Briggs & Stratton - noise & vibration update

[RRitt]

I can't find the original thread where exhaust noise was discussed at length. I finally got around to extending the exhaust and putting the 5HP Briggs on my squareback canoe. It works great. After extending the exhaust about 4" under the water the engine noise is about the same as any small 2stroke. If you have a briggs and want to tone down the noise - then this is a five star modification.

There is no need to take engine apart. It all just adds onto the existing and can be put on or taken off as desired. Use a 1/2" copper street elbow, about 30" of 1/2" copper tubing, a radiator clamp, and a very small length of muffler tape. I used mechanics wire to tie copper tubing tight to gearcase. I will eventually use stainless hose clamps to secure copper tubing (this is a saltwater engine).

Having finished this project I would say 2 things.
1) IMO, the briggs is the best small outboard made. I don't plan on having a sissy motor and avoiding the saltwater shallows. If the water is deep enough to be shiny then it's deep enough for me to go hunt for some fish holes and crabs. Air-cooled 4stroke is awesome. This engine will still be running long after all the others would become junk. No more impellers to replace, no more gas to mix, no more ethanol blues.

2) This engine is too big for my ganoe. 20-25MPH in a canoe is just not safe. I think the briggs needs a 10-14 ft jon.

 

[mrcrabs]

Re: Briggs & Stratton - noise & vibration update

IMO, the briggs is the best small outboard made

Its well known that briggs and stratton major success was the dummy proof ignition timing, like wise tecumsehs major failing was there advanced tuning features, ignition and carb...delbert just could not tinker with them and keep them cutting grass.

so RRitt you BS turns what 3500 rpm? and you go 20-25 mph amazing!

I guess you got her geared right.

the AV 817 Tecumseh is rated at 7.5 hp turning 5650 rpm,(all needle bearings of course) I bet your canoe would exceed 50 mph with a Eska compared to that lazy old BS...

 

[GLENN M]

Re: Briggs & Stratton - noise & vibration update

ive never seen,or heard of a bs outboard would love to see a picture.and if possible one of your canoe doing speed trials.thanks

 

[RRitt]

Re: Briggs & Stratton - noise & vibration update

Its well known that briggs and stratton major success was the dummy proof ignition timing, like wise tecumsehs major failing was there advanced tuning features, ignition and carb...delbert just could not tinker with them and keep them cutting grass.

so RRitt you BS turns what 3500 rpm? and you go 20-25 mph amazing!

I guess you got her geared right.

the AV 817 Tecumseh is rated at 7.5 hp turning 5650 rpm,(all needle bearings of course) I bet your canoe would exceed 50 mph with a Eska compared to that lazy old BS...

I think I could change the prop and slow it down. It was idling around 5Mph.
also, i think the 5hp is rated at prop. I wouldn't be surprised if it was a 6.5hp block.
But - the real lesson I learned is that putting a 5hp motor on a 14ft canoe is a dumb idea.
Like rocket roller skates. Some things just aren't safe in the real world.

 

[RRitt]

Re: Briggs & Stratton - noise & vibration update

ive never seen,or heard of a bs outboard would love to see a picture.and if possible one of your canoe doing speed trials.thanks

I have already abandoned the project. It was not safe. You can find you tube videos of guys having fun in the mud with them. B&S was never about speed. It was about running into salty mangrove bottom and not dying. Regular outboards have to go to the shop and get new impellers every time they suck up bottom around here.

the important thing of this thread is not speed or whether or how big an engine that you can put into a canoe. The important thing is that you can put 30" of tube on the end of a briggs exhaust and make the engine quiet. It does not become hard to start, run rough, overheat, or have excessive vibration as so many outboard people predicted. It runs just fine. It is as quiet as my little mercury 2strokes and doesn't really vibrate that much more than other one cylinders. the BS throttle is linear whereas the little marine jobs seemed to have finer control in the midrange. But given the thousands of dollars I have spent on impellers and the size of the 2stroke graveyard (aka the ethanol altar) in my garage ... i'll take air cooled 4 stroke any day. The combination of quiet plus air cooled makes it the perfect jon boat motor for shallow bottom boaters.

 

[mrcrabs]

Re: Briggs & Stratton - noise & vibration update

thousands of dollars I have spent on impellers

you should have bought a air boat with all those thousands,...lol

ethanol altar

use some thousands to buy ethanol resistant fuel lines like everybody else does.

