Floscan 236C senders, can they be opened and repaired?

[zigzag930]

Has anyone successfully dis-assembled their Floscan senders to diagnose and/or repair them? Are they gear drive or optical?

My starboard engine is reading only 2.4v on both fwd and return senders and I think the mechanism inside may be "gummed up" or sticking. Other engine, the senders show 5.8v which is in line with what the troubleshooting guide specifies.

[Captain Ralph]

There is a diagnostic mode you can enter on the diesel displays. It will show the tics per each sender. Usually the 236C is a return sender.

Because of the way my senders were installed, removing it was to be a chore.
I was getting no signal and my engine was showing making fuel. Ha!

I found a lone sender for sale on e-bay and went for it.

Torx security screws were used during assembly and I just replaced the brass head. Still a pain.
Getting the tic signals I thought it was fixed until I started operating the boat. Calibration way off.

From the factory, senders and displays are matched and thermally calibrated together. I messed that up. One day, when a lot of down time is expected I'll rip everything out and send them in for re-calibration.

Later on some other boats, there were tic signals but slow. a big dose of Diesel Klean into the Racors, ran engines for a few seconds and turn off. 15 minutes later run the engines a few seconds and turned off. We had no idea how fast the Diesel Klean would reach the senders. We filled the Racors up a few times and keep running the engine a few seconds at a time.
We washed the boat, cleaned the bilges to kill a few hours and then ran out of beer.
Buttoned up and ran the engines at idle and all worked fine.

If your getting the tic signal, you may just have some goo on an optical paddle wheel. Try to get a good dose of fuel cleaner in there and let soak a while.

I don't recommend opening yours up, but it is a guys nature to explore. Watch out for the lil O rings.

The better fix is, take the senders and display, send them to Flow Scan for repair and re-calibration.

[zigzag930]

I have the in diagnostic mode and port engine shows 29-30 GPH supply and about the same on the return side at idle. At 1000RPM I see 45GPH supply and a bit less on the return, so it looks like that side is working ok. However the display shows 0 GPH when I return to normal (non-diagnostic) mode.

On the starboard side I show almost no flow or return GPH. This is the side where the voltages are lower (2.4vdc) as contrasted to the seeming working side which registers 5.8vdc

I do have 13.8vdc at all senders. They are all 236C type (for DD471)

Guess I better not open them up. They are in a difficult place to reach, but maybe I can pull the one side (starboard) off and try to blow some compressed air thru them?

[Captain Ralph]

I have the in diagnostic mode and port engine shows 29-30 GPH supply and about the same on the return side at idle. At 1000RPM I see 45GPH supply and a bit less on the return, so it looks like that side is working ok. However the display shows 0 GPH when I return to normal (non-diagnostic) mode.

On the starboard side I show almost no flow or return GPH. This is the side where the voltages are lower (2.4vdc) as contrasted to the seeming working side which registers 5.8vdc

I do have 13.8vdc at all senders. They are all 236C type (for DD471)

Guess I better not open them up. They are in a difficult place to reach, but maybe I can pull the one side (starboard) off and try to blow some compressed air thru them?

Hello
I'm sure you fixed the low DCv to the sender but I have to ask;
Was there a final solution?
Thx
rc

[zigzag930]

Well, not exactly a great answer - but here's what happened:

I pulled both gauges and sent them out to Joe D to have his guys test them. He said they looked ok, but they really couldn't do anything with them anyway.

I put them back into the dash and now one is working pretty much as it should. The other gets intermittent flow rates.

For now, I have decided not to chase it any further. I'll just double the total gallons on the working one and call it a day.

[Captain Ralph]

I have been searching old FloScan threads to compare my findings last week with others and this thread popped up.
I was working on later 231 diesel senders, one developed a low resistance (near short) on the 12Vdc supply and kept both senders down. When I started messing with them, their 1/2 A fuse finally blue.
I just happened to have a 231 sender from my ole shop. Splashed that bug.

It read like you had the same problem.

Per Joe last week, They don't work on the old stuff anymore. Their new products only.

Let me know if/when you start chasing down your bug again, I may be of help.
I think also, a couple of 236Comp senders still in the shop.
Thru the years, seems I have collected a bunch of this ole stuff albeit mostly gas applications.