New gauges

larglo · Post by **larglo** » Thu Nov 05, 2009 12:55 pm

Hi all,

I have 3 gaudes not woking, temp., fuel, and oil. pressure. I plan to get new sending units for the temp and oil, and I can see that the fuel gauge doesn't even have a wire going to the sending unit.

I would like to replace my gauges so they would all match. But I was wondering if the new gauges have as many connections as the ones I have now?

All gauges have at least 4 posts and I think one has 5 post to connect wires to.

Is it possible to rewire the gauges to match any difference from the old gauges.

I have looked at the color of the wire, of each gage, behind the consol panel. But when I look at the wire color at the gauge connections, they are different, making it hard to follow the routeing.

What I'm thinging, is buying new gauges and rewire the whole mess?

I thank you for any suggestions?

Larry

PS, my boat is a 1980 F25 HT

prowlersfish · Post by **prowlersfish** » Thu Nov 05, 2009 6:34 pm

Make sure if you change the gauge or gauges that the sender are made for the gauge you use or they could be off . If useing VDO gauges use VDO senders tempo gages use tempo senders etc. you should be able to use the wiring thats there

Danny Bailey · Post by **Danny Bailey** » Fri Nov 06, 2009 9:00 am

http://www.egauges.com/vdo_mult.asp?Typ ... on&Units=E

This website may help you

larglo · Post by **larglo** » Fri Nov 06, 2009 11:38 am

I have learned a great deal about gauges from your replies, and I thank you.

The VDO web site gave me detailed instructions about installing gauges etc. It seems as though the wire coming from the sending unit is always connected to the post labeled "S".

I do have one other question though. My F25 most likely has the original gas tank in it, 50 gal., which is metal. To order a new gauge I need to know the sending units OHM, output range.
Does anyone know what that would be? If I had to order a new sender, they have several listed, so any help in this area, would be most helpful also.

Sorry. one more thing,,,,the tread sizes for the water sender and oil pressure sender, such as 1/8" NPT, 1/2" NPT, etc. what would they be on a Chyslar 318 engine? Or how would I check to see what they are?

Thanks very much for you help.

Larry

larglo · Post by **larglo** » Fri Nov 06, 2009 11:57 am

Danny,

I just noticed that the web site you referred me to, are automtive gauges? Will it make a difference from marine gauges?

Larry

Paul · Post by **Paul** » Fri Nov 06, 2009 12:08 pm

Hi Larry,

Are you sure that the sending unit in your fuel tank is working properly. If your going to replace the gauges and sending units on the engine, you might consider installing a new sender in the fuel tank as well. This way you can purchase the gauge and the sender as a match set. The senders are not very expensive.

Hope this helps.

randyp · Post by **randyp** » Fri Nov 06, 2009 2:47 pm

I agree with Paul. But, please take a look at the tank while you're at it. Those stock galvanized metal tanks have had a nasty way of rusting on the inside due to years of condensation, etc. If you're going to go the route of new gauges and senders you might want to check out the cost of replacing the tank with a poly one. I did on the Blue Heron, changing out from the stock 75 gallon metal tank to a new 50 gallon poly tank with new gauge and sender. The gauge matches the originals on the instrument cluster, except I forgot to put the chrome trim ring back on the new gauge, and mounted the stock black plastic one on it. That was 9 years ago......one of these days I'll change that trim ring.

larglo · Post by **larglo** » Fri Nov 06, 2009 3:18 pm

Paul, Randy,

Right now there is no wire going to the sending unit. I will try to connect a wire to the sending post and then to the post on the back of the gage, to see it I get any reading.
I haven't the cash now to replace the tank, but it is on list to do, even if I get the gauge to work.
Thanks,

Larry

Danny Bailey · Post by **Danny Bailey** » Fri Nov 06, 2009 8:17 pm

http://www.egauges.com/vdo_marM.asp
Try this one Larry. It has the marine VDO guages. For figuring out the thread sizes I use a picture pipe thread gauge in a McMaster Carr catalog. You could go to Home Depot and buy pipe plugs 1/8, 1/4, 3/8 and see which one fits your engine. I'll bet its going to be either 1/8 or 1/4.