Mercury 1150 Exhaust Questions

[TNRoostertail]

Hey guys! I have been reading up on these old engines and it seems that unless you want to drop a large sum of cash there really isn't any power mods for the old tower of power. I have a 79 1150 and it runs great. I am however one of "those guys" who likes loud and fast lol. I would like to know if there is a way to make the engine louder without hurting performance? I have just had the xr and black max engines so I am used to how loud and wonderful they sound and would like to open this old rascal up a little more. Again I am aware there aren't any huge gains to be made I just want it louder is all. Thx

[rock]

T2 mid. Louder than you can imagine. Also consider a set of pipes. They are annoyingly loud. You can also make an opening in the lower where the exhaust passes thru and I imagine you could ventilate the mid in some sort of fashion. Even with any of that they do not sound anything like a v6.

www.youtube.com/watch?v=gOlhsvBp8Gs

Rock

[TNRoostertail]

Thanks rock, are there any write ups with pics on any of your mentioned procedures?

[TNRoostertail]

In the quest not to start a new post, how can I tell what year exactly TOP I have? I was told 78 but I would like to know for sure. Thx

[TNRoostertail]

This engine sounds beautiful https://www.youtube.com/watch?v=7AkXFuBvRX4

[Dave S]

Drop the lower unit..... Break the exhaust tube can with a chisel as far up as you can...... break the back of the housing that is simi round separating the exhaust from the back of the housing. don't do anything that is on the outside of the motor for looks.

[TNRoostertail]

Am I trying to remove it or just break it lose? Sorry I haven't down much past plugs and water pump and lower maintenance. Are there any pics or anything available for this?

[rock]

If you remove the lower unit you will see where the exhaust passes thru it. At that location you could drill a couple holes but keep in mind you are weakening the casting. On a v6 you can remove the exhaust liner and drill down thru the bottom of the can above the cavitation plate and that is the most common and does not show on the exterior but to some extent also weakens the casting. I do not have an inline apart right now to look but there may be some other more discreet ways.

Rock

[mrcrsr]

I've looked at mine (I'm going to run a factory 15" mid) only place I can see to relieve the exhaust is the gearcase itself, where the exhaust passage is up by where the mounting flange is. I've seen people cut a slot in either side. Can't drill down by the cavitation plate like a v6, it's not flat in that area.

[Dave S]

easy way.....just kick the **** out of the bottom of the tuna. the semi round is the thing that seps the exhaust from the back water...

[TNRoostertail]

Thanks rock, I will wait to hear back from you before I start. Also thx to mrcrsr and Dave, Dave are you secretly Arnold Schwarzenegger? That's what I pictured when you said tuna instead of tuner, no disrespect intended. I have the lower back off because I forgot to turn the gearshift back into neutral, I am looking at it and see the exhaust tuner and where it seats with the midsection. There was also a hard rubber gasket that helps them mate. I am still not understanding the "half round" part. Will this not just vent exhaust gases into the midsection with no where to escape? Sorry for all the questions I just don't want to screw anything up.

[TNRoostertail]

I am new to outboards so I want to clarify a few things with you guys first so I am sure to be on the same page. The top where the power head sits is the upper? The longer section where the driveshaft runs through is the mid? And the lower is the part you take off to do the water pump with the gearing and what not right? I see where what I call the mid and lower come together and how the exhaust tuna fits to the lower. From what I can understand you guys are saying to let the exhaust free vent into the mid? The gas will escape out of the 2 small exhaust ports towards the top of the mid? Now in doing this I will make props with the plugs useless right?

[rock]

Powerhead, mid section, and lower unit are the correct terminology. Not sure breaking exhaust tube, (tuner) will make a lot of difference but I may be wrong. Drilling a couple 1/2" holes in lower will probably make the biggest difference sound wise. Won't affect your prop unless you have removed plugs for hole shot. Holes in the lower will reduce exhaust thru the prop hub.

Rock

[TNRoostertail]

Well got everything back together after taking the lower end back off and marking where I could drill holes if I want. I haven't started it yet after the new water pump because I didn't set the gear selector right. This is the first fire after that. I have went through the engine and replaced all wires, plugs etc... Idk if I want to drill it out or not, it sounds pretty nasty the way it is. And I eventually want to trade this engine for a 200hp Black Max or other 200hp Merc so I do not want to do something that isn't reversible and knock myself out of a deal with someone who likes things stock. Here is a crappy vid shot with my phone. https://www.youtube.com/watch?v=jHcXX8ErFNM

[TNRoostertail]

Guys I have listened to a lot of other 1150 engines, about every one on you tube that is running on hose and they don't sound like mine. Could it be true that this engine did have work done to it in 1990? The guy told me it had a bunch of stuff done to it but that's about the same with every craigs list find lol. Idk may just be the way they are stock, you guys would know more than me as I have never had an inline TOP.