Timing question 81' 115 evinrude. Please help...

[mrracer98]

Hey all, question for you-

I just got done rebuilding this motor and have plenty of mechanics experience but lacking on these evinrude timing systems. Now I understand how to adjust the timing with the timing stop screws... but here is the problem.

It runs great other than backfiring, this is NOT a carb problem it is timing. All coils are working properly and hooked up correctly. Unfortunatley the tach is bad, but from a harmonic manual tach at about 1400 RPM it is running about 12 degrees of timing on the wheel. via timing light on #1. at that timing, it backfires a bit. now if I manually push the advance arm back to about 6-8 degrees on the timing light, it runs perfect.

Also, I do NOT have a timing stop check tool thingie from OMC... but TDC at #1 is right on the TDC mark on the flywheel indicator.

Any suggestions? Is there anyway to get it to run good on the low end and idle so I can get it to the lake and then check the running timing at 4500 rpm...

It does seems to run better the faster the idle gets/faster the prop spins in gear, so I must be close.

 

[petryshyn]

Re: Timing question 81' 115 evinrude. Please help...

Read this timing method (http://forums.iboats.com/showthread.php?t=228183)
You really do need a manual to do a proper "link & sync" on that engine

 

[mrracer98]

Re: Timing question 81' 115 evinrude. Please help...

Hey, thanks. I do have a manuel thought it is a 1978 model, and my engine is an 81', most things are the same, except for a few things here and there. So basically there is no need to set timing other than the WOT method? i.e. once you set the timing correctly at 4500 RPM, everything else will fall into place?

Another question is how can I tell if my engine has the "fast start feature" as I assume mine does because I cannot locate a choke on it... yet it does "choke" when you push in the key. It does not have a chose selonoid as the older models did...

 

[petryshyn]

Re: Timing question 81' 115 evinrude. Please help...

follow the manual for the link and sync, but when it comes time to check max timing, use the WOT method. There are a couple of linkages that may need adjusting. Idle timing should fall into place but should be checked on that model.
I doubt you have the fast start feature. You don't have a choke. Instead, they use a primer solenoid to supply addition fuel . (http://forums.iboats.com/showthread.php?t=305323)

 

[tashasdaddy]

Re: Timing question 81' 115 evinrude. Please help...

Joe Reeves timing procedure is the best i have ever used.

 

[mrracer98]

Re: Timing question 81' 115 evinrude. Please help...

So does anyone know if there is an actual timing spec for an idle RPM range? (i.e. 12 degrees at 600 RPM) or something of that nature?

Thanks to all that have helped. I did get the choke thing figured out and no it does not have the fast start feature. Today I will go ahead with the joe reeves method of timing... Hopefully right now it is way off, as I am hoping this will fix my problem.

The real confusion I have is that even though I adjust my WOT "Full spark adjustment screw" I still have a idle speed adjustment screw, that must actually change the idle via adjusting timing only? is that correct?

If I am right on my assumption than I should be able to check the timing on my other (properly functioning 78' 85 hp) to get me in the ball park.

 

[tashasdaddy]

Re: Timing question 81' 115 evinrude. Please help...

use Joes procedure, low speed timing will take care of itself. you have an idle speed stop screw, that sets the idle rpms. that is the beauty of Joes procedure.

 

[petryshyn]

Re: Timing question 81' 115 evinrude. Please help...

While the "Joe Reeves" method is a safe and easy way to check max timing advance, it does not replace the synchronization procedures laid out by the manufacturer. Yes, it addresses maximum timing , but it does not assure that the non-linear advance curve provided by the ramp linkage is placed in proper sequence throughout the throttles positions. That is why it is important to follow the manufacturers recommendations for synchronization, substituting the max timing check only. If the adjustments were never messed with, the "Joe Reeves" method would be all you need to check, but who's to say if they'd been messed with........

 

[tashasdaddy]

Re: Timing question 81' 115 evinrude. Please help...

agree.

 

[mrracer98]

Re: Timing question 81' 115 evinrude. Please help...

GRRRRRRR... I don't get this.

Here is the problem. I did the joe reeves timing method.. fine, done. I linked and syncd befre I did it. Check. Motor starts good, (I dont have a tach, but I do have this same motor in 78 85hp flavor) So I can tell ROUGHLY where it should be at. Well I can tell you it runs good when idleing fast, probably about 1500ish whatever that RPM is, the timing shows about 12 degrees.... I start the RPM's back down and Im not sure if it is detonating or backfiring, but it is not normal. I check the timing it gets to TDC-4 or 5 degrees as what the manual calls for, but it barly runs, and not consistently i.e. it will run, backfire run, and quit... sounds almost too low of RPM. It seems to run great in gear, and like I said with a few RPM under it. I have linked and syncd per manual several times, the ramp is working properly as it should at least per what the manual says and what my 85hp functions like.

I jsut dont see what I am missing other that not having the OMC Special tool piston stop tool that it calls for to verify the timing indicator. However as I stated in the first post TDC with #1 is TDC on the flywheel and indicator... so I dont know how that could be off. WHAT AM I MISSING?

The only thing is it seems that I had to adjust the trunion knob for the throttle cable up quite a bit, but everything seems to function corectly i.e. hit the WOT stop, back to the idle stops, and moves freely...

ANY IDEAS please?

 

[mrracer98]

Re: Timing question 81' 115 evinrude. Please help...

^^^

 

[iwombat]

Re: Timing question 81' 115 evinrude. Please help...

Even if your link&sync wasn't right, or your max timing was off there's no way it should be backfiring. I'm guessing your powerpacs are double-firing, or your timer base is malfunctioning. Or your connections have been reversed somehow. You can check that by hooking a timing light up to each cylinder and making sure it's firing only when it's supposed to.

 

[mrracer98]

Re: Timing question 81' 115 evinrude. Please help...

Even if your link&sync wasn't right, or your max timing was off there's no way it should be backfiring. I'm guessing your powerpacs are double-firing, or your timer base is malfunctioning. Or you're connections have been reversed somehow. You can check that by hooking a timing light up to each cylinder and making sure it's firing only when it's supposed to.

How would I go about that with a timing light? Marking the flywheel like a clock and just making sure they are not firing on the casted degree marks on the flywheel?

 

[petryshyn]

Re: Timing question 81' 115 evinrude. Please help...

Lean mixtures will also cause backfires.
- Did you clean the carbs?
- Are both throttle valves completely closed at idle?
- Are you sure its a backfire, not a misfire?
- Are they the right plugs?

 

[mrracer98]

Re: Timing question 81' 115 evinrude. Please help...

Thank you to everyone that helped me! I got it figured out. The number 2 and number 4 coil pin plugs were crossed. I have no idea why, as I knew little history of the motor other than it just "blew up" before I rebuilt it. I am kinda mad at myself as I did notice it before based on the wiring diagram, but I am using a 3 year older manual and I didnt think to double check. Thanks everyone... It runs like a champ now, just need to get the TNT going!

 

[iwombat]

Re: Timing question 81' 115 evinrude. Please help...

woo hoo!