Merc 454 owners manual.

[Sea Daze]

Hello All,
Can anyone tell me where I can download for free the manual for the merc 454 I/O

I need to change the manifolds, and wanted to see if its a DIY job. Mechanic wants $600.00 just for labor to replace both manifolds.. Is this something that I can do myself?

 

[Presentation]

Hello All,
Can anyone tell me where I can download for free the manual for the merc 454 I/O

I need to change the manifolds, and wanted to see if its a DIY job. Mechanic wants $600.00 just for labor to replace both manifolds.. Is this something that I can do myself?

The information you are seeking is not in the owner’s manual.

You need an engine serviced manual + basic mechanical knowledge.

I have this for my engine but not your engine.


Many people do this as a DIY do it yourself project. It’s at the more advance side of DIY versus a oil and oil filter change is at the more novice side of DIY.

Difficulty would be on par with a drive bellows change however a manifold job would take more hours.

 

[Fun Times]

We would need your engine serial number to help you find the correct service manual for your engine. It appears like Mercruiser may have had two service manuals to choose from around your boat's time frame of 1993.:smt001

 

[Air O'Nautical]

This is a question you need to ask yourself if you are capable of....experience and tools???
Ever done similar type work??

The hard part of this job is removing the old manifolds.
Access can be a PITA. Working with mirror and shop light so you can see the manifold bolts.
The bolts maybe hard to remove or snap from rust.
Sometimes hammering on a smaller size socket will work.

Once removed it easy to install new.
If you are up for it, all the info needed is available thru this site's kind people.

Good luck,

Mark.

 

[Ka1oxd]

I just did it on my 454 inboards. The process is not hard, but is going to take more time than you think. I got the manifolds and risers from Partsman http://www.marineengineparts.com/. They are very knowledgeable and will help you. Parts came in a couple of days. The process is spray the bolts with PB blaster the week before you do it. It takes a 9/16 socket wrench to take off the 4 bolts to the riser. Then take the 8 bolts off of the manifolds. Make sure that all the hoses are off first. When you take the 4 long bolts off from the riser, keep them near you since I used them in the manifold once I had 2 bolts out. I put them in a few turns by hand, then proceeded to remove the rest. If all works right, when you undo the last manifold bolt the manifold will slide down the long bolts you put it.

This is really about if you have faith in what you can do. It was the first time I did this and it went well. I am going to do the port engine this fall. I should have it done in a day with tricks that I learned from the first ones.

The key is if you can get enough penetration oil on the bolts. That was my biggest fear is that when I went to loosen them after 22 years, that they would snap then cause more work. Each one broke free without problems. When I put it back together, I used anti-seize on the bolts, just a habit of mine when 30 years ago when I was a tool and die maker.

 

[Sea Daze]

Thanks guys for the post.. I watched a video on youtube, and the process does seem to be simple.. Like you said its just a matter of getting those old rusted bolts out without breaking them.. Also thanks for the link.. Great help..

Question what is the normal running temp for the 454 at around 3.5 or 4K RPM??

 

[out-n-aboat]

I have the service book,
pm me your address and 20 bucks plus shipping its yours.

 

[sam]

It is not a bad price it takes around 8 hours per engine if you don't break anything.

 

[tdschafer]

Question what is the normal running temp for the 454 at around 3.5 or 4K RPM??

My 454's run at 170 degrees regardless of the rpms.