Are most of you using external flappers on your boats? The engine builder said that I really didn't need any, but there no internal flappers either. I know that I have a drop from the headers to where the tails exit, but was wondering if any externals are needed? Such as when backing off of a trailer, boat wakes, coming off plane, etc. They certainly look better without flappers, but just trying head of any potential trouble. Thanks.

I have both internal and external flappers.
Cheap insurance. But then my boat sits real low.

How will I know if I'm getting water through the exhaust? Will this shut the motor down, or will it just get worse over time?

They are there for a reason, and without them you are taking a big risk of water entering the pipes and possibly the engine. One wave into the transom and you could have water in your engine, not so much while running, but while not running there is nothing to stop the water. Even with the engine running,if in reverse, you are at risk. Most factory set ups have both the internal and external. The exception would be a boat set up with some type of external muffler system, here the muffler takes the place of the flapper with the internal baffles acting as the water stop. I have even seen some muffler set ups with the flappers as well. Protect those new engines you have, besides on a 35 Fountain you'll never see them other than on the trailer. If you want the best of both worlds buy the Drew Marine Shotgun Silencers, polished stainless looks real good, and the silencer baffle acts like a flapper, also takes the bark out at low speeds then fully open at WOT for no power loss. Ran them on my last boat with 525 SC's at 600+ hp with no loss of performance at all, real nice set up.

To answer your last question, you will know real quick if you get enough in the engine, you can hydraulic lock the engine, it won't turn over and in the worse case,if it does start, you can bend rods and break chit. Run the flappers, convince yourself that even though they look ugly, they do a real cool job of protecting those big buck motors you have in there. Or just don't look when the boat is on the trailer.No matter how much drop you have in the tail pipes water can still get up in there, once it does you have a real mess.

Appreciate the comments Ragged Edge. I'll be sure to order at least the external flappers. Haven't convinced myself that I need mufflers, yet. Probably, haven't had enough run time on it!

Do you know, does Trick Marine carry the external mufflers? If so, what's the best way to get ahold of them? Thanks.

VA law actually requires them, also they don't hurt performance, its not worth the chance of water reversion.

WILL

I ordered mine from Teague today. Thanks.

The Drew Marine Shotguns can be ordered direct from Drew Marine for $460.00 per pair, current ad in Hot Boat Mag, @509-535-3393, see them @ www.drewmarine.com

I'll keep those in mind. Thanks.

Is that what you are running? If so, how are they working for you?

Not on the Fountain, it has the silent choice set up. I did run them on my last boat with Merc 525 SC's w/intercoolers and boost upped @625+ hp and the worked very well, reduced the noise and never cost me any speed at all. I would buy them again over any other silencer I have seen.