Thread:

Gauge help

Who is in the know when it comes to gauge sets? I would like to upgrade my gauges and would like some help getting going in the right derection. All the sets I see only have 5 gauges. I need 10. I would like them all to match. What is the easeist? Do you have to buy adapters or is that just for lavorsi? Right now I have black Faria that sit behind my dash panel. Not very appealing. Thanks

Thanks, I will try and get a hold him.

You don’t have to buy gauges in a set. You can buy all individually form most sources. The standard gauges for most would be tachometer, oil pressure, water temperature, trim gauge, fuel level and a voltmeter. Someboats use a mechanical trim indicator with a cable attached to the drive at one end and to a sliding indicator pin at the other. The other gauges most people add to the standard would be an oil temperature, water pressure, fuel pressure, pyrometer (exhaust gas temperature), manifold pressure in the form of vacuum or boost or a combination vacuum-boost, drive temperature, and speedometer.

Most electric gauges use some sort of sender with the exception of the tachometer and pyrometer (pyrometer use special thermocouples). It should be noted that all gauges do not use the same sender. Most for automotive use, such as fuel level are different than those used for marine. The sender is nothing more than an inline variable resister. The gauge also has a built in resister. In electronics the voltage drop across all resisters is equal to the source voltage. In the 12 volt two resister gauge circuit the voltage drop across both gauge and sender would be 12 volts. As the variable resister changes the voltage drop changes; this voltage drop cause the drop across the gauge to change because the drop across the sender and that of the gauge has to equal 12 volt. ALL gauges that use variable resistor sender are nothing more than voltmeters measuring the voltage drop across it. Technically most all marine gauges start out as voltmeters and the face is change to represent the different functions. Most marine electric gauges use senders with a 240-33 ohm range. Most electric gauges are more of an indicator and not reliable if you want exact or correct readings. If the electric gauge is showing a reading much lower or higher than normal than you could assume a problem exist.

Gauges that do not use senders, outside of tachometers, are mechanical. Mechanical gauges are direct read, meaning they have something connected direct to the source being monitored. Pressure gauges are most common to see mechanical connections. Most just require a simple hose between the gauge and source. Temperature gauges are a bit more complex requiring some sort of capillary tube connected to the source. The tubes are usually made of copper and very small in diameter. The tubes are gas filled and cannot be cut or extended so they have to be purchased in the appropriate lengths. Fuel pressure gauges with a single hose to the dash should be avoided. A rupture in the hose could be very dangerous. If you must use a mechanical fuel pressure then purchase an isolator. Isolators can be used inline but I don’t think any are Ccoast Guard approved for marine fuel systems. One more thing to keep in mind when installing mechanical pressure gauges; some people use very large ID hoses. For most gauges the hose is filled mostly if not all with air. Because air is a gas it can compress. The large ID hose has a lot air space that can compress and requires a long time to happen. This causes the pressure gauge to react slowly and never read the correct pressure; best to use the smallest ID line. You can always run the smaller line inside another with a larger ID for protection.

The last is gauge sizes. Most tachometer and speedometers are 3-3/8” diameter which refers to the mounting hole requirement. Smaller gauges have a 2-1/16” requirement. The monster gauges require 5” and 2-5/8”.The internal working between the small gauge and the larger gauge are the same.The bigger gauges benefits from a larger dial that is easier to read.

You first need to determine what size your existing gauges holes are. If you want to go with larger you need to make sure if you can enlarge the holes and still have room to install the bigger gauges. Next would be to make a list of the gauges you need and if you want electric or mechanical. Because you have Faria installed presently I would guess you have the 3-3/8” tach/speedo and 2-1/16” size for all smaller gauges and all would be electric with the generic 240/33 ohm senders.

Now thats somebody who knows gauges. Thanks for the information. That is way more than I thought I would get for information. This does help. I was thinking everything was just a plug and play but this information and talking to brian yesterday shows me I have some home work before I order. Thanks again.

one of your old gauges doesn't happen to be a clock does it?

Yes one of them is a clock. I think someone broke it intentionally so they couldn’t tell when to go to shore. Pretty unattractive gauge set up. Won’t be for long though.

Those are the ones I have priced out. I think they will look good with blue bezels. I am working on the dash pannel itself before I order. I am trying to figure out if I want to have the dash pannel painted, wrapped with vinyle to look like carbon fiber or just have a carbon fiber coating added to it. Any other ideas?

Lots of complete sets on E-bay. Very cheap.

Personally, I would get a piece of anodized aluminum and make a plate to mount the gauges and bezels to the outside and mount it where you have it...or take the piece you have now and have it powdercoated.

I was thinking the same thing on the powder coating. The anodized piece sounds cool too and way cheaper. If i could find a dealer for carbon fiber I could have it cut to place on the outside too. Thanks for the tip on ebay. Cant get there from here at work i will have to check it out when I get home.