outboar exhaust mod

[stclairriverblaster]

i wanna make this thing louder but ive heard that drilling holes can cause problems.. what can i do ??

also i read about having to remove the can in the midsection.. i dont see a can but i see this.. what does this mean or do ?

http://i196.photobucket.com/albums/aa295/stclairriverblaster/checkmate/dawnshouse047.jpg

[jallen355]

I get alot of comments on the way my motor sounds. It's a bit loud and has a good rumble to it, but it's not excessively loud. Comparitivly speaking, I can't say it sounds better or worse than anything else as I do not have alot of outboard experience. The majority of the boats I've owned have been "car motor" boats.... :) But I do like the way my "egg-beater" sounds. Seems I always get asked "what motor is that" when I crank it up at the launch. I usually get embarressed to admit that it is a stock 150 hp "fishin' mota". :sssh:

I have no "can" in my mid. Looks like you don't either.

I get exhaust coming out of the two rectangular holes on the backside of my mid just under the cowl skirting which is above the waterline. According to those in the know that I have spoke to, these holes are "usually" not open from the factory but alot of folks do drill holes inside of the rectangular "bosses". Me and my buddy had our boats out on a sandbar this past weekend and were comparing these holes on our mids. Both motors are just plain old "fishin'" mota's. His is a '91 2.5L/175hp and mine is a '89 2.0 150hp. If you look at the rectangular holes in both mids, they are both blocked...at first glance. Mine, however, are opened up in the top of the holes. You have to look into and up inside the rectangular holes to see where the exhaust is coming from. I know nobody did this as it would be pretty tough to drill holes in the roof of the rectangular ports. Either way, you could drill holes in your mid inside these rectangular ports IF they are not already there. You WILL get exhaust flowing through them w/o a can in place. So if you have never had a can installed and do not have exhaust coming out of the ports now then you would have to drill them.

Another method is to drill "termite" holes in the backside of the mid section on either side of center. Usually these are 1/2" holes, but I have seen them bigger than that. Again, you have to have to can removed to get the effect of louder exhaust. I have heard that this method can produce cracks emitting from the holes over time, however.

Yet another method calls for drilling holes or cutting a rectangular hole on either side of the mid in the underside of the cavitation plate. These can even have plates fabricated to block them of when needed. There's several articles on this mod over on S&F.

[stclairriverblaster]

Yet another method calls for drilling holes or cutting a rectangular hole on either side of the mid in the underside of the cavitation plate. These can even have plates fabricated to block them of when needed. There's several articles on this mod over on S&F.


thats exactly the mod im talking about. but i heard that drilling holes causees it to crack
is this the same with makinga hole ? i love the sound of my outboard out of the water with the ears on.. :lol:

[jallen355]

I have not heard of any probems with cracking on the first (like mine) of the last method I mentioned above.

Here's a link to the last mod I mentioned above. It seems to be the most involved...

http://forums.screamandfly.com/forums/showthread.php?t=21458&highlight=exhaust+mod

[stclairriverblaster]

ok well comparing pictures. i still have the can in place..
if i remove the can will i need different "tuners" or will the ones pictured stay in place ??

anyone got a crash course on removing a powerhead ? ?

id like to upgrade to solid mounts while im at it

[illMATTic]

i should have drilled mine when i had it apart. now im all back together and am sorry i didnt drill it out.

if you pull the can out you will cook the paint on your mid. you can take it out and cut the bottom sides out if it and re install it. the holes in the can will be right above the holes you drilled in the mid.

[powerstroker]

anyone have a picture of the can you have to remove? and what tuners do you need i have been trying to figure out how to get my yammie louder for a while now and i dont mind drilling whole because i am a welder and i do that crap for a living but is the easiest thing to relieve some exhaust so its louder? is the can the best and easiest? if you need pics of what i have on it now i can upload some just tell me what you need a picture of! thanks:eyecrazy:

[illMATTic]

all this talk here applies to mercs. i am sure a yammy is similar but you would want to investigate further.

[Reed]

I have what is called a " exaust manifold that is a rectangle with 2 holes pointing down towards the water and it is welded to the mid-section and hides the 2 , 1/2 in holes that were drilled in my mid section. I love the sound when I get out of the water and plain off... ( It sounds like a Indy car )

[wizard8575]

this is always an option...:surf:
http://i137.photobucket.com/albums/q233/wizard8575/offshorexhaust.jpg

[stclairriverblaster]

id be down for something like that LOL

im thinking of doing a offshore dump instead.

[wizard8575]

http://www.youtube.com/watch?v=1DhH3feoLXo

[HobieHernandez]

I was told by a johnson dealer not to mess with mine,The Gt200 has a tuned exhaust and I can wind up loosing power..I was looking for the big sound too..

[175checkmate]

I performed the exhaust mod using the step by step instructions in the link. Worked very well. My can was removed during the rebuild so I did not have to mess with that. The parts that where cut off to allow access are drilled and taped to be used as covers if I ever have to be quite. The mod works and sounds great. Not to loud at an idle because the cut outs are under water. Get on plane and it sounds great.

[Reed]

this is always an option...:surf:
http://i137.photobucket.com/albums/q233/wizard8575/offshorexhaust.jpg

WOW I bet this is a loud one lol