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As many of you know, I ordered an HT-40 manifold set from my local Marine Torq dealer in order to prove out the process for the Group Buy going on now. This thread documents my progress at replacing my iron manifolds with the stainless steel set. First, a bit of background. I use my boat nearly exclusively in salt/brackish water, so my manifolds were on a time delay fuse to rot out from the insides. I bought the gently-used boat (a 1999 Sunsetter LX with Monsoon II engine) in the fall of 2013, and by spring had converted the engine to half-closed cooling. This protected the block, but left the manifolds cooled with salt water. I changed the riser gaskets and the exhaust (and fuel) hoses also. I mainly changed the riser gaskets so I could assess the manifolds and risers and estimate about how many years I might be able to put on them. The last thing I wanted to happen is have a leaky riser that dumped water into a cylinder, which would surely lead to a catastrophic engine failure. I looked around from time to time, but didn't find anything available in all stainless for a reasonable price (before you tell me about them, "Stainless Marine" is aluminum with stainless risers). I was looking and asking around this summer when I discovered the possibility of getting a group buy to help reduce my cost. You can read more details about acquiring and inspecting the manifolds in the Group Buy, but I finally have them in hand and ready to install. Here we go! The HT-40 manifold set as delivered:

Hello New to the forum and in desperate need of help. Last year about this time I purchased a 2009 Malibu Wakesetter 247LSV. Instantly the family and I fell in love with it due to its size and features. I took the boat in to get serviced and found out the port side exhaust manifold had a crack in it. The service shop did a pressure test and it was dumping water. I searched everywhere and could not find another manifold here in states. I branched out and contacted Indmar Marine in Australia and found they had several in stock. I quickly purchased 1 and waited over 8 weeks for DHL to get it through customs and delivered to my door step. The new manifold was installed and we were able to take the boat out again 4 more times before we got struck with a catastrophic failure. The motor let go, apparently spinning bearings and even developing a crack in the block. I paid for Jaspers Motors to build me a brand new motor and had it installed. After the service shop took the boat out to do water testes, they discovered that there is water on the O2 sensor on the port side. The new exhaust manifold again with 4 runs on it supposedly developed a crack as well. The exhaust manifold was removed and pressure tested as well. This time it held air pressure at 15psi and water pressure at 40psi or what ever the pressure is that comes from your garden hose. There wasn't a leak. After installing it again and starting the motor, after it would heat up, water would start to come from the O2 port again on the Port side manifold. So my mechanic is assuming that when the manifold heats up, the cast aluminum expands and allows water through. Unfortunately there is no way to test it off the boat at operating temperature. Due to a Nationwide shortage, we are having zero luck locating another manifold and facing a year of no boating. I was told that they use the same manifold on different boats but unfortunately Indmar does not have a cross reference for what other boat manufactures those are. We are desperately searching everywhere for a new or even used one that might be sitting on a motor at a salvage yard. Has anyone heard what other boats these may come on? Do they make aftermarket or performance headers that I can replace the stock ones with? The Indmar part# is 531401HL. Any help would be greatly appreciated!

someone stepped on the tray over my engine and broke the freshwater fitting off on my manifold. is there a way to get the broken fitting out of the manifold?

I have a 2007 malibu 247 RX. One of the zinc plugs in the aluminum exhaust manifold blew out. How do I fix this? Also why do they have the plugs? Is it like a freeze plug. If so what should I be looking for that caused the plug to blow out? My exhaust manifold is polished aluminum. The ones I see online are black. Any difference in the two other than color?