What happens if timing is off?

Cady8special

Seaman
Joined
Aug 24, 2011
Messages
64
I'm planning on checking the timing in my outboard over the next couple of weeks just to make sure it's up to snuff. I have no reason to suspect it's off-- runs well at all RPM's.

What would happen if your timing was off by say 1 degree? What if it was off by say 3 degrees? Would the motor just stop running? Would it run rough? Would it run good at certain RPM's and bad at others?
 

Jlawsen

Master Chief Petty Officer
Joined
Apr 22, 2012
Messages
810
Re: What happens if timing is off?

The base timing on an engine can typically be used to adjust the idle of the engine on a two stroke. As long as the fuel system is funtioning correctly, you can vary that by several degrees and you'll know by the rpm's at idle in gear when you have it right. The WOT timing is pretty critical. If you're low you'll suffer a power loss and probably won't reach max rpms. That will load the engine and no two stroke likes to be run under a hard load. If you've got too much WOT advance dialed in you can easily burn a piston. If you time the motor using the manufacturers procedures according the the manufacturers shop manual then you will not have a problem as long as the fuel delivery system is funtioning correctly. I don't trust any aftermarket shop manual to be correct for any engine I work on. They try to cover too broad a range of models, years and styles.
 

Cady8special

Seaman
Joined
Aug 24, 2011
Messages
64
Re: What happens if timing is off?

Yeah, I have a seloc manual for a 1988 90HP Johnson and I hate it. Way too vague. I've searched the manual high and low for something as simple as how to actually adjust the timing, and I can't find it anywhere. It tells me the steps of checking it, but doesn't tell me what I have to actually do to change the timing. I wish I had a manual of MY motor with detailed pictures. Every picture they show me is of some other size, or other year that looks NOTHING like what I have.

I want to make sure timing is correct but without the detailed info on how to change it, I'm afraid I'd just mess it up.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
27,883
Re: What happens if timing is off?

My advice to you is leave it alone. It is running well, and has not burned a piston. To do it according to the book, you need a test prop, a professional test tank or put it in the lake, a timing light that will keep up with the high rpms, and the specs. A good example of if it ain't broke, don't fix it.
 

Cady8special

Seaman
Joined
Aug 24, 2011
Messages
64
Re: What happens if timing is off?

That might be the best advice of all. Obviously you wouldn't know for sure without seeing my boat run, but if it starts up no problem- idles no problem, and has no issues through all RPM Ranges, and gets up to 5500RPM's on a flat lake-- would it be safe to assume that my timing does not need an adjustment?
 

archcycle

Chief Petty Officer
Joined
Sep 21, 2009
Messages
635
Re: What happens if timing is off?

+1 on the don't touch. The best you can hope for is confirmation of what you already know, that it's set well, and worst case is you get tempted to fix something that's not broken :)
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: What happens if timing is off?

Screw up the timing and fry the motor!
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,814
Re: What happens if timing is off?

Ditto. Leave it alone !!
 
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