Shotgun Muffler Noise
 

Has anyone noticed a funny sound from these mufflers whenever you change throttle position.Mine make a noise that sounds like a bad missfire(or a 30 year old VW bug) but goes away after a few seconds.If you look over the transom you can see them fluttering like crazy.I moved the ram to the middle position from the lightest position and it got worse.I'm going to pull the mufflers until I get the boat set up.

That's how they work, the flaps are spring loaded and at idle they're working against the exht. pressure trying to close. You can also loosen the allen key on the flapper shaft to give even less tension then they won't be flapping closed as much .

I had a similar thing with mine. I called Drew and was told that if you have ANY miss that the Shotguns will amplifly them big-time. He said to look for the miss. I finally found it was a lean condition. In the mean time I set the flappers to the lightest setting and set the flappers to be open 1/8" with the engine off. This solved the sound. A little louder at idle but not much. I set them back after I fixed the miss and everything was fine.

BH

Re: Shotgun Muffler Noise
 

I discovred that my flapping noise was wosre with over jetting.As I was working the jets down the noise went away.I ran it for a few months this way and they seemed good as long as you didn't increase the spring tension on the arm.Now about a week ago the flaping noise came back.I leaned her out a bit more thinking the summer heat maybe richened it up a bit but it made no difference.If you idle it at the warf they fluter consistantly but if you bring the RPM up at about 3000 they fluter eraticaly and the noise appears.They move freely but maybe the springs have worn a bit.I grabbed a couple of sticks off the beach and jammed them in the buterflies to hold them open and the motor sounded great.Are you guys having these noise issues.I am going to set the butterly open a bit and see if this helps.I can't stand having a decent motor that sounds like crap.Maybe I sould turf the shotguns on put some bolt on mufflers on.

Re: Shotgun Muffler Noise
 

I would call Drew. He is easy to get ahold of. He probally will be the one who answers the phone...The flappers work on exhaust pressure. If you have a miss in your motor (decrease in exhaust pressure) the flappers will amplifiy this noise...I had a lean miss and thats how I found it out....It was annoying though. But once I fixed the lean miss it was gone....Now as far as a "flapping" noise I haven't heard this on mine. But the flapping noise could only happen when the butterfly hits the stops in the muffler itself. I would loosen the butterfly and tighten it so that it stops just before it hits the stops...This should take care of the exhaust bringing out the miss and should stop any flapping noise. I would use some loc-tite to help keep it snug. Since I found my miss I went back to the normal setup and haven't had any problems....I will try and find a pic of how I set them up when I had the lean miss.

BH

Re: Shotgun Muffler Noise
 

Hear is the pic of the flappers. I set them with the butterfly just slightly open. Took care of my miss "sound" but not the miss (which was in the carb). I only got the "miss sound" when I was at cruise between 3200-3800. Anyways miss is fixed now and shotguns are set back to stock.

BH

Re: Shotgun Muffler Noise
 

I set the butterflies to be open about 1/8 before the stop and it sounds fine now.

Re: Shotgun Muffler Noise
 

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