1988 340 Sundancer fuel gauges not working

[Ka1oxd]

During the sea trial on my new boat, the fuel tank gauges were not working. They put about 20 gals in each tank, but they were reading empty. I have contacted Sea Ray for the schematics, so now I have at least the color of the wires and how they are run.

I am thinking since both gauges are not working that there must be a common ground that may not be working correctly.

Is there an access panel to where the sending units are n the tanks?

Has anyone else run into this problem? Is there an inline fuse somewhere that I cannot see on the schematics?

Any thoughts?

 

[electricaldoctor]

During the sea trial on my new boat, the fuel tank gauges were not working. They put about 20 gals in each tank, but they were reading empty. I have contacted Sea Ray for the schematics, so now I have at least the color of the wires and how they are run.

I am thinking since both gauges are not working that there must be a common ground that may not be working correctly.

Is there an access panel to where the sending units are n the tanks?

Has anyone else run into this problem? Is there an inline fuse somewhere that I cannot see on the schematics?

Any thoughts?

Ground and/or a fuse ... two excellent places to start. Highly unlikely that two gagues and/or sending units would be fried at the same time. I would go to the tanks only as a last resort. If you have the schematic, you s/b able to check for 12 volts + quite easily. Keep us posted. :thumbsup:

 

[Ka1oxd]

Would they be using the bonding system as ground between the tanks? I was just looking over the docs and wondering if that is where the problem is. The last owner had the starboard stuff box done. On the 340 SD you have to remove the exhaust pipes and squeeze into the area. Could be a real easy way to pull a wire. Will need to look.

 

[fwebster]

There is an easier way............

Ground the center wire on the sending unit to one of its mounting screws while someone watches the gauges. If you get a full deflection past the full mark, the problem is the sending unit in t he fuel tank. If the gauge doesn't move, then the problem is the gauge in the panel. There are no other components in the gauge circuit so if all the connections are tight, that will diagnose the problem.

On a boat this age, the chances are ivory soap percentages sure that the sending units are bad.

 

[giff1]

There are wire posts on top of the sending unit located on top of the fuel tanks. First, I would disconnect the wires and clean any corrosion at the tanks and the gauges. I have read in a manuel for 340s that 20 gallons of fuel will aways be unuseable in each tank,so if the tanks only have 20 gallons in them, the gauges may not be able to read it. Add more gas. Second,you could replace the gauges,Teleflex fits. Lastly, It could be the sending units in the tanks. I've heard E10 gas is playing hell with the sending unit floats.

 

[lucknow]

Would they be using the bonding system as ground between the tanks? I was just looking over the docs and wondering if that is where the problem is. The last owner had the starboard stuff box done. On the 340 SD you have to remove the exhaust pipes and squeeze into the area. Could be a real easy way to pull a wire. Will need to look.

Very unlikely, I agree with Frank. Follow his instructions, Most likely 1 sender failed, po used boat with one sending unit reading until the second one failed. I had the same issue when purchasing my 89 340. I would be surprised if your problem is not the sending units. Sending units are cheap and easy install.
Good Luck
Kevin

 

[flarepoman]

On mine 89 sundancer each side fuel gauge comes on W/ the Key-switch on the dash. Try the 12V test light trick and see if you have a little light comming from the sending unit on the top of the tank. if not most likely it is like said before a ground issue. Easy fix once you find it.

Rick

 

[Ka1oxd]

Thanks all, this has given me a lot tot test and makes life easier. I am so anxious for this boating season to start with a new boat. Today I am replacing the cutless bearing on the starboard side. I bought the strupro puller so I do not have to pull the shaft and the bearing came in Friday.

 

[rondds]

James
I'd like to hear more abt your cutlass bearing job. Got any photos of that? Not familiar with the strutpro puller. THANKS!

 

[Ka1oxd]

Rondds, I will send you some pictures this weekend when I push the new cutlass in. I ordered the strupro puller and it took about 1/2 hour to push out the cutless. The problem was I ordered the cutless based on the information in the manual for the boat. The problem was the sea ray manual stated the bearing was 1 1/4" ID by 1 3/4 OD, by 5". In reality, it was a 1 1/4 by 1 1/2 by 5. So if the snow stops this weekend, I now have the right cutless and will push it back in.

It worked well and was worth the $375 for the tool and the shipping. That is about what it would have cost me to have it done around here. Now I can do it anytime I have the boat out of the water. Would I recommend it to someone else, you bet I would. I did not have to pull the shaft, only the prop. quick and easy.

 

[osd9]

I'd bet you could rent that tool out for $50 a shot, and let the renter pay the shipping back and forth, and you could get your money back real quick.....good deal for you and the renter.....just saying!!!!

 

[BonBini]

Don't condemn this to be a failure of sort just yet. My 88 with it's 100 gal tank acted very similar when I sea trialed. I bought the boat knowing the fuel gauge had a problem. As it turned out; the gauge read full to empty with only 1/2 the fuel consumed. This drove me nuts. I pulled the sending unit and found it to be totally adjustable. I recalibrated it to read full to empty with 80 gal consumed, this gave me a 20 gal reserve.

These vintage analog gauges are nothing more than a volt gauge. +12vdc to one side and a variable ground to the other. The sending unit itselfs is just a rheostat.

To trouble shoot the circuit:
1) simply take your trusty 12v test light and test the +12v side of gauge, if ok...
2) then neg side, the gauge should partialy sweep and dimly light the test light as the circuit is complete, if ok...
3) then the signal wire at the sending unit, the gauge should partialy sweep and dimly light the test light as the circuit is complete, if ok...
4) then use your test light in series from a good ground to the sending units grounded body. A dim light and gauge sweep will indicate a bad ground. No light will indicate a open circuit most likely with in the sending unit.

note: These old Sea Rays are full of crimp style connectors. Bad intermittent connections can really foil ones trouble shooting steps. If your gauge problems are not just some sorta fuel reserve, then be careful not to disturb things too much when trouble shooting the circuit. Basically use your test light as a jumper wire. When used on the neg side of the fuel gauge circuit, you'll always get a dim light when you complete a broken circuit. And use new star type lock washers on all your bolted conections to secure good connections.

BTW: Nice Boat.

 

[tobnpr]

If you need to replaced your senders- and don't want to do it again, consider solid-state ones; I installed Centroid senders a couple of years ago and they're dead-on accurate. I can tell within 10 gals how much is in each 150 gal tank. Custom order based on your tank depth, and calibrated at the factory.

http://centroidproducts.com/

 

[Steve Hiser]

Very unlikely, I agree with Frank. Follow his instructions, Most likely 1 sender failed, po used boat with one sending unit reading until the second one failed. I had the same issue when purchasing my 89 340. I would be surprised if your problem is not the sending units. Sending units are cheap and easy install.
Good Luck
Kevin

They may be easy to install if I could just find them. Do you know where they are on your 89 340sd?