fuel tank sender

The fuel guage on my boat (2000 Monterey 240) always reads 3/4 to 7/8 full regardless of actual fuel level. Gauge checked OK by grounding. Pulled fuel sender and it moved freely but moving donut up and down shaft doesn't change gauge. Assuming I need a new sender, do I need to get another donut type sender or will an arm type sender work just as well?

Some senders are listed for a range of tank depths- how do I make the sender read correctly with my tank?

Thanks

Re: fuel tank sender

Assuming I need a new sender, do I need to get another donut type sender or will an arm type sender work just as well?

Some senders are listed for a range of tank depths- how do I make the sender read correctly with my tank?

Click to expand...

Ayuh,...... You need a Sender that matches your gauge's Ohm reading abilities...
Either design, Should work...
The Depth,..?? Measure it.......

Re: fuel tank sender

The sender in my tank is 13" from flange to end of the aluminum tube. Using an ohmeter, the resistance is 30 ohms when donut is at top of tube then increases to approximately 60 ohms 1/4 down the tube but then stays at 60 ohms regardless of the donut position at less than 3/4 full. That would seem to explain why the gauge never reads less than 3/4 full.

The sender is not marked in any way. How can I determine what voltage range is required for my gauge. I am confident that 30 ohms is full but can't say for certain about empty resistance.

Concerning the universal lever type gauges- some are listed as compatible with a range of tank depths. How is the sender adjusted to compensate for the different tank depths?

Re: fuel tank sender

30-260 ohm I think is the US standard then theres the euro version. The arm type tank senders are adjustable by clipping the arm and slightly bending it. They are affected by the boats running position and sloshing. I'd get the donut style for the extra $20.00. They arnt as mechanical, there a little more accurate and seem to last longer especially if your boat is used off shore.

Re: fuel tank sender

30-240 ohms is the normal spec for U.S. fuel senders and gauges. You can use a swing arm type if you wish. Some are adjustable for tank depth. Some need to have the vertical support shaft cut to a specific length for the tank.

Re: fuel tank sender

I just saw a new issue of "Boating" had a comparison of sending units. The compared 3 types, the Arm, Verticle, and Ultrasonic. The 'arm' style bounces in the tank as your boat bounces on the water..I have an arm style & it's about useless. I'd stick to a vertical as you had or upgrade to an ultrasonic..
Check out the article..
Fuel-Monitoring Systems By Joe Friedman Article

Re: fuel tank sender

I agree with the article, I use a NORTHSTAR fuel flow gauge and have found it to be accurate and then you also know how much fuel are burning per hour and what is left in the tank. It does not work off the motor fuel injector theory.
I just had a new tank installed in my boat and it has a gauge/sender for the tank and seems to do OK as long as you are not bouncing around all the time. I have no idea what brand or type of sender they installed.

Re: fuel tank sender

That's a pretty cool article. I have a simple rectangular gas tank, 10" deep on a small 20' MFG. I use the Teleflex swing arm type sender and gauge. I cut the sender arm to I believe almost 9.75" but will take it out to verify after reading the article. My tank is 44 gallons and this weekend I was running around with a gauge that stopped registering fuel from the sloshing for quite a while. I guess my pickup is a bit lower than 1" above the bottom of the tank thankfully. I'm trying to figure out how much gas I use. Any guess on what a 200 hp 1985 Yamaha outboard should burn roughly? At first I thought I was burning about 5 gph but a friend told me that would be amazingly fantastic. I probably burn closer to double that though. On July 4th I had about half a tank and ran the motor for a little over two and a half hours but I also did some idling and the LI Sound was rough so I had less than perfect sea conditions to run in. This weekend it was basically empty. I'd hate to think this outboard uses well over 10 gph.

Re: fuel tank sender

Thanks for the replies. I bought a new sender from a company in FL (not sure if using vendor names is allowed) - approx $40 including shipping for a high quality stainless steel sender. I like it when fixes are easier/cheaper than expected.

Re: fuel tank sender

Big Keepers Big Keepers is offline
Petty Officer 1st Class
Get use to it, that motor easily burns 12 gph @ 4200pm.