Timing question 70 hp

maineiac5586

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Feb 14, 2009
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I posted a few posts ago about an 1986 evinrude 3 cylinder 70 hp I am refreshing. I didn't see it run before purchase but it has great potential. I'm stumped about the max timing stopper. I noticed when I move the throttle arm (the big arm the control cable mounts to) the ignition plate moves to max timing (contacts rubber stopper) just as the throttle cam contacts the carb roller. I have researched the adjustment for the throttle cam and roller but does it seem like something may be off with the max timing stopper? I feel like it is screwed out too far. When viewing the max throttle stopper from the port side there is only maybe 2 threads of the adjustment bolt sticking out past the lock nut. Is there a length measurement I can use for that screw as a baseline? Does it seem unusual that the ignition reaches the max timing stopper just as the carbs start to open? I am handy with most aspects of outboards but lacking in this adjustment aspect.i have no way to adjust this on a boat. I am working on it on my stand. Here's a video showing what is going on.

 

F_R

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Jul 7, 2006
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It's supposed to reach full advance before the carbs reach full open. Just how much is the question. If it has been messed with there is no shortcut it must be done in the correct order according to the book. Guessing will only produce poor performance at best or engine damage at worst.
 

maineiac5586

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Feb 14, 2009
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It's supposed to reach full advance before the carbs reach full open. Just how much is the question. If it has been messed with there is no shortcut it must be done in the correct order according to the book. Guessing will only produce poor performance at best or engine damage at worst.
It's hitting full advance stopper with the carbs barely open. I ordered a manual I'll have to give the adjusting a try
 

maineiac5586

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Feb 14, 2009
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So does anyone know if the official video from omc showing timing and sync for 1987 and newer 3 cylinder motors would be close enough for my 1986 70 hp? Seems the same except my throttle cam has 2 marks. Here's the video in question.
 

ct1762@gmail.com

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Jan 17, 2019
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yes its the same. some motors had the 2 mark one doesnt matter. i will say it does look like the max timing advance is far too low. it usually contacts fully around 1/2 of the butterflys opening. Mark flyhweel at the 13 degree mark with nail polish or a visible color.pull and ground the plugs/wires. move throttle to maximum advance. check timing (make sure timing pointer properly set with piston stop tool) while cranking the motor. again should be 13 degrees or so by this method. when running under high rpm, timing will advance to its correct 17 degrees if set properly. this way you arent pulling your hair out. just make sure max advance is open so that roll pins on the carbs are all exactly horizontal.
 

jimmbo

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May 24, 2004
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12,944
Over the past 45 yrs, I keeps seeing many people thinking that these 2 stroke outboards, are set up and tuned like their older cars. Case in point is setting of the Idle Speed. Far too many backyard mechanics will fiddle with the Throttle Plate position, thus messing up the Sync between Fuel and Ignition. Others try to set Timing at Idle, which there is no spec on any of the older 2 Strokes.
The linkages between Spark Timing and Carb opening, allowed the timing to be fully advanced with little or no Carb opening, so when the Throttle Lever is pulled back a bit from WOT, the engine can get much better Economy of Operation.
 

maineiac5586

Chief Petty Officer
Joined
Feb 14, 2009
Messages
623
Over the past 45 yrs, I keeps seeing many people thinking that these 2 stroke outboards, are set up and tuned like their older cars. Case in point is setting of the Idle Speed. Far too many backyard mechanics will fiddle with the Throttle Plate position, thus messing up the Sync between Fuel and Ignition. Others try to set Timing at Idle, which there is no spec on any of the older 2 Strokes.
The linkages between Spark Timing and Carb opening, allowed the timing to be fully advanced with little or no Carb opening, so when the Throttle Lever is pulled back a bit from WOT, the engine can get much better Economy of Operation.
Thank you for that info
 

maineiac5586

Chief Petty Officer
Joined
Feb 14, 2009
Messages
623
Over the past 45 yrs, I keeps seeing many people thinking that these 2 stroke outboards, are set up and tuned like their older cars. Case in point is setting of the Idle Speed. Far too many backyard mechanics will fiddle with the Throttle Plate position, thus messing up the Sync between Fuel and Ignition. Others try to set Timing at Idle, which there is no spec on any of the older 2 Strokes.
The linkages between Spark Timing and Carb opening, allowed the timing to be fully advanced with little or no Carb opening, so when the Throttle Lever is pulled back a bit from WOT, the engine can get much better Economy of Operation.
Ok thanks. Although max Timing on this one is 19 degrees. I set it to 15 degrees per joe reeves method
 

racerone

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Dec 28, 2013
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36,033
Timing on these motors just does NOT go out of adjustment.-----Trouble shooting skills are fading away in the sunset.----Huge repair costs at the local shops force some to diagnose at home. -----Turning this or that in the hope of a magic fix is the wrong approach.
 
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