exhaust riser and manifold for mark 2 1997

[captran]

A mechanic came aboard to look at one thing, but also poked around a bit (I'm sure that will cost extra), Said something was loose, and when checking near the top of the riser, there's a hose with a clamp and the clamp was broken.  Installed new clamp and no more wobble/looseness.

[Jon W]

If it's leaking, it should be replaced. Depending on where the crack is, you could be leaking carbon monoxide into the cabin.

I have a 1987 MK 1. Each boat and vintage seems to be a little different, so the following is just a reference point for you.

I replaced the hose from the exhaust riser to the Aqualift muffler with a Trident silicone "hump" hose.

To do that I prepped the area to get access to everything. The steps were remove coolant, loosen the hose clamps, remove the riser, clean off the old gasket, remove the old hose, check Aqualift muffler for cracks, install the new "hump" hose, reinstall the riser with new gasket and sealant, add coolant, bleed coolant system. Time to do all of that was about 1 hour.

Does his 24-32 hour estimate include making a new riser? When you do this I highly recommend installing a "hump" hose instead of the standard exhaust hose. Really helps dampen engine vibration.

[KWKloeber]

exhaust manifold adaptor ... leaking exhaust. 

Randy

I presume he's referring to the exhaust flange?  (removing and fixing the leak, presumably could be as "easy" as a new gasket.)
 
The unfortunate reality is that the vast majority of time/effort/lost skin on knuckles/cost is getting the old parts apart w/o ruining them (if that's even possible,) and if new studs are needed and/or if the flange can be reused or needs replacing -- so that simply fixing that leak and not replacing the whole shebang seems a waste.  e.g., How many years will it be before the riser needs to be replaced (if indeed it's only rusty and not about to fail.)  Make sure the new gasket goes on facing correctly -- on backward, you dump all your coolant out the exhaust (and need to start all over.)

-ken

[Ron Hill]

Randy : I believe that Ken is correct.  If it is the Gasket between the exhaust flange and the exhaust manifold all you need is a $5 gasket!!

Can't recall when Gerry Douglas said the hump hose was standard C34 MKII production - thought it was with the first MKII hull # 1295?

A few thoughts

[Jon W]

Randy, if Ron's memory is correct your number boat should have a silicone "hump" hose installed. If it were me I would put in a new silicone "hump" hose. The boat is 23 years old, and if you're removing the exhaust riser for repairs, it's a perfect time to also change that hose and check the Aqualift muffler for cracks. Then you know that system is good for a long time.

[Stu Jackson]

The hump hose connects from the end of the exhaust riser to the muffler.

[Noah]

This is a hump hose:
Disregard the rust. Been cleaned up since photo.

[Jon W]

To avoid any cornfusion, the blue hose is the "hump" hose. 

[Ron Hill]

Guys : The MKII C34 has a different muffler that that of a C34 MKI. 
That hump hose is fairly resilient and I'd call Tri Dent and ask them about the life span of their hump hose.

A few thoughts

[KWKloeber]

I just don't know enough to know what to look for.

Rsndy

if you mean for the leak itself, you can usually tell/locate an exhaust leak w/ her running.  If you puff some baby powder around there you might see a telltale exhaust leak blowing it.

If you mean generally, you need to unwrap it, and start poking the bear to determine if it's all competent pipe or corroded/thinning.  If you whack at it and it's competent it shouldn't dent (heavy pipe.) 

A screwdriver or heavy icepick will tell you if you can puncture the riser anywhere or if it's about "to go."  Or tap on it w/ a small ball pein hammer to locate weal spots (sound different) 

Elbows and the water injection wye are typical fail points.

[KWKloeber]

As Capt Ron said, different muffler.  Side in, (right angle) top out.
It still would not hurt (opinion) to use a silicone hose on the inlet side - more flex and less probe to transmitting vibration. Or a non-wire-wound exhaust hose or corrugated exhaust hose.

[Ron Hill]

Randy : Absolutely get a silicone hump hose between that riser and the inlet to the aqua Lift muffler.
Like I said I thought that Gerry Douglas told me that the MKIIs had them installed.  Must be later production than yours?

A few thoughts