Force 125 Hp 1258F8B Reinstalling Timing advance adjustmer

[MuskyHunterDave]

Where the throttle linkage advances the timing there is an adjustment just under the flywheel which is a threaded plastic block with a piece of allthread & lock nut that advances the timeing as you throttle up (right?). I saw that the plastic piece the adjuster goes through had a crack in it, so I removed it and repaired it, but I now need to know How to readjust the timing advance once I reinstall the adjuster.

I was also curious (in the event I need to) is there a start point when adjusting the carbs ?? Say all the way in and 3 turns out ?? or ??

Is there somewhere online with service manual info on this engine, as I am waiting for a manual to arrive.

Thanks a lot for all the advice

 

[Frank Acampora]

Re: Force 125 Hp 1258F8B Reinstalling Timing advance adjustmer

Aha! You didn't mark the threads before you removed the plastic end--naughty boy.

Start with a gap between the two plastic ends of about 1/2 inch. Run the engine with a timing light. The marks on the flywheel rim should align with the index pointer. Approx 0 plus or minus 2 deg at idle, and 30 deg advanced at wide open throttle. If your flywheel has several marks grouped near the WOT, the long or center line is 30 deg. Closing the gap retards, opening advances. You must stop engine and change setting then restart and check timing. You may need to do this several times to get correct timing. If you static time the engine by cranking but not starting, set timing to 28 deg so running timing will be 30 deg BTDC.

 

[MuskyHunterDave]

Re: Force 125 Hp 1258F8B Reinstalling Timing advance adjustmer

Yea I blundered that . . . . Didn't cross my mind till I went to put it back together.

How much thread should be sticking out at the point (where you adjust it) when I start threading it (reverse threads) into the timing arm (otherEnd )??

Thanks for all the help

 

[MuskyHunterDave]

Re: Force 125 Hp 1258F8B Reinstalling Timing advance adjustmer

Hello. . . . Another question

Can the motor be run at WOT hooked up to the hose cups in the yard to test the timing at WOT or should I take it to the lake as I don't have a test prop. OR once the idle timing is set to + or - 2 degrees from 0 will it atomatically be right for the advized 30 degree advance for WOT ?

I see there is a group of 3 marks with the middle mark being longer, and you said the middle longer mark is the 30 deg advance mark, so then there is a single mark about 2" to the right of those 3, is that the 0 mark ?

What is the prefered Idle RPM for this motor ?

One other thing, I had it running last night, and it was running a little ruff, but when individually revving up the top carb it sounded good and ready to throttle up where when I did it to the bottom carb it was stuttering and not reving up properly, what would that indicate ?? I pulled the bottom carb, and the float was a little above level when inverted, so I readjusted the float to level, and reinstalled it, but was unable to run it as it was getting late.

I asked prior, but was still curious what the Standard starting point is for adjusting the airflow screw on the carbs ???

Thanks again for all the advice, this forum is priceless.

 

[Frank Acampora]

Re: Force 125 Hp 1258F8B Reinstalling Timing advance adjustmer

You can NOT run at WOT in the driveway because with no load on the prop, you will over rev.

Hard to say how much should be sticking out--it varies. When you put it back together, try to have both sets of threads showing about the same amount (centered between the ends)

0 deg at idle is the starting point. Yes the single mark is Top Dead Center or 0 deg. It does NOT automatically set WOT at 30 deg. The important setting is 30 deg at WOT. When you adjust for proper idle 600-700 RPM in forward gear in the water. the idle timing may not necessarily be at 0

Starting point to adjust carb mixture is 1 1/4 turns out from lightly seated.

 

[MuskyHunterDave]

Re: Force 125 Hp 1258F8B Reinstalling Timing advance adjustmer

Okay, So I set the timing at 0 then set the forward idle to 600 - 700, and then run the motor, and check with the light (onthe lake?) at WOT then make adjustments to bring it to the Center Long mark (of the 3 cluster) which you say is the 30 mark. How hard is it to get the light to read whille at WOT throttle across the Lake ?? any suggestions ??

You stated: "Starting point to adjust carb mixture is 1 1/4 turns out from lightly seated."

What is the fine tune adjustment procedure from there for the carbs to get them dialed in ??

Your assistance is priceless, and I cannot thank you enough for all the advice !!

Dave

 

[laadeebug]

Re: Force 125 Hp 1258F8B Reinstalling Timing advance adjustmer

My boyfriend says this is exactly the info we need to set the timing for our Force 125 but I found this thread because we are having trouble finding the actual plastic piece that guides the timing adjuster screw. Can you give any insight on where to get it. We don't know what its called exactly. I know this thread is old but I'm keeping my fingers crossed! Thanks!

 

[pnwboat]

Re: Force 125 Hp 1258F8B Reinstalling Timing advance adjustmer

Here you go. There are two plastic pieces. Items 18 and 21.

Mercury, Mercruiser, Force, etc. - TOWERSHAFT AND THROTTLE LINKAGE (0E009500 - 0E093699) - 120 H.P.

FYI..... You really should start your own new thread instead of tacking on to such an old thread.

 

[laadeebug]

Re: Force 125 Hp 1258F8B Reinstalling Timing advance adjustmer

This is exacly what we needed to find the part and have now ordered it from the website. Thanks for responding to my question! Next time I will start my own instead of adding to an old but I'm glad it worked! :joyous:

 

[flower2]

Re: Force 125 Hp 1258F8B Reinstalling Timing advance adjustmer

Aha! You didn't mark the threads before you removed the plastic end--naughty boy.

Start with a gap between the two plastic ends of about 1/2 inch. Run the engine with a timing light. The marks on the flywheel rim should align with the index pointer. Approx 0 plus or minus 2 deg at idle, and 30 deg advanced at wide open throttle. If your flywheel has several marks grouped near the WOT, the long or center line is 30 deg. Closing the gap retards, opening advances. You must stop engine and change setting then restart and check timing. You may need to do this several times to get correct timing. If you static time the engine by cranking but not starting, set timing to 28 deg so running timing will be 30 deg BTDC.

Will you ruin the coils if you don't ground the plug wires when you crank the engine. You have to remove the plug wires so the engine doesn't start.

 

[jerryjerry05]

Re: Force 125 Hp 1258F8B Reinstalling Timing advance adjustmer

Again start your own thread. You might fry a pack, not so much the coils.
Profile? Location? You might be close to someone who can help.
Also include the motor,year, hp serial#s, model?