Old 04-08-2015, 06:06 AM
Admirals Club Admiral's Club Member
Join Date: Sep 2009
Location: Gloucester, Ma
Posts: 1,185
Received 39 Likes on 34 Posts
Default Riser - life expectancy in the North East. FWC Merc 350 Mag 5.7l

I was curious if there is any change to the serviceable life expectancy of risers on a FWC engine in the North East opposed to other areas in the country. 5-7 years of service seems to be the norm with inspections and gasket replacements every 2-3 season.

  • Water temperature is colder, about 60-65 deg average surface temp.
  • Boat lives in salt water for 4-5 months a year.
  • After pulling it is flushed with fresh water and eventually winterized with marine antifreeze and left untouched for 6+ months.
  • Dry joint exhaust/ risers (not sure if it makes a difference)

I purchased this boat last year and know the previous owner and the history. Engines were new in 2009 and the boat did not make it to the water in 2011. So the risers have really only been used for 4 seasons. Engines have less than 200 hours. Merc 350 MAG MPI's 5.7l. I have had a boat on the same dock since 2004 and am 100% confident in the accuracy of the statements above.

The engines run great and oil did not appear to have any salt water intrusion end of last season.

During inspection I was thinking of coating the inside of the manifold in Corrosion X, Can't hurt right? Anyone else hear of or do anything like this to possibly hold off a little more corrosion???

Thank you for any advice. I really appreciate it.