Leaking speed or depth transducer

[CABixler]

I have a Beneteau 331 with the common Raymarine ST-60 series gauges. Had some zebra mussel issues which as it was getting way too cold in Lake Michigan to clear from the water I pulled it out and slipped the dummy plug in.

They are the Airmar black plastic style. I was surprised on how little water gushed in. I later found they cleverly have a flapper valve that slows down the flow. During this spring I tried to match the o-rings as some were cracked. Surprising not as easy as it sounds as they are unusual dimensions.

Anyway I am in the water for the year and getting some very small leaking. Maybe a 1/2 cup a day? I love the molded in frame Beneteau has around the transducers.

I did not tighten too tight by hand. Just a gentle snug. I also was going to remove again in the water and try smearing a bunch if silicon grease on and re-seat.

Any feedback would be appreciated.

Thanks!!
Craig

 

[arf145]

While I don't have a leak, I have a related issue regarding those tricky O-rings. I put two new O rings in the bottom grooves of the replacement plug, thinking they were lost by previous owner and now cannot pull the plug out more than an inch to get the speed wheel back in. I'm wondering if the plug didn't need any O-rings down low. Did your plug have any O-rings in the bottom grooves?

 

[CABixler]

While I don't have a leak, I have a related issue regarding those tricky O-rings. I put two new O rings in the bottom grooves of the replacement plug, thinking they were lost by previous owner and now cannot pull the plug out more than an inch to get the speed wheel back in. I'm wondering if the plug didn't need any O-rings down low. Did your plug have any O-rings in the bottom grooves?

Wow what a tough problem. I'm sorry I don't know or remember but I measured the dummy plugs today for a reference and I have o-rings on the bottom two grooves but may have put them on during the winter.

I would guess the flapper valve may have snagged?? They are keyed when fully seated but you can twist when pulling out. I wonder if you re seated and tried again with gentle twisting it would help?

I just can't believe they would but grooves there if there wasn't a need for o-rings.

But good luck...
Craig

 

[Ron20324]

I put a dab of K-Y on those rings when I put in either the dummy or the wheel. Have not had a problem in 8 years. BE cautious, though, when you pull the depth unit. There is no flapper in there, and it is a bit bigger. and it floods more!

 

[BarryBershad]

I have been told to use silicone grease on those o-rings. I have the same style boat so lplease post the correct sized o-rings if you find them.

 

[DougM]

I have not looked recently, but Airmar has a website, and you can find schematics for the transducer bodies on the site. They are dimensioned which could provide information or at least clues as to the O ring sizes. I cannot imagine that they would be anything other than a common size.
One thing to look for is that one of those tiny baby zebra mussels could be caught in the sealing surface, and that could cut the O ring surface or prevent a complete seal. Those things are nasty. the shell edges can be like razor blades.

 

[CABixler]

I have been told to use silicone grease on those o-rings. I have the same style boat so lplease post the correct sized o-rings if you find them.

I did order a tube of silicon grease and will try maybe this weekend if It is still dripping.

My best estimation of the sizes of the O-rings that seem right are:
1 3/8" ID
1 1/4" ID
7/8" ID
ALL are 1/8" thick SIZE.

I bought 3-4 of each.

THESE SIZES APPLY TO BOTH THE SPEED AND DEPTH.

Best Regards,
Craig

 

[CABixler]

I have not looked recently, but Airmar has a website, and you can find schematics for the transducer bodies on the site. They are dimensioned which could provide information or at least clues as to the O ring sizes. I cannot imagine that they would be anything other than a common size.
One thing to look for is that one of those tiny baby zebra mussels could be caught in the sealing surface, and that could cut the O ring surface or prevent a complete seal. Those things are nasty. the shell edges can be like razor blades.

Good feedback by all. I appreciate it. I did try to clean the best I could when I was on my cradle. I did go to the web site and Jamestown Distributors carry the PDF's of sensors.

Here is what I found:
[*]Use silicon grease or Vaseline
[*]They always show the two lower O-Rings
[*]They mention it can snag if there is a break in the O-Ring on the flapper valve

 

[Gunni]

Like many things marine, they are not Beneteau, they are Airmar, distributed by Gemco. Gemco sells the replacement parts, including o-rings. There are 3 for speed, 2 for depth. There is a kit that provides paddlewheel, axle, and o-rings available from Gemco. I'm guessing you have the Airmar ST800.

 

[CABixler]

Like many things marine, they are not Beneteau, they are Airmar, distributed by Gemco. Gemco sells the replacement parts, including o-rings. There are 3 for speed, 2 for depth. There is a kit that provides paddlewheel, axle, and o-rings available from Gemco. I'm guessing you have the Airmar ST800.

Thanks Gunni,
I should be set now. I did start out calling Gemco and they needed the p/n which they said is on the instrument side at the wheel. I did not check but think I have a good match. Mine is the older one.

Craig