Old exhaust system

[Kruggy88]

I originally posted this in the general maintenance but realized it would be better here.

I just pulled the port Crusader 454 out of my 1993 carver 638 santego. My engine got hydrolocked and it appears I did some bottom end damage. Hoping to confirm it next week.

I am fairly confident the water ingress was from the intake manifold. I have always had water drain from tithe cockpit floor onto the cover of the carb but we had some major rain storm and it must have leaked enough water to fill a cylinder.

I am preparing for the rebuild and starting to think about replacing exhaust system or keeping the old ones. The exhaust ports on manifold, riser, and elbow are completely dry but I have every reason to believe they are original. I have a raw water cooled boat that has spent its entire life in Wisconsin boating on fresh water.

My mechanic said if they look good than it’s not worth the $2000 to replace. From everything I hear on the internet, it sounds like it is completely nuts to put 33 year old manifolds, risers and elbows on a freshly rebuilt engine. I don’t know how much I will be into the rebuild but I am assuming at least $5000, so I would love to save money where I can but the last thing I want to do is blow up the motor again.

I was hoping to get some opinions from seasonal fresh water boaters that have or haven’t replaced their exhaust system.

[waybomb]

I have an 87 Mariner, Crusaders, original exhaust. Been in lake Michigan the whole time.
No issues

[Kruggy88]

Yes, I wonder if most of the super precautionary people are salt water boaters. They still look great, there is some rusting on the bottom of the exhaust manifold, not sure if that was from the heat of the exhaust or a gasket leak.

[bud37]

Welcome to the forum.

So my opinion here....it is one thing to be thrifty but in this case the least you could do would be to have them pressure tested and gasket surfaces cleaned and levelled , even at that you can't see the inside passages which can be where the pinholes and water comes from many times, plus at this point you really don't know how the water got in there....may have been reversion or ?? just sayin.

Brand new engine deserves new stuff, too expensive to cheap out and put ancient parts back on, not just precautionary but wise.....good luck with your refit.

[Carverlvr2]

If the manifolds and risers are still in that good of condition, sell them to recoup some of your cost for the new stuff.

[Kruggy88]

To those saying to put new ones in, what do you recommend? Oem is no longer available and from what I have heard aftermarket is hit and miss.

Water coming in thru the carb to flood the intake manifold is the only things that makes sense. The engine did not over heat, I didn’t make an abrupt stop nor take a big wave to the transom.

[waybomb]

How did water get into the carb, no flame arrestor installed?

[Kruggy88]

There is a crack around the nut of the plastic cover. Exhaust channels on the exhaust manifolds are bone dry. No sign of water ever being in there, only dry carbon deposits.

Engine has ran great all season, no sputtering, no hard starts.

[Kruggy88]

We had almost 11” of rain from the time I shut down the engine to trying to start it again. I have simulated rain now with a hose and it is a steady stream of water the lands directly onto the carb.

[Viper]

I always say that one's wallet usually dictates how someone will proceed even when it's against better judgement and professional recommendation, and for SOME things that's okay. Well, for what it's worth, in this case, here's my professional recommendation; replace the exhaust. Might your current ones be okay? ya but nobody will give you that 100% guaranty, and if they do, get it in writing, I doubt though that you'll find someone willing to do that.

I've found over the years that with SOME things, one's thinking has often been backwards, it's not that you're saving $2,000 by using your old exhaust, it's that you're spending $2,000 to avoid another $5,000 bill for another engine should the old exhaust fail, not to mention another blown summer. Oh, the other thing I always say is "pay me now or pay me MORE later." That consequence of taking shortcuts never fails!

Having said all that, you need to do something to prevent water from getting into your engine.