Mercruiser 7.4L Exhaust Manifold and Risers

[jman32]

It is common to replace the exhaust manifold when changing out the risers? I have my Maxum 3700 in Marine max for repairs and I just want to know if this practice is common and how many hours does it take to complete the job. They have quoted me 8 hours to change out the manifolds and riser on both engines. Please advise. R/JM

[seapuppy]

well..it depends on how much corrosion there is...if it's just the risers that are affected..then those will be the only things to replace..however..if there is damage to both..then yeah..I can see it..especially if the boat is used in salt water...

as for how long it takes....it's reasonable for one mechanic to take all day to replace 4 manifolds and risers....and on big block engines...they aren't light..that's for sure...so....I could see him taking a full day to replace all 4...I know I'd be huffing and puffing trying to lift those monsters...

SP

[jman32]

I do need to state that I just bought my 1998 Maxum 3700 SCR as part of an estate sale. Very few maintenance records were provided to me prior or after the sale. Both engines worked perfectly at the close of the sale. I guess a little personal background information is in order. I'm a retired Navy SEAL Commander and spent most of my life on or around boats and ships. I have some background in outboard engines but very little exposure with inboards.

Anyway, I made a trip over to Marinemax yesterday and looked at the engine and parts on the maintenance floor. The mechanic was great and showed me the issues with my manifolds, risers and elbows. I agreed with his assessment and actually requested to have the heat exchangers flushed out and painted also. I was nice to see the engine on the floor to really grasp the exact condition of the powerplant. I should be good to go after everything is completed. I just need to calm the wife down after she saw how much it was going to costs us to get the job done.

[seapuppy]

John,
welcome to the zoo....Seal eh!!...thanks for your service to the US and the United States Navy,
me...I'm no seal by any stretch of the imagination but I did sleep in a holiday inn extended stay once!!...ok...actually ...I spent 17 yrs designing nuke subs and some surface combat ships....my last boat was the 21 class subs...we kept you guys in mind when we designed her..... :wink:
also raised a navy brat....dad was on destroyers most of his career...we did have a stint at Little creek once....spent most of our time up in norfolk.....


anyway....glad you got to see everything on the exhaust system...keep them maintained and flushed after every use in salt water and everything will be good for yrs to come....as you know...good maintenance key to safe boating....

plus BOAT = BREAK OUT ANOTHER THOUSAND

keep those cards and letters coming!!..
SP