gas and temperature gauges

[Graham]

I'm replacing my temperature and gas gauges with new ISSPRO units.

I've found the temperature gauge and temperature sending unit on moyermarine.com. I have not been able to find the gas gauge and solenoid. Do they sell these?

I also see a breaker on my fuze box called "gas solenoid". I'm trying to understand why it has it's own spot on the panel? My gas gauge is not working.

Thanks,

[tenders]

Could "gas solenoid" have something to do with an old, or current, natural gas tank used for stove fuel?

Those have solenoids. I don't think A4s do, except for the starter, which would not be labeled "gas" nor be run to a breaker like you're describing.

Not sure if tanks for propane stoves have solenoids, I guess they could.

[Graham]

Could "gas solenoid" have something to do with an old, or current, natural gas tank used for stove fuel?

Those have solenoids. I don't think A4s do, except for the starter, which would not be labeled "gas" nor be run to a breaker like you're describing.

Not sure if tanks for propane stoves have solenoids, I guess they could.

That sounds possible. There is a switch and small LED light that comes on if I turn the propane on for the stove.

thanks!

[Graham]

Now I just need to find a new gas gauge for the boat.

[ndutton]

Graham,
Are you replacing the fuel gauge for appearance, function or both? If for function, there's no certainty the gauge is faulty and some troubleshooting is in order:

1. Is there 12V + and - to the gauge when the engine is running? If no, resolve and be certain + and - are on the correct gauge terminals.
2. If #1 is a yes, does shorting the gauge 'S' terminal briefly to ground peg the gauge needle to Full? If no, gauge is faulty.
3. If #2 is a yes does shorting the wire at the center of the tank sender briefly to ground (not the tank for this test) peg the gauge terminal to Full? If no, the wire between the gauge and the tank is faulty.
4. If #3 is a yes does shorting the wire at the center of the tank sender briefly to one of its six mounting screws peg the gauge terminal to Full? If no, the tank ground wire is faulty.
5. If #4 is a yes the tank sender is faulty.

If all the above is a yes and the gauge still does not work, is there gas in the tank?

[Graham]

Thanks ndutton,

I'm replacing the gauge because it does not work.

I'll perform these tests and report back.

Thanks for the help!

[joe_db]

http://www.ebay.com/itm/Fuel-Level-Gauge-240-33-Ohm-ISSPRO-R8690-/261769805204?hash=item3cf2b23d94:g:FMYAAOSwe-FU2SLh&vxp=mtr

http://www.chiefaircraft.com/iss-fg-01.html

Two fuel gauges for you, both use 240-33 ohm senders. This is the most common range for senders in the USA, but there are others.
There is about a 99% chance the "gas solenoid" switch relates to a propane or CNG stove and not the engine.

[tenders]

If your fuel gauge is bad I would suggest replacing both it and the sending unit in the tank. There's really no way one could be much better off than the other. Note that the (5?) holes mounting the sending unit in the tank look like they're arranged in a symmetric pattern, but they are not! It only goes in one way.

[Graham]

Thanks for the help everyone. I tested the gauges tonight (as ndutton suggested) and from what I can tell the gas and temperature gauges are are broken. I'll be ordering new gauges and sending units tomorrow.

I'll report back after I get them installed.

[Vermonstah]

Graham,
Are you replacing the fuel gauge for appearance, function or both? If for function, there's no certainty the gauge is faulty and some troubleshooting is in order:
...

If all the above is a yes and the gauge still does not work, is there gas in the tank?

Apologies to Graham for pig-backing onto his thread but very timely.
And shout out to Neil for such a fantastic checklist to follow.

I too have a temp gauge and a fuel gauge giving bad readings, since I have owned the boat. Fuel level is easy enough to visually confirm so my focus has been on getting good temp readings. Lacking any knowledge on how to troubleshoot the existing temp gauge, long ago I purchased the Moyer temp gauge and sending unit. But I have procrastinated installing it as I have limited access to the back of the gauges panel and there is a rat's nest of wires there. So I have instead opted for the hand held, temp reader that was highly recommended on this forum. But I was feeling ambitious last week and so installed the matching sending unit for the new temp gauge. That is my background info and here are (finally) my two questions:

1. what (if any) changes should I make to Neil's checklist above for testing temp gauge and sending unit?

2. should I re-install old sending unit before running thru checklist?

As always, thank you all for this forum!
Brian

[joe_db]

The sender and gauge work the same way, so the checklist should be good. American standard fuel, oil, and temperature are all 240-33 ohm senders

[JOHN COOKSON]

I too have a temp gauge and a fuel gauge giving bad readings,(?) since I have owned the boat.
As always, thank you all for this forum!
Brian

Are the gauges reading to high or to low? If there is resistance in the wiring sending unit->gauge the gauge will read to low.
To check let the wiring loose at the sending unit and gauge then attach a jumper wire to one end of the wire and lead it near the other end. Lay an ohm meter on the two ends. S\B zero ohms.

TRUE GRIT

[joe_db]

Another reason is mismatched senders. Each sender basically has a 33 ohms is full scale and 240 ohms is at the low end range. If a 100 PSI sender is hooked to an 80 PSI gauge, 80 will really be 100 and 40 will really be 50. Likewise is a 240 degree gauge is on a 320 degree sender will be off or vice versa.

Are the gauges reading to high or to low? If there is resistance in the wiring sending unit->gauge the gauge will read to low.
To check let the wiring loose at the sending unit and gauge then attach a jumper wire to one end of the wire and lead it near the other end. Lay an ohm meter on the two ends. S\B zero ohms.

TRUE GRIT

[Vermonstah]

Are the gauges reading to high or to low?

TRUE GRIT

The temp gauge does not depict a reading at all, and my fuel gauge records too low. Fuel = 1/4 tank independent of actual fuel levels.

To check let the wiring loose at the sending unit and gauge then attach a jumper wire to one end of the wire and lead it near the other end. Lay an ohm meter on the two ends. S\B zero ohms.

TRUE GRIT

I will perform this diagnostic test and report back.

Thanks again!

[Vermonstah]

Another reason is mismatched senders.

I cannot confirm that the existing gauge / sending unit pairs are a match. And I have learned from this forum that proper replacement requires the matching pair. And I have a new temp gauge / sending unit from Moyer, though I have procrastinated on attempting the install. But now that I have safely removed the old sending unit from the head, it is time that I get this sorted out, starting with the temp gauge.

Thanks for the diagnostic tips.