Merc 200hp timming questions.

[acadian2022]

Good morning all. I working on my Black Max 200 you can refer to engine detail Captain and I worked on this forum and now I'm timming this engine. I will upload sticker that is on the carb cover with specs and my home made diagram question to ensure I'm doing this right. I did disable the black box above the top carburator forgot its actual name so I found true TDC from cylinder no 1 and now aim about to follow my diagram this wirh engine sparkplugs pulled out all grounded using stable DC volt charger to spin de starter at 300 RPM. my currently flywheel marked with vertical line and stamped 462 lines up with True TDC with cylinder no 1 and 11 dots beyond the 462 mark and from my research between 462 and the first punched dot = 30deg ATDC and the space between each dot = 2 deg. so the Idea is to use my caliper to measure 5 dots and mark the flywheel starting at 462 direction ATDC and then for the WOT BTDC 20 deg trottle wide open carb link was done add 10 dot please if possible look at my diagram and let me know if I going to avoid blowing up this sweet engine I thank everyone in advance for your knowledge and help much appreciated

 

[Chris1956]

A service manual and the year of the motor would help.

 

[acadian2022]

Hi Chris. the engine apparently was a custom built let me see if I can copy paste my previous post from this forum to avoid any error as to the help I received to id thos engine

 

[acadian2022]

it under this title Dukedog is the one who help me lots finding out about this engine specifications. in a perfect world I would have a dial indicator 10 to 1 from Mike ( Bucksh..77 company in Florida however I sent a few messages and yet received a reply

​

 

[Chris1956]

You can use a caliper or even a steel ruler to set the timing pointer to TDC. I would expect the timing procedure to be the same as any generic Merc V6. Generally you will want 0-9*ATDC for idle pickup timing and 21*BTDC for max spark advance.

 

[acadian2022]

Hi Chris. so my diagram and specs seems reasonable to you?

 

[Dukedog]

go here:

Mercury Outboard 2.5 and 3.0L V6 and Gearcase FAQ

Timing a 2.5

​

Jay Smith gives the following instructions for setting proper timing on a 2.5 "Insert a dial indicator in # 1 plug hole ( V-6 is located Starbord side top )and rotate the crankshaft CLOCKWISE (with all plugs out) till you establish 0 mark the flywheel adjacent to a stationary pointer . After you've establish O turn the crankshaft COUNTER CLOCK WISE till the dial indicator reads .150" then mark the flywheel at the point where the pointer is dead nuts adjacent to the stationary pointer again that is 25 degrees. ( . 170" is 27 degrees ) Remove your dial indicator then reincert #1 plug and attach plug plug wire then ground all the rest of the plug wires ( I use a coil tester instead of grounding to the block ) attach your timing light on # 1 plug which is screwed in the block, rotate with the starter WITH THE TIMING ARM IN THE LOCKED WIDE OPEN POSITION AT TOTAL TIMING till the spark plug fires and indicates. If timing needs to be adjusted loosen the 7/16 jam nut in the top side of the timing arm and adjust philips headed screw till itswhere you want at WIDE OPEN TIMING( fully advanced ) repeat till it's dead nuts. Also make sure if you have an advancer type timing light it is on 0." (28) Jay makes a great dial indicator for performing this procedure - it is available at http://www.jaysmithracing.com

his is for a 2.5 motor but they are all pretty much tha same,, its best ta have a dial indicator... set WFO timin' at 25 (175's and up hp 21 ta 25 degrees.. up ta you) for your MAX timing.. for idle it can start at "0" + or - a coupla degrees ta get it ta run.. numbers are irrelevant for idle.. after ya get it ta run in tha driveway ya gotta go to tha water ta finalize tha idle.. in tha water, in gear use idle timin' screw only ta set idle rpm and/or speed ta make both you and tha motor "happy"''.. pay no attention to tha numbers...

before ya set any timin' at all make sure everything else (fuel delivery ie: carbs, fuel pump, linkages etc. and all 'lectrics) are all up ta snuff.... tha module is called "idle stabilizer"... its really useless and can be float tested..
ya need ta do it by tha book.. when ya start dreamin' up a "new way" with drawings and such ya askin' for trouble.. ie: removing tha hub is a fine example

track down tha manual i suggested in your other post....... dial indicators aren't Mercuy and/or marine specific...

