How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Michael Your Own Question
Michael, Master Mechanic
Category: Boat
Satisfied Customers: 257
Experience:  Over 25 years experience working on everything from PWC's to Mega Yachts
Type Your Boat Question Here...
Michael is online now
A new question is answered every 9 seconds

My tach has stopped working. How do I check to see if it is

This answer was rated:

My tach has stopped working. How do I check to see if it is the tach or the sending unit? My gas guage has stopped worked. I have checked the guage and it seems to be operative.   I need to know the location of the sender unit and how to get access.

Hurricane Boat 2003 23'7" Sundeck or Fundeck
Hi, thanks for your question, it sounds to me like your tachometer is bad but you can check it the same way as the fuel gage.. find the sending wire to the tach(should be brown or purple) and ground it while looking at the tach... same thing, if it pegs the tach then the gage is good and you'll need to trace the wire back and make sure it's got continuity.
As for the fuel gage, you have a bad sending unit or bad connection/ground at the sending unit. These are usually located on top of the tank near the fuel pick up and vent lines... it will be approx. a 2" diameter flange about six screws mounting it to the tank. should be the only component on the top of the tank with two wires leading to it. Some boats have an inspection plate in the floor to access this. Check the connections and if they look good you should try grounding the sending wire(center wire) from here to assure the wire is good leading to the gage. If the connections and the wire are good then just replace the sending unit and you're done.
If you still need help finding the sending unit, then reply back and post the make, model, and year of the boat and I will tell you how to locate it.
I hope this helps, let me know if you need further assistance and I will be happy to help you. If you feel my answer has helped, please click the accept button so that I may be credited for my time.

Best regards,

Michael and other Boat Specialists are ready to help you
Customer: replied 7 years ago.
2003 hurricane 23'7" Sundeck or Fundeck. I cannot find any access that leads me to the fuel tank.
Ok, I'm not sure which floor plan you have but most Fundeck's have a bench type seat in the rear. If you look under the seat you should find an inspection cover to access the fuel tank.
Also, as for the tach issue, I forgot to mention that the problem could also be the voltage rectifier. You can put a volt meter on your battery and get a static reading(with engine off) then start the engine and see if the voltage increases. If it remains the same, it's not charging and you may have a bad rectifier.

Let me know what you come up with and if you need further assistance.

Customer: replied 7 years ago.

Thank you. I found the sender to be bad. The in-dash depth finder has stopped working. There are 3 wires coming out the back. One is power, one to the transducer. What does the 3rd wire go to?


Do I need to go back to the dealer for the sender or can it be purchased at a parts store?

I'm glad you were able to find the sending unit and test it! The third wire on the depth gage is either ground or an instrument light. if the gage has a light bulb in it, it's for that otherwise it's a ground.
As for the fuel sending unit, you could buy from a marine parts store such as West Marine or Boat US etc. (not sure where you're located).
Be sure and take your old one with you because you will most likely be matching it up to a universal kit.. just make sure it has the proper bolt pattern on the mounting flange and that it will give you the proper depth capability.
Thank you for the accept and let me know if you need further assistance. If you find my answers helpful please consider positive feedback and bonuses are much appreciated.

Best Regards,


Edited by Michael on 6/21/2010 at 4:51 AM EST