Tach issue j130vxsss, cuts out at low rpm in gear comes back when increase throttle.

[Shorebum]

My tach is not bumping around but seems to have a problem at RPMs below 1000. When in the water out of gear holds right around 1000 rpm but when I put in gear it drops sometimes to zero, sometimes two hundred sometimes 600.... Once I increase throttle all good. At wot I am getting a reading of 5500 to 5600 on a twenty foot boat with 15x17 prop. Checked gray wire at wiring terminal block and all looks good. Anything internally in tach that could be impeding signal? Thoughts?
BTW had to replace stator last year and test of charging system at battery voltage was 14v after replacement. Did not do anything with rectifier thinking voltage output looked correct.
Thanks in advance

 

[HighTrim]

Re: Tach issue j130vxsss, cuts out at low rpm in gear comes back when increase throt

I would definately start by testing the rectifier. Don't run the motor until you do.

 

[Shorebum]

Re: Tach issue j130vxsss, cuts out at low rpm in gear comes back when increase throt

Was afraid of that. Had a situation where positive wire on starter got loose last year. Could that fry a rectifier?

 

[HighTrim]

Re: Tach issue j130vxsss, cuts out at low rpm in gear comes back when increase throt

You would be surprised what can fry the rectifier.

Mainly cross polarization. Run the quick test. Let us know if you need help with it.

 

[Shorebum]

Re: Tach issue j130vxsss, cuts out at low rpm in gear comes back when increase throt

Not sure what the quick test is. Where would I find it in the forum? With boat secured to trailer and in the water. I was going to start the motor on a good battery then switch my battery selector to all (drain a second battery down to about 11 volts) and take an amp reading on the red wire coming from the rectifier to the starter solenoid. Run RPMs up to about 3000 and take a reading, hopefully will see around 9 amps and going down as batteries take charge. Is there an easier way for the backyard guy?

 

[HighTrim]

Re: Tach issue j130vxsss, cuts out at low rpm in gear comes back when increase throt

The test is in the FAQs. Have a peek there.

 

[Shorebum]

Re: Tach issue j130vxsss, cuts out at low rpm in gear comes back when increase throt

Thanks, HighTrim. Found it. Basically just take the gray wire (Tach side) and jump it directly to stator, taking the regulator/rectifier out of the middle. I am away from my boat and will not be able to get back to it for a couple of weeks. Once done will dig up this post and update on findings. Thanks for the information.