Newbie - reserve gas tank

[L&L]

hi all...
we just purchased a 1974 Trojan 36ft -
has 4 fuel intakes on the side decks.
while seated in the captain's chair with all the gauges in front of me, I see two for FUEL.

there is also two pull handles - each labeled RESERVE FUEL - below the gauges

so yesterday we took the boat out.
the fuel gauge on the right indicated that we had 1/4 tank left when we started - when I pulled the reserve tank handle on the right side, the gauge went to empty....press the handle back in, it went up to 1/4 tank.

so I'm assuming that the right side tanks had 1/4 fuel in them - period - no reserve....

the fuel gauge on the left indicated that it was basically empty - but when I pulled the handle for the left side gauge reserve fuel, the gauge went to full....so I'm thinkin ok, well, I may be out in the primary tank but I do have backup fuel - so I left the left side handle pulled out so they gauge showed FULL

so, about an hour into our journey while headed back to dock, we ran out of gas - engine stopped cold - right side gauge on EMPTY - so yeah ok, it's empty - I get that....

Yes I am a newbie....I have the owners manual....it says I have reserve tanks but doesn't mention how they operate....obviously my assumptions on how they operate are wrong....

My question is - why didn't the reserve tank activate and keep me going??

What did I do wrong??
Do I have to manually do something to make the boat run off the reserve tanks??

[prowlersfish]

Are you sure the pull handles are not switches ? There should be valves to change over tanks . Even if the handles are for changing over ( not oem ? ) if they were empty that would not help

Photos ?

[gitchisum]

This is just a guess, but from what you are describing, you had a 1/4 tank on starboard forward tank, and an empty aft tank, then an empty forward port tank and an aft tank that read full. you should have~75 gallons in port tank and the starboard tank had about 20 gallons in it.

If the guage and sending units were operating normally, and you truely had 75 gallons in it, you may have a problem with getting fuel out of that tank. ( anti syphon valve, pickup tube, filters lines, etc)

I am chasing that issue on my F-32, where I put 50 gallons in my port aft tank and I am not pulling fuel. ( I have manual valves with a cross over)

If you did not put the full tank in, verify it really has a full load, then go from there. If not, you could have an issue with guage or sending unit.

Based on an hour of run time, I'd say you started with one tank @ 1/4, and did run out of gas. My guess is what someone has labelled "reserve" is actually aft and forward tank is main. ( or vice versa)

If the switches are like Paul said, they will swap sending units for the guages, but you still manually need to turn the tank on. You could have had a full tank that was simply not turned on to feed the engines.

More information and pictures will help.

[L&L]

I appreciate both comments very much.
I will try to take pics tomorrow and post on Wednesday....of the tank fill areas and the gauges....
What you both are saying makes sense - I'm a novice but learning....