Lower unit caulk?

[Gabby]

All right you smart MerCruiser mechanics. Need an answer.

I have been applying Peel Away to my hull to get AF paint off the boat. Then I scrape with a wooden putty knife, then scrub then clean, etc. Around the lower unit where it meets the hull, there is a bead of white rubberized looking caulk. It looks too sturdy to be standard silicone caulk, and it is kind of rounded on top, not like a bead of caulk.

Is this a special type of material applied when the lower unit is placed on the transom that seeped out when the unit was tightened or is it a type of gasket? The peel away is breaking that rubber down and I can always caulk, but I want to make sure caulk is OK and it isn't something different that I need to have professionaly done.

Thanks.

 

[Haut Medoc]

Re: Lower unit caulk?

Not sure how old your rig is, but there is not normally anything like what you are speaking of from the factory mounting...
It sounds like something a previous owner did.....
Repair or just GP?.......​

 

[Scaaty]

Re: Lower unit caulk?

Beg to differ..my 77 Volvo has the same thing (original)..just ignore it and paint up to it...or peel it off and sink​

 

[Bondo]

Re: Lower unit caulk?

Beg to differ..my 77 Volvo has the same thing (original)..just ignore it and paint up to it...or peel it off and sink​

Ayuh,.......

And Your Volvo Isn't a Mercruiser Either........

Merc.s are mounted with a Big Black O-ring of sorts.......

Gabby,......
Whatever your looking at Isn't Factory,......
It's probably 5200 or Something that a P/O put on it in the past,.....
Which points to a Transom Rot Issue,.....
When the Transom Seal starts Leaking,...
It's Usually because the transom is Rotten,+ that causes slack in the mounting Bolts,......

This little Hint, Also says you should Pull the drive,+ Check the Alignment, as it's probably Off if the transom is rotting,+shifting.....

 

[Gabby]

Re: Lower unit caulk?

I had the drive off last year. Had to change the engine coupler and had them go ahead and change the impellar and grease the gimbal bearing all the bellows, etc. I figured as long as it was off they might as well go ahead and check it all. When the put her back together they said all was well I had no issues.

I am looking at the receipt and there is a charge for outdrive gaskets, which I ssumed was what I was noticing last night. So, I figure I have two options here Bond-O, correct me if I'm wrong.

1. Since they had it off and didn't mention transom rot, I can make the assumption it ISN'T rotten, and further assume that since the only part of this gasket affected was the small bit squeezed out when the lower unit was tightened, I could put some type of caulking material (5200?) around the area where the transom / LU meet and be ok.

2. I could assume nothing and take it back to a Merc dealer to make sure I am not going to sink as Scaaty suggests.

 

[Bondo]

Re: Lower unit caulk?

Removing the Drive,.... Doesn't disturb the Transom Assembley on the Transom.......
They Pulled the drive Off the Gimbel Housing,..... That's a couple of pieces Short of the Fiberglass Transom........
So,....... "They" would have No Way of Knowing the condition of the boat's Transom........ That's Not what you contracted "them" to Fix.....

Personally,......... I'd Assume Nothing........

Taking it to a Dealer is going to Co$t a $mall Fortune......
There are Plenty of threads, in the Restoration forum dealing with this Issue,......
Have a read,+ then Inspect it Yourself........