 

[Chris1956]

You might check that max spark advance spec. Carb motors w/o timing advance modules want 21* or 20* max spark advance.

I would recommend a Merc service manual, rather than deriving a timing set procedure on your own.

 

[acadian2022]

okay thank you all very much all I have for dial indicator is my caliper end and made a insert guide using a sparkplug gutted out and made a stainless steel rod with rounded polish tip comparing my tool and the caliper end hit zero un TDC cylinder no 1 plus the label on the carb cover and my diagram is as best as I can do for now I'm 100 sure I'm at TDC on cylinder no 1 and it line up with the 462 stamp mark on the flywheel when I spin the starter at 300 rpm but with reseach it seems that good but need to move away from 462 mark now and ATDC 2 deg. was able to achieve that yesterday and set my WOT to 20 deg BTDC the engine starts on the first click of the key and sound amazing. yes it idle now around 1000 RPM once I put it in the water last week in gear drops to around 750

 

[acadian2022]

 

[Chris1956]

Doesn't the setting of the timing pointer involve backing the #1 piston down from TDC to .462 inches BTDC? Your timing decal should have that .462" BTDC on it. Just setting the piston to TDC gives a few degrees of error.

That is why I suggested a caliper or steel ruler, as you can add .462 inches to their readings. Your piston stop tool cannot do that, right?

 

[acadian2022]

correction on my previous message apparently 10deg ATDC not 2. hold on going to take pic of the flywheel and explanation to why I need to go 10 deg ATDC. see pictures when I find true TDC for cylinder no 1 it line up with this flywheel 462 mark and line up with the cover needle perfectly however from some reading on line this AM apparently now I need to move away from that 462 Mark to 5 dots ATDC each dot represent 2deg then for the advance WOT its 10 dots length = 20 deg for BTDC I measured 5 dots using my caliper and from line 462 to ATDC direction made a line then from 462 mark added equivalent of 10 dots again using my caliper mark that for the 20 deg BTDC

 

[Chris1956]

Gee, remove all spark plugs. Now set the timing pointer to .462" BTDC decal reading with the #1 piston at a measured .462" BTDC.

When that is done, install #1 spark plug. Install timing light. Crank motor and advance throttle until timing is 0-9*ATDC. Adjust throttle arm linkage so timing doesn't move, and carbs are still closed, but ready to open.

Now advance throttle fully and crank engine. Adjust throttle arm linkage to allow 21* BTDC timing. Set max spark advance stop screw,

Advance throttle fully and make sure carbs open all the way. set throttle stop screw. Set throttle cable preload as the decal says.

You're done!

 

[acadian2022]

yes I think this is what I'm doing just not sure when you say 0-9* please keep in mind I'm a total novice the local shop are so busy and I sure do want to put the boat in the water but been doing my do dillegence for hours on line listen to you guys etc. with all I've done to date before I was going to move forward with my lastest setting I had to come here to run it by you guys the way I see it if I blow up this engine after all of this I still feel I added the chance of not blowing it up by doing my last stop here no pressure now hahahaha my property could still have more boats do

 

[acadian2022]

well engine sounds great thank you all will tested on the water this Saturday

 

[Chris1956]

Gee, a Merc service manual is in order, I would think. Merc has a specific link and synch procedure. I have tried to give you the Readers Digest form of it.

0-9* ATDC is the spec for idle timing of most Mercs with ADI ignition. The key is to get the idle pickup timing in the center of the spec.

The max spark advance is the most important. Max spark advance timing, if more than the spec can damage the engine.

 

[acadian2022]

Ok thank you.