Logo
FULL SITE MENU

Replacing exhaust risers on b67 318

B

bearhair

New member
"Hey guys, Im about to change

"Hey guys, Im about to change at least one of the risers on my 318. I was wondering if it is as easy as it looks like it should be? Is there any important info. I should be aware of? I just planned on buying the riser and gasket set and swapping them out. Thanks."
 
"If it's the non-adjustabl

"If it's the non-adjustable side, it's pretty straight forward--but be sure to drain the system FIRST (including the block IF you have raw water cooling).

If it's the adjustable elbow that can swing for adjustment, this is tricky. THere are O-rings inside there that need to be lubed and treated very carefully, and the bolt hiding under/ inside is a dog to work with--I had to make a special box wrench to work it. Note: This riser/ elbow needs to be replaced as a unit.

Jeff"
 
"Ok, thanks Jeff. I'm comp

"Ok, thanks Jeff. I'm completely new to this whole thing. I have a heat exchanger which I think means that I don't have raw water cooling. Have you seen a diagram or photo of this (riser) part of the engine anywhere online? I'd love to see a pic of the "riser/elbow" and I'm having a hard time visualizing any adjusting on this part but there is definitely at least one bolt on the underside (that's where the riser corroded and broke away). Thanks."
 
"Sam, I just went through wha

"Sam, I just went through what you're doing. If I were you, I would also replace the exhaust manifolds and the elbows also. If your risers are rotting out, your manifolds are probably ready to go also. Better to do it now, than having sea water get into your cylinders from a rotted out manifold. It might be a little pricey, but better than ripping your motor apart due to rusted out cylinders. Try boatfix.com, excellent prices and there are pics of the parts you need."
 
"After re-reading your post, I

"After re-reading your post, I think you have the old style 318 'Polyshperical' motor. If so, finding parts for it will be very difficult.

Am I correct in this?

Jeff"
 
"Sam What model 318 LM or M T

"Sam What model 318 LM or M The LM has 5 bolts holding the valve covers on and the M has only 2.

We have LM and all the parts necessary, and on the M318 I do have a source for those also now. Email me at [email protected] if I can help

Dave"
 
"Hey Guys, thanks so much for

"Hey Guys, thanks so much for your responses. Sorry I've been out of town for the last few days. It is the LM. So you think I should replace the risers, elbows and manifolds? Sounds spendy but seems like it will save money in the long run. On a scale of 1-5 what would you rate the difficulty of this repair. I know my way around an engine but have never worked on a marine engine at all. My neighbor told me that all I would have to do is drain the coolant below the manifold. That info seemed a little to simplistic to me but I don't know. Thanks again guy's, I really appreciate your time."
 
"Sam, if your manifolds are r

"Sam, if your manifolds are raw water cooled, just disconnect the risers and elbows from the manifolds, they have 4 bolts each, hopefully not too corroded. then there are 6 nuts, and studs under the manifold that connect it to the block, just remove the manifold and clean all gasket surfaces on the block and the new parts, and re assemble. Hopefully the nuts and bolts were stainless, or you might have a problem with corrosion. after re assembly, run the motor for a while, then re torque all the nuts and bolts. Its not difficult at all, pretty self explanitory. On my motor, I got new everything for both sides, and with shipping it was about 700$, lotta money, but it will be good for at least 5 more yrs. As for draining, there are plugs on the bottom of the manifold, but you shouldn't have to if the motor tilts back enough. Good luck. Ps, if the nuts and bolts are not stainless, get the stainless mounting kits, will save big headaches years down the line."
 
Back
Top