exhaust hose 85 nautique

I was wondering what size diameter exhaust hose i needed for an 85 nautique with the 351 ford engine. It has a 3" exhaust riser outlet, does this mean 3" id hose or bigger? I have noticed you can go many different sizes, ie 3, 3 1/4, 3 1/2 etc.

3 inch, make sure you buy the right hose, Make sure!!!!

rhschnauss wrote: 3" corrugated right? I almost bought hardwall.

You need the corrugated if you have a bend to make, but either way you need wire reinforced wet marine exhaust hose. You probably already knew that, but the cheap stuff can burn through and sink your baby!

has anyone done the section uder the gas tank. I think I can do it without taking out the gas tank, but im not sure. any ideas.

JoeinNY wrote: It can be done from the front but it sucks

It does...knees, nuckles, and neck! LOL

(just for you John?!!?)   ROFL

Well. I got all working right after my exhaust manifold leak and the top end rebuild... except my exhaust hoses have both sprung several leaks and it appears the only way to get the hoses out is to take up the back section of the floor.. as one of the mufflers is damaged.

anyone have any project advise?

Sounds good.
The only way to get the mufflers out appears to be either take up (cut) the floor or smash them (mufflers) to pieces as they will not make it through the small outlet by the engine. Any advise?

So, you suggest db's --- is that double wall pipe? What is the best way to join the db's w the bending corrarated pipe? I suppose skidim is the best way to go?

---

Thanks for all your help 8122 as you have been there this during this entire episode!

Famous last quote of mine before I bought the boat: " the last thing I want is a project boat as I have 2 already."

Well, I guesse I am vexed.

Cheers for the wicked.
jamie

pete,
was the 83 also fiberglass. There is a noticeable difference between the sound of my dad's 83 vs my 86. I replaced the exhaust hose on the starboard side and mine ran into the fiberglass. Are you saying when you change it to run the corrugated pipe all the way out to the exhaust tips?

P.S. Changing that small section was also a PITA. Can't imagine the whole run!

shawnmc wrote: There is a noticeable difference between the sound of my dad's 83 vs my 86.

I'd like to hear some more about that if you don't mind. One of the boats has the glass mufflers and one doesn't? Which one bothers the neighbors?

Yeah I agree, lose the mufflers. Mine were pretty banged up so I tossed them and ran pipe the whole length. It actually picked up almost 4 m.ph. on the top end! It is louder but only noticable when going fast. At idle when the tips are underwater there is no difference. Sounds awesome, Dozi's eat yer heart out!

the whole center sectin of the floor behind the motor box should lift up and out once you remove the screws holding it dwon. the heads to the screws will be burried in the carpet and you may not see tham and have to feel for them. But lift the motor box and you should be able to see where the floor is split right on top of the stringers behind the motor because it came from the factory that way now if someone has replaced the floor and did it not orginal then you might have issues but I doubt it is done that way you are just not looking close enough but the floor comes out from the rear of the motor all the way back to gas tank. Might have to lift the carpet up, might have to cut the seems if it's been replaced and done as one piece look where i told you for the seem in the floor at the back of the motor and you'll see what I am talking about.

thanks.

the floor is one piece. PO did a good job.
no seams - must cut. here we go.

Jamie, I would stay away from the aluminum. Unless anodized, you would be seeing lots of corrosion. (white rust) Repair the existing mufflers (you won't find new that will fit) or run hose all the way.

Jamie, If you can't make the bend with the hose (corrugated hose has a tighter bend radius than hard wall but is slightly more restrictive), then you may need elbows. Double hose clamps for the connections. What hose was in it making the bend? Skidim may not have the corrugated.

TRBenj wrote: Pete, what do you mean by this? 8122pbrainard wrote: corrugated hose has a tighter bend radius than hard wall but is slightly more restrictive Are you referring only to a tight bend radius being more restrictive than a larger one?

Tim, It's the slight corrugations on the inside of the hose. The hard wall has a smooth ID. The restriction is slight but if you look at the flow/pressure charts it is there.

Although a lot less pressure, a good example of this, is the flex heat ducting you are finding these days (it's cheap and quick). To get the same volume of air at the same static pressure through the flex, you need to go one size larger dia. than using galv. ducting.