Will An Idle Stabilizer Kill My Motor?

Engine is a 95’ SN 0G0*** Carb 175. Ok, so I’m waiting on parts and I’m bored. I’ve been looking at threads for hours on this. My motor has the idle stabilization module on it. The one I believe that doesn’t have an advance feature. I haven’t messed with my top end timing. It’s where it was when I got it. Does this module only have the idle advance feature and nothing for WOT, and if it fails, will my engine be ok? Also, I can’t seem to find Mercury SB 91-35 to see what they set the timing at for it. That was the SB that changed the advance module for a idle module. Manual states crank idle at 20 degrees cranking and 19 WOT which leads me to believe that it’s for an advance module.

If im correct on this,Idle timing should be around 0 to 12 atdc,or where it's happy in water in gear but I've never heard of 20 degrees on idle timing ,someone that can explain it little better will chime in soon ,idle stabilizer needs be n trash can,and can advance your timing if it goes out , there's usually a sticker on air box that has ur timing info

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Originally Posted by Merclover

If im correct on this,Idle timing should be around 0 to 12 atdc,or where it's happy in water in gear but I've never heard of 20 degrees on idle timing ,someone that can explain it little better will chime in soon ,idle stabilizer needs be n trash can,and can advance your timing if it goes out , there's usually a sticker on air box that has ur timing info

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Sorry, but a little clarification. It’s 20 degrees cranking on the starter with the throttle fully advanced and the timing arm against the stop per the manual.

OK it will advance it to 25ish at wot ,that sounds better,but to answer ur question, needs be took off motor and reset idle and wot timing ,need to confirm ur motor timing specs tho

So I gather some information that people timing to 25 degrees run premium fuel. I’m just one of them guys with sticks hanging off the side of a 20 foot cuddy cabin. She does 46 MPH at 5800 RPM with a light load and little fuel. I’m very satisfied with that. Also, I read the 25 degrees is preferred for running wide open and it doesn’t like to be bogged down. I’m usually loaded up to fish and cruise part throttle, conservatively at 4500 - 5000 RPM and about 34-40 MPH. is there a preferred timing less than the 25 degrees for a regular Joe like me?

Manual lists maximum timing for Model 175 Carb:
At cranking speed: 20 degrees BTDC
WOT: 19 degrees BTDC.

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Originally Posted by Capnmoench

Manual lists maximum timing for Model 175 Carb:
At cranking speed: 20 degrees BTDC
WOT: 19 degrees BTDC.

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those are the settings with idle stabilizer in Place. If you get rid of the idle stabilizer like I’m doing right now you set it to 25 wot. I’ve been doing a ton of reading on it. At least that’s the case with my 95'225 promax

Your Promax is listed in my manual as supposed to be set to 25 degrees BTDC in the same spec listings.

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Originally Posted by Bunger

those are the settings with idle stabilizer in Place. If you get rid of the idle stabilizer like I’m doing right now you set it to 25 wot. I’ve been doing a ton of reading on it. At least that’s the case with my 95'225 promax

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Model 200/225 PRO MAX/SUPER MAGNUM
Full Throttle RPM Range 6200-6500
Idle RPM (in Forward Gear) 600-700
Maximum Timing:
@ Cranking Speed (Note) 25° BTDC
Idle Speed/Pickup Timing 0°-9° ATDC
Spark Plug NGK-BU8H
Firing Order 1-2-3-4-5-6
NOTE: Early model 200 engines equipped with the
detonation module should set the timing at 20°
BTDC.

Quote:

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Originally Posted by Capnmoench

Model 200/225 PRO MAX/SUPER MAGNUM
Full Throttle RPM Range 6200-6500
Idle RPM (in Forward Gear) 600-700
Maximum Timing:
@ Cranking Speed (Note) 25° BTDC
Idle Speed/Pickup Timing 0°-9° ATDC
Spark Plug NGK-BU8H
Firing Order 1-2-3-4-5-6
NOTE: Early model 200 engines equipped with the
detonation module should set the timing at 20°
BTDC.

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I just checked mine mine I have t even opened yet and it said 23° btdc for
my promax

This has been what's been throwing me off. So, you disconnect the idle stabilizer from the switch boxes, some models you add the 3 degrees, but mine it says to set to what's listed in the spec which is 20 degrees.

Models equipped with Idle Stabilizer Shift Kit Accessory
(P/N 87-814281A1), excluding Mercury
XR6, Mariner Magnum llI and 175 require maximum
timing at cranking speed in neutral to be retarded
3° from specifications listed on page 2C-1.
Note, Stabilizer Shift Kit is standard on XR6, Magnum
llI and 175 models and already has retarded
timing degrees calibrated into specifications
listed on page 2C-1.

1. Connect timing light to No 1 spark plug lead (TOP
STARBOARD BANK).

2. With engine in neutral, move throttle lever to
place maximum spark advance screw (a) against
stop. Crank engine with starter motor and adjust
maximum spark advance timing mark (see specifications
on page 2C-1) with timing pointer. Due
to the spark advance/retardation characteristics
of this ignition system, this cranking speed adjustment
will increase (XR6, Magnum llI and 175)
or decrease (135,150 and 200) timing at 5000
RPM and above. Retighten jam nut on adjustment
screw.

I have a 1995 Merc 135 carbed motor and i have idle timing at around 2 degrees ATDC and wide open throttle cranking rpm's set AT 20 btdc, my idle stabilizer has been in the trash for 2 years, i run 87 octane gas.

This is the kind of info I get reading the forums. Numbers all over the place.

You’re idle stabilizer should have three wires, red, black, and white with a black tracer. The red wire attaches to a switch box red stator lead, black goes to ground, and the white with black tracer goes to the bias wires on the switch box, which are tethered together from the inside switchbox to the outside.(top rear Switchbox terminal) By measuring voltage on the red wire the module senses rpm dropping below 500 RPM, and applies a partial ground to the bias circuit, electronically advancing the timing and preventing the motor from stalling . This module has nothing to do with full throttle timing, otherwise known as maximum timing advance. If this module fails, It can advance your motors timing causing failure. If the motor is tuned well it should not need this module.
There is another module used on some of these motors that has four wires and is the double duty module, idol stabilizer and maximum timing advance. This module works in the same way as the idol stabilizer , But also advances the timing 4or5° after the motor reaches 5000 RPM. This module may fail in the same way as the idle stabilizer may fail, and it also confuses maximum timing advance, so we Often delete them, Chris

Thanks Chris. That’s what I was thinking I was reading in the manual that my initial setting is figured into the chart for my motor and that the “electrical curve” of the higher rotation naturally advances the timing above 5000 RPM like stated in paragraph 2. Not the idle stabilization module. I will leave the timing alone and ditch the module. That will be the last “technological” add-on to pull. Now she’s bare bones, but hopefully bulletproof for 20 mile treks halibut and tuna fishing.