yamaha 3.0 l4 blew head gasket help!

[Flashcardsgo]

Looking back at the pics, it appears silicone was slathered upon a gasket and installed. I guess that's better than nothing, but there are better sealants to use for this - but not with one that ever had silicone on it before. I'd make a gasket and put some Permatex #2 or #3 on that thing. Silicone has a tendency to lubricate gaskets, making them slip and "squirt" out between surfaces. Silicone is a great sealant to use on it's own for when there is a gap between parts, but there are superior things to use when there isn't and there is potential for a gasket to move.

If I have to take it back apart I will make another gasket out of the material I bought . I’m getting really frustrated after all my work I’ve done and not being able to find gaskets and parts it’s just real frustrating! I tried to start it today with muffs on. It was real hard to start and motor was shaking trying to start. It did start after a dozen tries but it was really loud and I didn’t let it run long. It sounded like a car with the muffler off. . I’m about ready to let it burn or a tree fall on it lol. Just kidding but I’m really having a time

 

[Flashcardsgo]

You can make that one too. One can find some gasket making sheets at most auto parts stores. I have made riser gaskets out of the thicker gray colored gasket material. Slather that thing with some Permatex #2 and it won't leak.

Hey brother. I appreciate you expertise on my body motor. It’s been a job for sure so hard to get to anything and I’ve had some bad breaks besides impossible to get parts. I thought I was over the hump after fixing the broken bolt in the manifold and reattaching the riser ( I used red permetex because it said for high heat ( exhaust ) purposes. Anyway I got it running today it was very hard to start and when it did run it was extremely loud like a car with a bad muffler. Nothings leaking at the manifold or riser or the boots . My biggest nightmare is it’s the metal piece under the boots that bolts to something under the motor. It’s totally non accessible and I have no idea how to remove it or see it or anything. If it’s broken or cracked and it can be removed I can get one from the guy I got the head , manifold etc from . It seems the only way to get to that would be pull the motor which I definitely don’t want to go down that road. Any advice , suggestions etc. thanks. Tom .

 

[kd4pbs]

Well, it will sound like a car without a muffler on the outside of the boat because literally there is no muffler. You should not hear any exhaust sound on the inside and should not see any water leaking into the bilge while running the engine on the muffs. In order to replace the gasket at the bottom of the transom assembly where the exhaust goes outside of the boat, you would indeed have to remove the engine. The exhaust on your boat should never get anywhere close to the kind of temperatures that one would see in an automobile due to the fact the exhaust system is surrounded by water jacket. The problem with using questionable sealing techniques on the riser gasket is that water might be leaking into your exhaust ports without you even knowing. Hang in there, you’ll get there eventually.