But your modification could be against the law, (coast guard regulations ya know) I know that in Illinois waters you cannot legally modify the exhaust on outboards and frankin motors will get you plenty of attention from the coast guard in the rivers, if you live in a state that requires titles to the outboards you may as well forget modification...all that being said congrats on your modification....how ever I would wager that a thermal heat gun would show a significant rise in the temp of the exhaust valve area compared to non modified engine since any addition to back pressure will increase the overall temp of a running motor, I think the only saving grace is while underway there should be a decrease in exhaust pressure...its at Idle that you start heating things up.
This is why thru hull exhaust on inboards will increase preformance and longevity of the engine.

thru hull exhaust also kills less kids since they don't want to set back there by the noisy stinking exhaust.

 

[RRitt]

Re: Briggs & Stratton - noise & vibration update

Yeah, they charge $250+ per engine for an impeller around here. Mostly labor.

You just don't seem to understand McCrabs. Most of the water around here is too shallow for water cooled engines and the bottom is a mixture of sand, oyster shells, and muck. It is instant death for water pumps. Thats why they invented airboats. Have you ever ridden in an airboat? They are very unpleasant. Air cooled outboards give you a way to go into airboat territory without having to use an airboat.

 

[tx1961whaler]

Re: Briggs & Stratton - noise & vibration update

They sell Gheenoe's down there in Ft. Myers/Punta Gorda. They can handle a larger motor and skinny water.
http://www.gheenoe.net

 

[mrcrabs]

Re: Briggs & Stratton - noise & vibration update

I have ridden in a airboat lots and agree there beasts, my wife is a Miami girl and I have spent a fair amount of time in the glades...and I'm just given you a hard time for sh!ts and grins, Have a great new year and don't tear up that old BS....lol and hey I love my 23hp BS mower and even got 75$ coming from a class action law suit over the hp rating thing....now where is my check? I need some Eska parts....

happy new year

 

[RRitt]

Re: Briggs & Stratton - noise & vibration update

They sell Gheenoe's down there in Ft. Myers/Punta Gorda. They can handle a larger motor and skinny water.
http://www.gheenoe.net

I went to the fort myers basspro superstore today to buy either a new engine or a new boat. According the the various experts in bass pro:

The best boat to fit a 5HP outboard is a 14 ft jon. The 12 would work but 5hp might be a little much in certain conditions. The 14ft old towne flatback canoe is rated at 4hp. The salesman advised that it should not be used with anything larger than 2.5HP. He said larger engines can become unsafe at full throttle. A 60lb thrust trolling motor is equal to 1HP. Outboards engines should not be operated in less than 18" of water. When the water gets shallow, turn them off and use a trolling motor.

At any rate, the idea of turning a square back canoe into a gas powered mud boat is a dead end. They don't make a mud motor small enough. I would have just bought a jonboat for my briggs and been done with it except for one thing. While I was in the kayak department I saw an Old Towne canoe that called out to be. I want that boat. It is the most perfect boat for me I have seen in years. It has an insulated beer holder molded into the seat! I can exercise, fish, and drink beer all at the same time. And it fits into the back of my pickup truck! Thank you Jesus!

So I walked away with a 30" shaft minnkota trolling motor. Tommorrow I test to see how many batteries I will need to buy. Then I go back and buy myself a new canoe.

 

[steelespike]

Re: Briggs & Stratton - noise & vibration update

I'm sure the canoe isn't making 20-25 but I bet its spooky wide open with a 5.
If you want to see a briggs on the water look on youtube.you'll find real ones as well as home made.

 

[mrcrabs]

Re: Briggs & Stratton - noise & vibration update

what about the outboard jets they use in the sandy shallow waters over in southeast missouri,

http://www.outboardjets.com/index.php

http://www.youtube.com/watch?v=3GEkMb3fcnQ&NR=1

 

[RRitt]

Re: Briggs & Stratton - noise & vibration update

I'm sure the canoe isn't making 20-25 but I bet its spooky wide open with a 5.
If you want to see a briggs on the water look on youtube.you'll find real ones as well as home made.

I think it depends upon the boat. My canoe is real skinny and cigar shaped. A lot of squareback canoes are rectangular for stability.

 

[RRitt]

Re: Briggs & Stratton - noise & vibration update

what about the outboard jets they use in the sandy shallow waters over in southeast missouri,

http://www.outboardjets.com/index.php

http://www.youtube.com/watch?v=3GEkMb3fcnQ&NR=1

why bother? throw $4 worth of copper tubing on the briggs and its an awesome little mud motor. Cheap, reliable, and no noisier than a 2 stroke. you probably should not beat on it with a baseball bat while its running but otherwise that's about it. Don't even bother changing the oil or tuning it up. Just run it until it dies then go buy a whole new powerhead for $130. It doesn't even need water. you can run it for hours on a sawhorse.

What more do you want?

 

[mrcrabs]

Re: Briggs & Stratton - noise & vibration update

What more do you want?

at my advanced age speed is handy....lol