Can't sync my 2003 25 hp 2 stroke...

nola mike

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Apr 22, 2009
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I've NEVER had this thing adjusted correctly, have owned it for 12ish years. Came to me with everything out of spec. Every once in a while I try to adjust it correctly and fail. Another attempt the last few days. It's a remote shift, and the procedure is a bit different than the side/tiller shifts. Here's what I'm doing (picture attached for reference).
1. Disconnect throttle cable
2. Move lever "A" aft until lever hits stop
3. Adjust idle screw until idle cam follower makes contact with idle cam (arrow), then 1 turn in
4. Move "A" forward to WOT until it hits stop. Adjust shift lever "B" so that throttle opens completely.
When I do this and I'm in neutral, "C" and "D" have no aft preload on them, so the throttle doesn't always close all the way, and "C" doesn't return to the timing stop (so timing remains advanced, throttle doesn't close, idle very high). It seems that this isn't solvable unless the throttle cable had more travel. Hoping someone can tell me what/if I'm doing something wrong here.

Timing stuff:
Have a fancy light and cheap HF light. After years of trying to time this thing, I finally realized that using the advance timing feature leads to inaccurate results on a 2 stroke. Also, even though the Bosch light has a 2 stroke feature, the RPMs show double what they are until over 5k. Reflective laser tach also shows double, which I don't get at all. On cylinder #2 the rpms are accurate. I'm getting 5500 at WOT with timing at ~23' at around 3500 rpm. Don't know if an extra 2' of advance will make a difference?
IMG_20220924_130943~2 (1).jpg
 

jimmbo

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May 24, 2004
Messages
14,453
Perhaps the Pivots are a bit dirty, and need cleaning and a bit of fresh Grease. Same goes for the Linkage, and return Spring to the Carb.
What Service Manual are you getting the Link & Sync Info from?
I know some of Mercury Electronic Ignition Boxes would alter the Timing electronically at high Rpm, some would add a bit, others would retard it from what was set at Cracking Speed for WOT
 

nola mike

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Apr 22, 2009
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They used electronic and then changed to mechanical (strange). Very simple advance mechanism. I actually took C/D off and regreased. Throttle return spring is good. Nothing is binding, there's just nothing bringing C/D aft except for the throttle cable.
Screenshot_20260710-201002.png
 

jimmbo

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May 24, 2004
Messages
14,453
You have the Throttle Cable Length adjusted to provide a bit of Preload on the Idle Speed Stop Screw? It will need to be readjusted anytime the Idle Speed is changed. Too Little or No Preload will result in inconsistent Idle Speeds, usually too high, Too Much Preload, it becomes more difficult to shift into Neutral.
 

nola mike

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Apr 22, 2009
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5,924
No, that's the issue. Per the manual the cable is adjusted at WOT. If that's the case then there isn't any preload at idle. If adjusted for idle preload there isn't enough travel to reach WOT
 
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