Lync n' Sync, 1987 35 HP Merc

[jslu]

SN #0B177575
Engine running (with 9 pitch prop) tests being done in a large barrel full of water.
Previously set initial timing @3*BTDC
WOT timing @ 21* BTDC
Timing done per Forum procedure
Spark easily jumps 7/16 gap when cranking.
Compression 140 PSI each cylinder
Engine starts and idles in neutral ( ~900 RPM) easily
Initial idle screw mixture @ 1&1/2 turns out from light seating.
Engine stalls when shifting into gear.
Tried re-adjusting idle screw (CCW) for richer mixture, no help.
Engine has Morse throttle & shift control controls (vintage unknown).

I'm interested in what is supposed to happen at the engine re the throttle or spark advance when initially shifted into forward gear. My static observation is that nothing initially happens at my engine. Is this correct? It takes approx 25 degrees of additional throttle rotation at the control before the the affect is at the engine. Is there an adjustment to the correct sequence as to timing and or throttle advance and shift engagement ? Again static observation, engine not running.
I also notice that if I shift aggressively into forward gear (engine running) to ~ 25degree advanced throttle position, that the engine will not stall, but the RPM is too high for this sort of move away from the dock.

I'm thinking the Morse control is not set up right, but I'm open to learned suggestions as to other possibilities.

Thanks,

John

 

[Silvertip]

Re: Lync n' Sync, 1987 35 HP Merc

The idle mixture screw setting is not just 1-1/2 turns out and forget it. That is just a "starting point" and if idle mixture is not set properly the engine may indeed stall when put in gear. Mixture adjustments need to be made with the boat in the water and in gear. Turn the screws (one at a time) in 1/8 turn increments in until the engine gags. Note the position. Then turn it out until the engine gags. Happiness (best idle) is somewhere between those two points. You then repeat the process for the other carbs if more than one. After each 1/8 turn you must pause to let the engine adjust to the new setting. You also need to keep adjusting idle "speed" to keep it at the recommended idle rpm. The sequence of events when moving the lever on the control box is that the first thing that happens is the engine goes into gear. After that it is perfectly normal for a fair amount of travel on the level before the throttle begins picking up. Throttle and spark advance are linked at the engine -- hence the term "link & sync" as the engine requires that spark timing and carburetor opening be synchronized. If that's not set up right performance issues will appear.