Low Speed/high speed or Idle stabilizer

[floater88]

I just got my Merc manual for my 1991 Mercury 200 hp outboard. The manual shows both a low speed/high speed spark advance module and an idle stabilizer module. How do I know which one I have? I'm just trying to learn the procedure for setting my timing correctly for this spring. If I can I may just remove the idle stabilizer if it proves faulty because the motor dies when i'm approaching a dock at low rpms. Thanks

[Whaaaaat]

Throw all that stuff away. Get the tool to mark your flywheel. Bought mine from Jay Smith. Came with clear easy instructions. Then set timing from most advanced cylinder with a timing light.

My 2cents.

[25two.stroke]

Whats you idle speed in gear? Yes, you should ditch the unnecessary modules as they can screw up and kill your motor (temporarily and permanently). Motor should not die comin to a dock and even a failed stabilizer shouldn't cause it to do this, so you probably have something else off. I guess it could, but **typically** when they fail they cause issues in the entire RPM range.

Seeing that you have a '91 200 hp your flywheel should already have timing marks and a pointer on the flywheel cover. You disconnect the bias wire (white wire between the switchboxes) and check your base and WOT timing at cranking speed.

[floater88]

I disconnect the bias wire? I just read through the manual procedure and it didn't say that anywhere. My motor does have the timing marks and pointer. I'm planning on checking the timing in the condition it's in. Once I feel comfortable messing around with it all I will be removing those modules. Thanks

[tlwjkw]

when ya trash "both" modules you will need to build a short white/black jumper to go between bias on both switch boxes.. leave it hooked up ta do anything timin'... after you get linc n sycn done so idle is completely controlled by tha idle circuit of tha carbs (butterflies COMPLETELY shut) make sure you have a slight "gap" between throttle cam and carb roller.. can be jus enought ta let tha roller turn freely up to 3/8".. depends on how you want it to respond, you'll get tha idea.. set idle (idle timin' only) with boat in tha water, in gear with idle timin' only to whatever makes you and tha motor happy.. numbers don't mater!.. set max at 22/23* with stock flywheel...... this will give a kinda safe zone and you'll never see any difference in performance............... jmo

[floater88]

Thanks for the tips. My switch boxes already have that jumper wire in the top left rear connectors. I was wondering if that was normal or someone had already bypassed the two modules?

[tlwjkw]

sounds like it if thats tha only wire on 'em....

[25two.stroke]

The white/black bias wire is on all of them regardless of modules or not. I don't think any modules ever bypassed the bias. You can tell if someone bypassed them if theres more than one wire on the red wire terminal on the switchboxes. If your system is stripped to the bare minimum there will only be one wire on the red and the red/white terminals on the switchbox.

[floater88]

Sorry for the long reply back. I just made myself the dial indicator in a spark plug base to set my TDC. I have the timing light and i'm going to be making a remote starter tonite. I will disconnect the two modules and start from there and report back. Thanks for all help

[floater88]

Ok I've been reading up on this timing thing i'm going to be trying for the first time. When I remove both modules how badly may I screw up the motor while trying to time it right? I'm looking for a way back I guess in case it all goes wrong and I end up putting the modules back on

[25two.stroke]

Taking the modules off should result in no different change in timing. You can't screw anything up. Only the modules being on can screw stuff up. Take the modules off, check the timing to ensure its within the parameters and you are all good. The timing should be fine.

Why are you checking TDC if your flywheel already has marks and I assume you have the plastic cover with the pointer? Have you changed the flywheel or cover and are worried about the pointer not being accurate? It never hurts, but you should not need to use a dial indicator if you have a flywheel with marks and a pointer.

[floater88]

I do have the plastic cover with the pointer. I've messed with all the adjustment screws over the years trying to get the idle a little higher. I'm just following the manual and trying to do everything to spec. I tried to find TDC today and after using the dial indicator I. made it would only go to 0 on the scale marked on the flywheel. Everything i've read sais it should be at the .462 mark. I put it all back together and tried to do the wot cranking to see the timing and the timing light wouldn't even flash on the number one spark plug wire. The timing light does work as I tested it on my truck. Not sure where to go from here.

[tlwjkw]

2. Turn flywheel in a clockwise direction until No. 1piston is at top dead center (TDC). Set dial indicator at “O” (zero) and tighten indicator set screw. (forget "0" after this is done unless ya gotta start over for whatever reason) (3.) Turn flywheel counterclockwise until dial indicator needle is approximately 1/4-turn beyond .462 in.(on dial)., then turn flywheel clockwise so that dial indicator reads .462 in.(on dial) (11.7mm) exactly. (4.) Reposition timing pointer (a) so that timing pointer is aligned with .462 in. mark on timing decal (on flywheel). Retighten pointer attaching screws (b)

[floater88]

I took the boat down to the lake. It started fine. I put a timing light on it at idle and it was showing 10 degrees after tdc. I adjusted it to 8 and turned the idle down as far as it would go without stalling. It idles around 1150 rpms in neutral and drops to 800 in gear. It ran great out on the lake and it topped out at 5600 rpms at about 42 mph. I guess i'm just going to enjoy it the way it is. Thanks for all the tips and help

[tlwjkw]

I adjusted it to 8 and turned the idle down as far as it would go without stalling.

what did you "turn down as far as it would go"???