting the timing. With the base timing set at 14, the total advance should be 34 degrees at about 3500 rpm. I have found that I have to set my base a tad higher (15 or 16 degrees) to get the 34 total at 3500.

Thunderbolt lV ignitions did not have the purple ground wire since there was no knock sensor in the system or idle speed control.

baja36ft

WHEN I TALKED TO THE MERC TEK HE SAID I DIDN'T HALF TO
GROUND ANY WIRE!!!!

35/25

If you have the purple wire hanging off the back of the distributor with the little rubber plug in it, then you need to ground out this wire to set the base timing. That is the sole purpose of the wire as far as I know. If it is not grounded, the ignition module will constantly be searching for the correct advance to keep the idle at 700 rpm and it will be nearly impossible to set the base timing correctly.

Not to take my word for it, I have the Merc instructions somewhere, like Scott said, at home. You should be able to find on the web by doing a search. As far as the Merc tech telling you otherwise, all I can say is, it depends on who answers the phone when you call them.

Perfectmix

Thanks Guys, I forgot to mention that they were (carb)500's. It does have the purple wire with the plug. Sounds pretty easy to set. I will get it done tonight
By the way, what is the v6 module people speek of? What does it actually do to the timing. Does it just effect the base timing for more advance for a better idle condition? Thanks again

JaayTeee

The v6 module has a shorter advance curve.

It's generally used to help idle quality
on supercharged, or big cammed engines.

Perfectmix

Thanks JaayTeee,
My idle is fine right now. A touch rich actually. I adjusted the air screws last night and hopefully with a slight timing adjustment I can reduce the soot on the back of the boat.

Perfectmix

Well--took the timing light to the boat last night and the timing was dead nuts 14 degrees base and 34 degrees advanced at 3500. Thanks for the help guys