Full ign. advance on Evinrude Big Four?

[eltoquad]

I’m looking to find out what the guys running the Evinrude Big Four use as the full advance setting while running? The Big Fours have an adjustable stop that once motor starts you can push timing lever to this stop so that your timing is the same every time you run it wide open. Also, would it make a difference if your motor is dead stock or if it’s been modified such as raised compression, altered ports or opening up of intake port in crank case etc. I’d like the timing to be listed by thousands BTDC but in degrees BTDC would also be OK. Thanks, Tom

[RICHARD A. WHITE]

On the 3 Big Fours I have been out with it seems none of them like full advance….
Mine has not been started …………..yet

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[Pete]

Do you know the factory BTDC value for a stocker to start from. If mods done like compression increase, ports raised, etc and fuel octane and type and oil mix all make a difference. The way I adjust timing on my race engines is pick a start value (like stock) take a run and record speed and rpm, kick it up a small amount and run it and get results. Keep going until speed and rpm drop. To do that I make runs long enough like 1/2 mile so the engine gets heat soak which effects advance needed. Need to be careful with advance piston holes could result. 2 cycles like less advance at top speed than more, more generally increases lower end power and acceleration. How you use the boat and motor matters.

[eltoquad]

I don’t know factory stock timing. They come with a stop mounted to cylinder bolt which depending on looseness of mounting hole, bend in the stop etc. could vary a long ways on a stock motor.

[Pete]

quote eltoquad:

I don’t know factory stock timing. They come with a stop mounted to cylinder bolt which depending on looseness of mounting hole, bend in the stop etc. could vary a long ways on a stock motor.

That is not good. Need to get setting from people who have experience with that engine and that is not me.

[garry-in-michigan]

I never saw any figures, they depended on the magneto stop. (I cannot find it in the parts book, but i have seen it on the motor.) Dad had a tool from engineering that screwed into a spark plug hole. With the piston at Top Dead Center it screwed it until it touched the plunger in the center of the tool. Then the flywheel was turned counter clockwise and the plunger was pushed in. the flywheel was then turned clockwise until a line on the plunger became visible. The stop was then held against the magneto plate and the bolts holding the stop tightened. 😕

[Author]

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