1975 merc 650 timing, idle and WOT?

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crittrbug

Cadet
Joined
Jul 4, 2003
Messages
9
I am not sure how to set up the timing, in the book, and on the engine it tells me that max timing advance is 23 degrees, however there is an adjustment for idle to max. I don't know what the idle adjust is supposed to be. On the power head it says ".125 degrees BTDC", and right under that it says "23 degrees". In the book if I do what they describe I would be adjusting the idle timing when I am doing the max timing. Does this mean that the timing never changes, or does this mean that I should buy the book from Merc, instead of the after market book I have. I would just like to know what my idle timing should be set at.
 
N

NathanY

Commander
Joined
Mar 16, 2002
Messages
2,408
Re: 1975 merc 650 timing, idle and WOT?

I have the same motor as you. You really need to read your manual VERY closely on timing procedure. It is critical that it is set perfectly or you will burn #2. My manual has 3 pages on the prcedure just for this motor. It would take me too long to type it here.
 
C

crittrbug

Cadet
Joined
Jul 4, 2003
Messages
9
Re: 1975 merc 650 timing, idle and WOT?

^ So I did it by the book exactly and it seems to idle way too high. Is it possible that my carbs need to be cleaned (they sat for about a year and a half). If so can I just get away with a fuel additive or spray, or should I rip them apart?
 
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RICKRICK1

Ensign
Joined
Jun 24, 2002
Messages
926
Re: 1975 merc 650 timing, idle and WOT?

crittrbug donot repeat donot use atumotive carb sprays to clean your carbs with the motor running as this removes the oil used to lubricate the bearings. In most caes you will need to overhaul the carbs by removing them. You can use spray cleaners, but soaking the bowls and parts in a good carb cleaning solution over night will clean them best. Us the spray cleaners to blow out all orfices if you do not have compressed air available. be sure and remove all rubber parts (check needle and seat) before soaking. Besure and set the float properly. Also do a link and synk of throttle.
 
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