Acid Flush - thought you all should know

[Jesse Delanoy]

I performed a muriatic acid flush this weekend, in preparation for winterizing my engine. I have a plastic Vetus waterlift muffler, installed about four years ago when I repowered with a Moyer-rebuilt engine.

After letting the acid/water solution sit for fifteen minutes, I cranked up the engine to flush out the acid. My water lift muffler blew at that point, splitting along the top seam. I was able to run a couple of 5 gallon buckets of fresh water through the engine after that point, by physically holding the Vetus together by hand, on top of a rag. I hope I got the acid out so that no further damage is done inside my engine or exhaust line.

Now I have to have the waterlift replaced, so I can run the engine to make sure I don't have any leaks, or water getting into the oil, etc. I think I did an acid flush a couple of years ago, with the same equipment on board, with no obvious ill effects.

Don's instructions say to use 1/3 gallon of 50% acid solution in a 5 gallon bucket of water. The acid I was able to buy indicated it was a 20% solution, so I upped the amount from 1/3 gallon to about 1/2 gallon. Even using a 50% solution, I wouldn't have thought this slightly greater concentration would be enough to cause damage.

Assuming no severe damage done, I guess from now on, I'll be doing vinegar flushes and pressure flushes.

Jesse Delanoy
1977 Catalina 30 "Off The Grid"
Baltimore/Pasadena, MD

[ndutton]

Your experience solved another completely unrelated dilemma for me (see Concept Opinions thread) but I'm struggling with the thought that the acid solution itself damaged the plastic waterlift muffler. The muffler should have been impervious to the solution.

Any chance there was an exhaust blockage within the muffler as a result of the acid flush? The last time I flushed mine I was surprised how much solid material was expelled. This really sounds like an overpressure condition to me.

[lat 64]

I'm with Neil, something got plugged up. If the acid did ruin the
Vetus, then the plastic muffler doesn't sound like it's any better than the jug the acid came in. I'm sure that's not the case.
I don't even think the engine could blow the seam. Wouldn't it die from back pressure first?
I wonder if (not a qualified opinion) that the seam in the muffler was already: defective, compromised, or cracked, and you found it at a good time when you weren't out on the bay.

Russ

[Dave Neptune]

Wow!

I agree with Russ unless the glue in the seem was vulnerable to the acid which I seriously doubt. Could have been a bit more back treassure expelling the dislodged and not necessarily disolved KRAP.
I think the most likely senario was the muffler was about to fail anyway.
If you got some acid in the bilge it shouldn't attack anything unless it is metal. You could flush with some baking soda if your worried. It is pretty easy to clean up. Even a fresh water rince would dilute to the point that there would be no worries.

Dave Neptune

[Jesse Delanoy]

Thanks for everyone's input. I agree that the acid should not have attacked the waterlift muffler, and perhaps it was ready to go anyway, but it's only four years old. Seems very odd. On the other hand, I'm very glad that it went in the slip, and not out in the middle of the bay - It'd be a tough motor back to the marina, on my knees in the cabin, gripping the waterlift tightly with one hand for a couple of hours.

I think I took care of any external acid spillage - mopped up the outside of the engine with baking soda solution, put some baking soda in the bilge, hosed it full of water and pumped it out a couple of times.

One of Don's posts indicates his thought that once the diluted acid solution reacts with the crud in the engine, it largely neutralizes itself anyway, so hopefully I haven't done any internal damage. I've already scheduled the muffler replacement, then I guess I'll start her up and examine closely to make sure nothing's leaking anywhere.

I'll check hoses and fittings for leaks, make sure I'm not getting water into the oil or the cylinders from the water jacket. I'll probably replace the impeller next spring anyway.

Any other thoughts? Thanks, guys.

Jesse Delanoy
1977 Catalina 30 "Off The Grid"
Baltimore/Pasadena, MD

[ArtJ]

Maybe you might consider a different brand of muffler, just in case?

[keelcooler]

This failure spot lights the weakness of the molded non reinforced plastic vetus type water lift mufflers coupled with a gas engine. They often fail the cheery bomb test and blow at the center line seam. Hard starting and/or flooding sometimes provides the right air/gas mix for a significant explosion within the muffler itself in the event of a back fire or similar spark introduction. The SS and fiberglass units are far superior in this regard.

The vetus units are often selected based on price, ease of pipe routing installation and it’s the only one that will fit in the bilge space. They also melt/degrade rapidly in the event of a overheat/water blockage.

[hanleyclifford]

For which reasons a spare should always be on board.

[ndutton]

FYI, I've had three different types on two different boats:

My Westsail with the Perkins diesel had the Vetus.
Kalina originally had a stainless waterlift, had pinhole leaks at the base welds.
Kalina now has a Centek fiberglass, love it.

In agreement with Keelcooler, I felt the Vetus was lightweight and flimsy. I had no problem with it, just my opinion. When it became obvious Kalina needed a replacement, the Vetus was never considered.

[sastanley]

Neil, I think the stainless was the OEM product on Catalina's. I seem to recall that the Vetus had been in place on my hull #511 for many years (20+) - When I acquired my boat from the P.O., I found the OEM stainless muffler in the bottom of the sail locker. It too had pin hole leaks in the bottom seam. I stored it at home and thought many times about possibly repairing it, but couldn't find any 'buddies' with stainless welding supplies and figured if the Vetus ever fails, I'd either go to a new stainless or maybe the Centek..I am happy with my other Centek product, a 45 degree elbow I bought which replaced the funky bronze 'flapper valve' in the high point under the port winch.

Incidentally, I recently found those one way bronze flapper valves at Lowe's for a significant savings over the West Marine equivalent..probably both are still plagued with the mild steel rod holding the flapper in place.

[ndutton]

Incidentally, I recently found those one way bronze flapper valves at Lowe's for a significant savings over the West Marine equivalent..probably both are still plagued with the mild steel rod holding the flapper in place.

Why couldn't that mild steel pin be replaced with stainless? Could be a good little project, like I needed another one!

[sastanley]

Neil, I actually did that, but when I discovered the flapper valve was built for 1 1/4" hose and most of us have 1 5/8", I got the Centek elbow instead. I still have the flapper valve in my box-o-boat-bits in the attic, just waiting for me to have 1.25" hose somewhere that needs a one-way valve

I think I found 1 1/2" at Lowe's and maybe as big as 2"...