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Question with Timing

yzf125

yzf125

Contributing Member
Hey guys, I wanted to check timing on my 02 Mercury 75hp 2 stroke. Now the sticker on the side of the motor says " 2 BTDC / 18 BTDC " I am assuming this is @ cranking settings ? So I checked and came up with Idle cranking at 5 and WOT at 20, Is this ok ?
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Thanks for the reply, These readings are @ cranking speed correct and not running ? That is how I did them, removed plugs and turned over motor with throttle cable disconnected.

So that 20 degree reading I got should be 18 ? I read in a manual that says (" due to the advance characteristic of this ignition system, this cranking speed adjustment will automatically be reduced by 2° at an engine speed of 3000 RPM ") So wouldnt the cranking timing reading of 20 be correct if its reduced by 2 degrees when running at 3000 RPM or is it the other way around , setting it at 18 @ cranking speed would really be 20 if running @ 3000 RPM ?

Thanks.
 
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Found this video about static timing ( cranking ) an outboard engine. Its similar to mine and from what he says and what I understand is that if my Max timing is supposed to be 18 then I need to set it @ 16 ? Seems to also be what the manual was saying.

 
DON'T run it with more timing than recommended. I tend to run a few degrees less than recommended with the crappy gas out there.

Jeff
 
Set it at 20 degrees cranking and it will retard to 18 degrees at WOT running. Set the idle at 0-4 degrees, the motor will tell you what it wants....
 
I've always relied on the manual, and here's Mercurys' idea on how to do a static timing: 1st, (THIS IS IMPORTANT!!)sync the carbs and remove the throttle cable. Remove the spark plugs and ground them. Connect your timing light to #1 plug lead. To set the idle timing- make sure your battery is fully charged. Hold the throttle arm at idle position and crank the engine in neutral. Adjust the idle timing screw to align 2 degrees btdc timing mark with the timing pointer.
To set the maximum timing advance, hold the throttle arm against the maximum advance stop, crank the engine, and align the timing pointer 2 degrees higher than the recommended maximum advance as per your info sticker- in your case, set it at 20 degrees btdc. The ignition system compensates for the extra 2 degrees, and the outboard will be timed correctly (18 degrees at 3000 rpm.)
 
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