Exhaust risers do it yourself??

Panchita

New Member
Jan 24, 2009
48
MIAMI
Boat Info
2005 340 DA
Blue hull
Garmin 740s with Radar
Engines
8.1 Merc V-Drives
I am mechanically inclined and am wondering if it is worth it to replace all riser , exhaust manifolds etc as a do it yourself?

Has anyone attempted this as a DIY?
 
It is an easy job! I would not pay anyone to do it if you have the tools. If not invest in them, should be an 2 hour job tops per engine. Make sure you clean gasket seats well and you should be all set. 8 bolts or so per side for the riser/manifold less the shifter assembly etc. Go for it!:smt038
 
yea,, marine max quotes $5400.00 all in for the two engines!!
Crazy,,
 
Do some research into the correct gaskets to use. Maybe one of the Technical Advisors can chime in there. After my engine survey, my mechanic told me what to use but I don't remember...
 
Absolutely a DIY job. Just be prepared to lift some HEAVY metal up and out of the engine bay. Lay down some protective coverings on the surfaces so you don't scratch up the gel. Good luck and let us know how it goes.
 
yea,, marine max quotes $5400.00 all in for the two engines!!
Crazy,,

Shooting from the hip the cost of parts alone are probably in the $4500-4800 range for 2 engines. An 8 hour day to install will make up the difference.
 
It's just nuts and bolts - IF the bolts come out. With a newer boat you should have no problems. I encountered 4 severely rusted in bolts and one with a rounded head. Keep in mind these were likely 20 seasons in place.

You have risers, elbows and manifolds - if you go all OEM parts, the total parts bill should be ~$1800-$2000.
 
Last edited:
Shooting from the hip the cost of parts alone are probably in the $4500-4800 range for 2 engines. An 8 hour day to install will make up the difference.

For 2 new engines maybe but not for 2 manifolds is it? :huh:
 
I've done it. Not hard. You need a torque wrench to properly refasten bolts. A trick I've read about is to replace a few of the manifold bolts with "headless" bolts during removal and install. They align the bolt holes and hold the heavy manifold in place as well as the gasket.
 
4.3's in a 280 da is a tight fit and will be a pain in the butt. first start with unscrewing your back seat, then unhook your hatch pistons and tie your engine hatch straight up. this will give you more working room. The flatrate on doing both engines from mercruiser is 7.4 hours. If MM miami is more in labor Talk to Bruce LaPorta he is the service manager there. I know him very very well.
 
quint4 was talking about the headless bolt which is an awsome idea, but it won't work for you since your engines are so close together and the bolts you would need would be to long. that trick works great for the big block engines (7.4) since the bolts holding a 7.4 manifold on are only about 1 1/2 long. Small block and V6 are a few inches long ( around 4-5)
 
Thanks..

Bruce quoted the job,,, just under 1000 for labor,, 4000 parts, 350 tax.

Yes it is a tight fit and the reason I do not like to work on the boat,, as it takes a small very flexible person to do this with relative ease,,,

I suppose I can save 1-20% on parts and will probably take me two days of work,, so what is my time worth etc,,,
 
No matter what brand you replace the manifolds with... use the oem Merc gaskets. I have had lots of problems with the cheaper ones, but never with the merc's. Are your engines fresh water cooled?
 
my boat is salt water cooled, so this will be the third set in almost 7 years,, preventative maint,,
 
flflatrate:

Have you ever replaced the Water heater on the 280?
 
For 2 new engines maybe but not for 2 manifolds is it? :huh:

Uh no. I was quoted $2100 for a set of manifolds and risers, gasket kits etc, for my 5.7L. This was for the newer style dry fit ones.

If you find 2 new engines for <$5k buy them.
 
clarification , the price is for risers, elbows , labor etc for two engines,,
 


7B Complete V-6 Exhaust kit (4" Elbow)

mv64set.jpg
Fits mercruiser V-6 models Inc gasketsCast iorn ConstructionREF # 58222

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[/SIZE]Your discounted price: $464.95 plus S&H
[SIZE=+1](800) 349-2628 ... (504) 888-2798 ... Fax (504) 888-2881[/SIZE] Here are some aftermarket parts, I believe they are GLM or osco. I put them on my new engines 4 years ago with no issues. I can't see Merc parts being that much more? Do I have the correct parts listed for your engine? If you are changing them every 3 years I would not hesitate to use them. Merc gaskets are a good idea. They make a 3 and 4". Any comments? I use these guys all the time for most parts and have never had a problem. But then again I don't take my car to the dealer for the expensive parts either. :huh:
 

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