dead spot on throttle cam 88 Mercury Black Max

[waveskimmer]

I looked thru my manual and could not find any dimension for link you replaced. Did it look identical to what you replaced?
Anyway you have a geometry issue. It needs to be worked out before fine adjusting the link and sync.
I've been thinking about this off and on all evening. The idle screw needs to be turned out and adjust it to look like example in manual. Adjust link to cam for adjustment to stop as stated. Keep working on that until you can see the cam moving the carbs with out running off the end of the cam. Maybe you will need to use the short line on cam to get the range you need. Once you have the needed range of motion then do the link and sync of carb roller and primary pick up timing. The max timing doesn't change unless you move screw or stator link.

Once it is as close as you can get it run on hose. With carb shutters closed adjust primary pick up to obtain an idle about 900.
Double check max timing before you run it off the trailer.

It's something I find easy if it were right in front of me. I hope I have helped you and you get it figured out.

I didn't actually replace the link rod itself, I replaced the anchor barrels as there was a lot of slop and play in the old ones.
I'll be reseting everything back to "spec" on that side of the engine and am going to look for other problems with the slow planing issue. It's "worked" this way in the past (with the dead spot), I only just spotted it while doing the linkNsync and thought it must have something to do with the planing issue. It does however reveal a possible cause for another suspected problem. In the past the engine runs ok at idle, great up top, and crappy right before it goes on plane. between 2000-3000 rpm the engine shakes excessively and warms up a bit. Classic signs of over advanced timing. I think the shape of my current cam is the culprit.

Yes you've huge help and I really appreciate it.

Gonna keep posting here with updates.

[Jim Speros]

I was just trying to interpret what you were sharing and help the best I could. Most every 2 stoke I've worked on has a rough spot in its transition from off idle to mid range. Some worse then others. Some you barely notice and some that would get a lot of attention. I don't know if this is relevant in your situation but, I'll share thought anyway. If the boat is over propped it seems to be more noticeable. Is your boat propped to or real close to the top of its recommended rpm range? If its over propped its forcing the engine to work hard thru the entire range.

[waveskimmer]

Prop is a 14x19p four blade, and when its running right gets to top of operating range pretty quickly.
Reset everything to spec and got to the idle rpm. I've normally set that with the idle pickup screw, but went by the book this time and adjusted idle stop screw to set rpm at about 800 rpm out of gear while idling. Idling in gear was around 600 and strong. Transition was much better maybe since the carbs had a head start and where opened a bit. Will adjust idle rpm in gear to be more around 700 when I have someone with me.