High rpm's at idle

[matt194]

My tach stopped working so I bought a used one off ebay. It is a Suzuki tach. My motor is a 1979 Evinrude 115hp. When I run the motor in the driveway I get a reading of about 1600 rpm's. I know it should be around 1000rpm's in the driveway. I tried moving the throttle lever on the motor to lower the rpm's but the motor would start to die at about 1200rpm's. How do I lower the rpms without the motor dying?

Thanks,

Matt

 

[HighTrim]

Re: High rpm's at idle

Tachs read off the alternating pulses from the stator. Any of the leads from the stator charging portion can be used for the signal. The designated tach signal wire is merely attached to one of those. Tachs have rotary switches on the back that set it to different numbers of coils in the charging circuit, times two because there is a positive and negative pulse for each coil for each cycle. Tachs measure pulses. That being said, you need a tach that has the setting that you need designated on the rotary switch.

What setting do you have the rotary switch on?

 

[matt194]

Re: High rpm's at idle

Sorry I don't know what or where the rotary switch is. I have the tach set on 8p. Is the rotary switch the thing on the tach?

 

[HighTrim]

Re: High rpm's at idle

That is where your problem lies. Change it to 6p

 

[matt194]

Re: High rpm's at idle

I have a 4 cylinders with 4 coils so shouldn't it be 8p.

 

[matt194]

Re: High rpm's at idle

I went and bought a photo sensor tachometer to verify the tach on my boat is working. The tach on my boat is working great. Now how do I lower the rpms without the engine dying. When I say the engine dies when I try to lower the rpms, I am saying i'm moving the spark advance lever back. I have a manual but I don't know which procedure to do. Should I be doing the throttle pickup point adjustment or the throttle and timer synch? I don't know if any of these are correct, please point me to the procedure I need to do to correct this problem.

Thanks