tach and fuel guage 89 merc.

[cyote]

New to this site,seems like a good place to retrieve info. Yesterday I decided to run my boat and my tach and fuel guage are not working I tested the fuel guage and it works so I am leaning towards a loose ground and was wondering if anyone knew what area to look in. Boat is a 1989 mastercraft with a 1989 175 black max. Any help will be appreciated.

 

[cyote]

Re: tach and fuel gauge 89 merc.

Re: tach and fuel gauge 89 merc.

ok worked on boat tonight and figured out that the sending unit for fuel tank was a lil corroded cleaned it up and fuel gauge works not tach is still not working tested the regulator on AC current at yellow wires going out and the AC current was 18 to 19 which I am understanding indicates a bad regulator just looking now for a second opinion before buying a new regulator Also if this is the prob where is a good place to buy a regulator.

 

[Texasmark]

Re: tach and fuel guage 89 merc.

Speaking from a '95 150's experience:

This engine has a 40 amp regular system composed of 2 20 amp modules. Each module has a grey wire for tach operation. Improper tach operation caused by a bad regulator module can be corrected by connecting the tach to the other module. Also you could have dirty power/ground wiring to the tach.

Also the tach could be bad which was the problem with son's boat....Merc dealer had one for $88; matched the other instruments.

During operation at roughly 3000 rpm's the battery voltage should be in the 14+ volts area (battery with a reasonable charge on it at the time). Problem is, you don't know if both modules are supplying current unless you disconnect them separately and run the engine.

One way is to unplug and tape up (to prevent any shorting out) the yellow input wires to the module (one set at a time) and see if you get charging voltage to the battery.

Mark

 

[cyote]

Re: tach and fuel guage 89 merc.

Thank you Texas Mark for the response but my system only has one regulator and I am also lucky enough to have probably the only one that cost 550 dollars which I went ahead and ordered am hoping this is my prob being they will not take back elec parts. I will chime in once it comes in and I get to try it and if its not it I will also post what it was maybe it could help someone else in the future Thanks Again

 

[Texasmark]

Re: tach and fuel guage 89 merc.

Good luck. Geez that's a lot of moola for a few diodes and a transistor.

Mark

 

[wire2]

Re: tach and fuel guage 89 merc.

Thank you Texas Mark for the response but my system only has one regulator and I am also lucky enough to have probably the only one that cost 550 dollars which I went ahead and ordered am hoping this is my prob being they will not take back elec parts. I will chime in once it comes in and I get to try it and if its not it I will also post what it was maybe it could help someone else in the future Thanks Again

$550? OUCH!!!
I'd consider a new 1 wire marine alternator with built in regulator from fleabay for ~$65.

 

[cyote]

Re: tach and fuel guage 89 merc.

ok good news the regulator did work the only prob now is it leaks around the head b/c they do not offer the oring for it anymore so I put some rtv sealent on it and tommorrow we will see if she still leaks but I am glad that was the prob thanks for everyones help

 

[Texasmark]

Re: tach and fuel guage 89 merc.

What leaks around the head?

 

[cyote]

Re: tach and fuel guage 89 merc.

water this regulator has a box that go inside the head to sense water temp from what I understand but it does not got to the temp guage it must control something else.