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

nola mike

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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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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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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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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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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
 

Mc Tool

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I would as well, hence the post. And yet I think I've done everything correctly.
Is everything tickety boo at the helm end of the cables ....nothing with a bit much free play ? 🙂
I recall ( maybe wrongly ) that there are sometimes options for where on the lever the cables can be fitted so as to be able to adjust the amount of travel the cable gets ....like moving the cable attachment point further from the lever pivot would give more travel . Just thinking that the helm lever assy may have been used on more than one model motor requiring more or less cable travel . Worth a look ? 🙂
 
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nola mike

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Is everything tickety boo at the helm end of the cables ....nothing with a bit much free play ? 🙂
I recall ( maybe wrongly ) that there are sometimes options for where on the lever the cables can be fitted so as to be able to adjust the amount of travel the cable gets ....like moving the cable attachment point further from the lever pivot would give more travel . Just thinking that the helm lever assy may have been used on more than one model motor requiring more or less cable travel . Worth a look ? 🙂
I don't quite speak whatever dialect you speak (though I enjoy it). I think it isn't tickety boo if that's bad. If good then I think it is tickety boo. Yes there are 2 mount points in the box, it's on the one allowing for more travel. I'm surprised that nobody has a definitive answer for this. I found a spec (don't know how reliable it is) for 75 mm of cable travel. I'm going to just make sure that the box will move the cable through it's full range. Brand new cable so that isn't an issue.
 

Mc Tool

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I don't quite speak whatever dialect you speak (though I enjoy it). I think it isn't tickety boo if that's bad. If good then I think it is tickety boo. Yes there are 2 mount points in the box, it's on the one allowing for more travel. I'm surprised that nobody has a definitive answer for this. I found a spec (don't know how reliable it is) for 75 mm of cable travel. I'm going to just make sure that the box will move the cable through it's full range. Brand new cable so that isn't an issue.
😁Yeah, tickety boo means all is as it should be . Its an old fashioned British expression ....god knows where I dug that up from coz its not one I normally use 😁
 

jimmbo

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I'm surprised that nobody has a definitive answer for this.
Keep in Mind, that we don't have your Motor in front of Us, and are going by the Symptoms and Descriptions you provide.
What do the Plugs look like after running?

Looking at the one Pic, the part that secures the Part you adjust the Cable Length with(Trunnion), looks like it signs of Breakage(green arrow pointing to the area). If the Trunnion, is not secure, it might affect how the Linkage is moving
20.jpg
 
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