Calibrate Tach?

[Mr.Ladyfish]

I replaced my tach last week because the old one would not work below 1800 rpm. Faria replaced it at no charge. After installation WOT was about 300 to 400 rpm less than the old tach read. Idle also shows about 500 rpm compared to 850 rpm when the old tach worked. I called Faria and they asked me how I knew the old one was right. I explained that I didn't except that I didn't think the motor would keep running at 500 rpm. They told me how to calibrate the tach but said i needed a shop tach. Had a friend call his mechanic to see if we could borrow one. The mechanic told him it would have to be wired into the engine and was very complicated. Suggested we bring the boat in. I don't mind spending a few bucks to have it done but I don't know this guy and when we called him a couple of years ago about the check engine alarm going off on a new motor his response was "bring it in & we'll rebuild the carbs". Needless to say I don't trust him.<br />You guys got any suggestions? Has anyone calibrated their own tach?<br />Thanks for any help.

 

[Dhadley]

Re: Calibrate Tach?

The shop tach has one clip that goes over a spark plug wire like a timing light. (I guess it could be complicated if you didnt know what a spark plug wire was??)<br /><br />On the other hand I wouldnt loan out my shop tach either.<br /><br />As for the Faria, I've seen that before. They claim their tachs are + or - 5%. At 6000 thats a reading of from 5700 to 6300. Not real good especially if youre trying to set up a twin (or triple) engine deal. <br /><br />Since you posted here we assume you have an E/J motor. My suggestion would be to get an OE tach. To be honest they are some of the most accurate around. Especially the digital tach. Thats why you see so many OMC digitals on other motors.

 

[Mr.Ladyfish]

Re: Calibrate Tach?

Sorry, its a 2002 150 Johnson. I had planned on buying a Johnson tach but when they offered to replace it at no charge I figured what the heck. Get what you pay for I guess. I thought that the shop tach Faria was talking about sounded a lot simpler than what the mechanic told my friend. Don't think I'll be taking the boat to that guy.