Mercury KE-7 tuned pipes

ryan 98

Petty Officer 3rd Class
Joined
Jun 23, 2013
Messages
80
Hi i have got may hands on a KE-7 just as a motor that i can put on a sea flea probably a tiny titan, although i wanted a kg-7 i haven't found one at a reasonable price here in Canada in two years of looking so i settled for a e, i know i wont get the insane rpms out of it however i want the old fifty's racing look and SOUND so id like a pair of what i believe were called megaphones back in the day.ConvergingPipes.jpg I don't know much about outboards of this age but i don't want to lose power, i don't really care if i gain much. if the exhaust is just going out a port in the leg there should be very little back presser and further more with my understanding of how a 2 stroke works i cant see how much back pressure would effect it. unless somebody knows of a website that sells them, it looks like all be fabricating a pair myself. Hers where the questions start! the plate that the stacks attach to will obviously be a flat piece of steel, but how thin of a ice of steel can i use without it warping in the heat? the next part is the stacks, im really going at this without a clue of what im doing mainly because there is no real reading on this type of thing on the internet. i imagine you could create some amount of back pressure by the diameter of pipe used in the stacks, but what diameter pipe is ideal? this is the part where im relying totally on your input, i have the tools and the skills to make them i just dont have anny real clue where to start. any thing helps. Thanks!
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: Mercury KE-7 tuned pipes

I wouldn't bother with the pipes - why annoy the neighbors? Also a sure way to get the water cops after you. Plus, on a service motor, all they'll likely add is noise. Not saying you can't, just that I wouldn't...

If you really do want to go ahead with something for the plate, most that I've seen have been 1/4" plate steel with the elbows and pipes welded to it. The pipes are usually just sheet steel, rolled to shape and welded up. Some are welded to the base, others are clipped with springs. You also need to fabricate what is called a filler block to divert the exhaust into the pipes and prevent water from getting into the exhaust. Most of the ones I've seen have been two into one pipes. The 2-pipe ones are much less common.

You can also make some noise by modifying the leg - many folks have cut the rear of the exhaust snout off to make it more like the Quicksilver tower housing. Lots of info out there on Mercury Rat Racer motors, .ie service motors that have been hopped up in various ways. Check into JohnsOldMercurySite.com, too.
 

ryan 98

Petty Officer 3rd Class
Joined
Jun 23, 2013
Messages
80
Re: Mercury KE-7 tuned pipes

thanks, the pipes are cool even if they are just bolted over the existing plate to give it a cool look. however where i run the boat i shouldn't bug any neighbors, and in 5 years have only seen the police cruiser once. so all get on this and see if i cant get a set made. the quick silver leg is verry cool but as i undrestand the going rate for one is around $1300 so i think all just put the pipes because ive always wanted a motor with the pipes on it. Thanks for the advise and telling me about the filter block id have never known about it.
 
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