Using vacuum signal to set idle mixture?

[W_Guy]

I've read Joe's excellent procedure for setting idle mixture in the top secret thread but I was curious whether the two throat carb on my '58 Four Fifty has a manifold vacuum take-off. I've always set the idle mixture on my cars by using a vacuum gauge to achieve the highest steady reading. IS this method possible on my motor/carb?
Verne

 

[tashasdaddy]

Re: Using vacuum signal to set idle mixture?

your car is a 4 stroke, you motor is a 2 stroke.

 

[a70eliminator]

Re: Using vacuum signal to set idle mixture?

I've adjusted air/fuel mixture ratio using both a vacuum guage by ear and electronics and what I've learned is that if to effect the ratio enough to drop the vacuum you'll hear it as well, ears are my most valuable tool.
I have not come across any 2 cylcle outboard that has a ported vacuum tap off the mainfold, nor have I ever monitored vacuum on a 2 stoke, my experience has been with 4 stroke motors. I tune the idle on my 2 strokes by ear.

 

[W_Guy]

Re: Using vacuum signal to set idle mixture?

Thanks. I didn't know if it was possible on a 2 stroke or not....

 

[billy4hp]

Re: Using vacuum signal to set idle mixture?

Thanks. I didn't know if it was possible on a 2 stroke or not....

I have tuned a few high performance two strokes and had a vac. guage hooked up to obtain reference readings...

My experience has been best vac. reading is a lean setting. Remember the fuel is also the lubrication with your two stroke engine...

JMHO...

 

[W_Guy]

Re: Using vacuum signal to set idle mixture?

Thanks. I'm content with using the "ear method". I just thought I'd ask. I can't wait to get it on the water this year and tweak it a bit.

 

[ENSIGN]

Re: Using vacuum signal to set idle mixture?

I was told in mercury ob school not to adjust the carbs for a real smooth idle as this will cause the engine to run to lean.