Off the top of my head I cant recall what exactly needs to be done but zincs need to be changed from fresh water to salt water. I think Jeff may know exactly what types are best suited.

Be sure neighbor boats are not contributing such as faulty shore cords.

Check the analog meter with a digital meter and calibrate as needed.

Short the shaft(s) to the engine and see if the meter needle deflects. If the needle deflects while shorting your shaft(s) are isolated. Use 2 people for this test.

I have found colder water give better readings, at least in fresh water.

-Karl

Jeff,
I don't think you wrote what you intended, Your last statment is correct, 0.9 -1.2.

Roger

Let me be clear on this. Do you really mean .1 (barely reading) at the very very low end of the scale...or 1. which would be in the upper range of the scale? If the former, you have a problem. If the latter, you are right in the groove, no problem. That decimal point placement is key.

As already noted, different type zincs required in fresh vs salt water. But here is where my brain shorts...I am not sure but I think the aluminum/zinc bar is for salt water and the other kind (magnesium?) for fresh. I will gladly edit this post if someone straightens me out. If we could go back more than 6 months in searching the site, we'd have the answer for it has previously been posted.

If you have point-one reading (low end of scale), you have to start work. If you were getting ok readings at your previous location, and haven't changed anything on your boat then I'd look for external factors (like the zincs) and the other boats' hookups and the power feed to your boat. Usually, AC current is not your big enemy, DC is.

(BY THE WAY: While this is a good post it does not belong in the "Althouse" category. It should have been posted in REPAIRS/electrical&corrosion)

The Capac meter that came with the boats had a 1 to (something) scale that really meant 0.1 to (something) volts.

Jeff

Trouble! Could be a bad probe. Are you using the original Capac meter head?

Jeff

Depending on the age of the unit there is a little water resistant cylinder in the bilge which houses the butt connector from the sending unit to the meter. I found mine to be a little green/corroded. You can unscrew the cylinder ends and inspect the connection. Perhaps water got into the cylinder if you have one and the connection is deteriorating.

Another thing to check is make sure the yard or whoever does the bottom paint did NOT paint over the sending unit.

If you use a digital meter you will be able to tell immediately if the analog meter is shot.

If I'm reading the numbers correctly I think its 0.3 >> 0.6 >> 0.9 >> 1.2 >> 1.5

-Karl

Anthony,

I’m not sure on a 72 sedan but on my 89 F/B sedan it’s under the galley table decking on the port side a bit of a job to get to. Plus a pic # 678 of the sensor. If your vessels outta the water look along the bottom than U'll know exactly where to start looking on the inside of the boat the connection that Karl mentioned is just above the sensor. Here’s a better view of the capac meter hope this helped

Norm,
Bigs Live On

if anyone needs a connector like that it's the same as is used in connecting a deep submersible well pump.even though most people just use black tape. thats what your suppose to use.should be avalible at lowes.


tim

I was thinking , since I have an account with a marine supply company I would just order an entire set of zincs for my boat so when I pull her this summer (next named storm) I will have an entire set I can replace as needed and maybe strut and shaft bushings while I am at it.
Question is how many and what types, sizes, shapes of each will my 72' 32 sedan bridge require?
Anthony