Silicone coming off intake path again...

[tdonoughue]

So, it has not been that long since I pulled the pumps and, while they were out, recaulked everything with some nice silicone caulk. All the gaps, the hex bolts on the grate, etc. Maybe 3 years ago?

At any rate, took friends out yesterday, but we got there early as it seemed when we brought it in last that there was something stuck in one of the pumps when we came in. Got there early to check it out before everyone showed up. Turns out just found some dried foliage hanging from the grates (and no issue once we hit the water), but while digging around there to make sure everything was fine, I noticed that much of the silicone I had put on there is gone. Most of the gaps are all back. I think all but one or 1.5 of the hex bolts are uncovered again.

Not as effective/long-lasting as I had hoped.

So, then, to my materials-based question, please: What, exactly, are you using for resealing these gaps? Apparently my GE silicone caulk isn't the thing to use. Are people using 4200? Seemed a bit much to me originally, but given these results... Certainly don't want to do 5200 (what if I need to replace a grate or something?). Or something else? Thanks.

 

[feziwig]

I’d use something marine specific. I used 4200 on mine. It’s holding up well so far, but I just resealed everything this year.

 

[drewkaree]

I don't recall all that you did, but I wonder if it's being slowly eroded when at speed, or the adhesion wasn't that great to begin with? Silicone won't stick to silicone, so any remnants or film left over would eventually fail. 4200 might be the solution, but adhesion is still going to be a concern. Maybe a test spot with some 4200? I know a few years is a bit long to wait, but do a few areas with 4200 and a few with caulk, or else just go whole hog with the 4200 since you're doing it? Worst case scenario, the 4200 gets washed out as well, but you get a first-hand experience with the longevity comparison.

 

[zipper]

Look up Lifecalk or Lifeseal. Na, nevermind, here is a link. Boat Caulk & Sealant - USA Made Shop Now | BoatLIFE

Lifecalk is a polysulfide based sealant. It is paintable, sandable and flexible. It will react with some plastics, but not gelcoat.

Lifeseal is a mix of silicone and polyurethane it is not paintable and will not react with lexan or plexiglass. I used this to rebed my portlights and other uses on the boat.

 

[mrcleanr6]

3 years is quite a long time. That jet pump is an area that takes alot of abuse. I would not expect silicone to last in there that long. Imo your pump should come apart for inspection before each season anyway especially if you boat in salt.

 

[zipper]

Marine silicone is what Yamaha uses and calls for in the service manual. GE silicone is not that.

 

[2kwik4u]

Or something else? Thanks.

I used "something else". Loctite ProLine Fast Cure Marine Sealant.

My Intake Tunnel Reseal Thread

Was under the boat a few weeks ago and it looks like most of it is still there. I first applied it in May of 2018, and it's still in decent shape. Best I can remember (I don't log hours as diligently as I should) I had maybe 50hrs on the boat at that point. I have just a shade over 175hrs now.

 

[zipper]

I stand corrected...I just looked in my 07 service manual and all they use is "silicone", nothing mentioned about marine grade. I would try something for the marine environment.

 

[David Martin]

GE typical hardware caulk is not going to be tough enough for the intake tunnel. Yamaha/or 4200 would be a good choice.....the only caulk a hardware store will come close is a gutter calk that is a non water-soluble caulk gutter caulk is alcohol/acetone cleanup.....this type has a higher adhesion factor like the 3m 4200.

With that said 3m 4200 or the gutter type caulk do require a vary clean surface to adhere to so clean up with acetone in affected area will be vary important.

 

[1WetBoat]

In the waverunner world we use Right Stuff black gasket sealant around bolts holes etc. to seal it up. For the intake grates where it touches the transom/tunnel they use 3m Fast Cure 4200 and it tends to hold up real well.

 

[tdonoughue]

Thanks, folks. All very helpful. Additional data points/responses:
- Usage has not been heavy over the last 3 years, so that is why I was a bit surprised to find so much gone. The stock stuff lasted 6 years of heavier use...
- I don't think I put silicone on silicone much (maybe at the edges?). The original stuff was pretty much gone when I redid it...
- I boat in fresh, but still the point about the jet path taking quite a bit of abuse is quite correct.
- I did not clean up with acetone--that is an excellent idea.
- Lots of good product ideas here. Appreciate those! Will probably do 4200, then, as I think I may have some of that handy. Otherwise that Life stuff looks pretty snazzy....
- Came across this caulking tip from home improvement circles: wear latex gloves when caulking. Not only is there nasty stuff in there, it makes cleanup much easier. Duh. Why didn't I think of that years ago?

 

[tdonoughue]

Had to pull one of the pumps to rid myself of some fishing line, so decided that it was time to fix this issue. Photos attached. Caulk was a little better than it felt from up top. But still some significant gaps. My 4200 was a little old and drying out already, so it was very tough coming out of the tube. Gave my hand a workout. But cleaned the area with acetone and got all the gaps filled (not quite as smoothly as I might like, but far better than it was.



On the upside, the impellers looked very good. Last time I pulled the pumps I had a number of dings to fix in those. But they actually looked ok.



We will see how this one goes.