Resistance Values for Delco Fuel Senders

The Dog House · Post by **The Dog House** » Sat Jun 09, 2012 10:05 pm

As I found out (the hard way), Trojans do not use standard American sending units. Replacing the oil pressure and water temperature sending units with American standard sending units will be relatively easy and inexpensive. The American standard sending unit for the fuel level is twice as expensive as a new gauge. Does anyone know the resistance values for the Delco fuel senders that I believe are in my 1971 F26? The gauges currently read 1/4 when they are full, which would correspond to 180 ohms (the same as the European standard). If European standard gauges will work with the Delco fuel senders, it will be much easier and cheaper to replace the gauges instead of the senders. Does anyone know if European (E = 10 ohms, F = 180 ohms) gauges will work with the Delco senders?

prowlersfish · Post by **prowlersfish** » Sun Jun 10, 2012 7:32 am

No , there are at least 7 different ranges of fuel senders ( that I have listed in my info ) a few common ones and some real odd ones , some that are backward of others . "euro" range senders are difrent then the old delco senders ( and delco had more then 1 range) ( 0-30 0-90 90-0 )
other gage ranges include 240-33 and 10-180 .( all ohms )

The only correct way is to get a sender that meets the specs of your gage(s) . And if you have duel gages ( upper and lower helm ) the sender must be for duel stations.

And don't blame trojan the delco set up was pretty standard at the time . Things change over time .

Big D · Post by **Big D** » Sun Jun 10, 2012 9:07 am

In my notes for Delco fuel senders, I see 0-90 ohms.

larryeddington · Post by **larryeddington** » Sun Jun 10, 2012 10:48 am

My tanks are out and I just checked the old Delco float type senders. They were half the current industry standard (33-240 ohm) the delco was 20-120 ohm.

My new tanks have the new ones so am changing gauges. It turned out I had not noticed not gages in Flybridge.

I talked with Moeller engineer regarding having double gauges. He said there have no double gauge senders and their recomendation is to use two senders in each tank. He further stated that if you were using dual gauges for a non safety related part of equipment such as lawnmower you can use two gauges on one sender. However moeller does not recommend that only two senders per tank.

I just went through this excercise last week. I will only have lower gauges.

ready123 · Post by **ready123** » Sun Jun 10, 2012 12:56 pm

larryeddington wrote:I will only have lower gauges.

Were it me I would have gauges only on the bridge... in 6 yrs I have only used the lower helm once for a journey

prowlersfish · Post by **prowlersfish** » Sun Jun 10, 2012 1:00 pm

ready123 wrote:
larryeddington wrote:I will only have lower gauges.
Were it me I would have gauges only on the bridge... in 6 yrs I have only used the lower helm once for a journey

Ready , he is only talking fuel gages , his F32 like my boat only came with them on the lower helm .

larryeddington · Post by **larryeddington** » Sun Jun 10, 2012 1:44 pm

Paul is correct trojan put all other gauges in both places but not fuel. Just ordered two new suns that match my new senders and will be in lower helm.

The Dog House · Post by **The Dog House** » Sun Jun 10, 2012 5:22 pm

larryeddington wrote:My tanks are out and I just checked the old Delso float type senders. They were half the current industry standard (33-240 ohm) the delco was 20-120 ohm.

This certainly is a mystery.

My American standard fuel gauges (E = 240 ohm and F = 33.5 ohm) decrease when I add fuel, so the senders I have are definitely not the Delco senders that are E = 120 ohm and F = 20 ohm. If that were the case, my gauges would increase when I added fuel with 1/2 on the gauge equal to E and F on the gauge equal to F. What year is your F28? I wonder if Delco changed the standard between 1971 (my boat's year) and the year your boat was made.

With my tanks full, my gauges are reading 1/4. 0.75 x 240 = 180, so the senders should be at 180 ohms. I'm wondering now if the senders have been replaced? There's always so many unknowns with an old boat.

Thank you for the information. If I ever get it figured out, I'll let you know.

ready123 · Post by **ready123** » Sun Jun 10, 2012 6:43 pm

prowlersfish wrote:
ready123 wrote:
larryeddington wrote:I will only have lower gauges.
Were it me I would have gauges only on the bridge... in 6 yrs I have only used the lower helm once for a journey
Ready , he is only talking fuel gages , his F32 like my boat only came with them on the lower helm .

I know that, what I'm saying if I were upgrading I would put the new one's up on the bridge and remove lower ones.
I have run out of gas on one tank because I did not see the gauge on a long trip....

larryeddington · Post by **larryeddington** » Sun Jun 10, 2012 10:10 pm

I can see that for sure, where I am in TX Long trips are pretty much non existant, but still something to watch.

ready123 · Post by **ready123** » Sun Jun 10, 2012 11:31 pm

larryeddington wrote:I can see that for sure, where I am in TX Long trips are pretty much non existant, but still something to watch.

All I'm saying is why would you not want them at the station you use most frequently? I agree moving the old one's may not be worth the effort.... but why not do it when upgrading the instrument is my feeling.

larryeddington · Post by **larryeddington** » Mon Jun 11, 2012 9:50 am

On thinking this out it would be possible to put a relay in the circuit to put the sending unit output to eigher helm selectively, in fact it could ba automated fairly easily or just manually by a toggle of a switch, Gonna think on this one a bit. I like all gauges where I am operating the vessel at as well.

prowlersfish · Post by **prowlersfish** » Mon Jun 11, 2012 12:06 pm

toggle switch ( keep it simple)