risers

How can you tell if you need to replace exhuast risers? I do not have any problems, but have read that if they fail they take the engine with them. I have a 1994 305 alpha 1 drive. Also how big of a job is it to replace them?

Re: risers

Does your engine have closed cooling or raw water cooling?

If it's raw water cooled and still has the original manifolds and risers I would recommend changing both manifolds and risers. Otherwise removal for visual inspection is the only way. Below is a pic of a manifold but the riser would be subject to the same standards.

Re: risers

they last 3 to 5 years in the salt on average.. with average flushing. they last considerably longer in fresh water. They either rot out or rust shut.

Re: risers

Thanks. I will wait till the end of this season and pull for inspection or replacement. Also have read that oem replacement better than aftermarket. I have a raw water cooling system. This is the first inboard outboard Boat I have owned.

Re: risers

after a 15 minute run around the bay... how hot are the risers?

Re: risers

If those risers are original from 1994 in a boat that goes in salt water, you are on borrowed time already and I would change them and the manifolds at the beginning of this season.

Re: risers

Boat has been run fresh water only. Stored in a rack in a building after use its whole life. A bit bigger than I wanted but the shape its in and price could not be passed up. It has been maintained well. No rust around the out side of the risers. The out drive is very clean and runs smooth. No leaking in or out with fluids. Impeller for lower unit replaced 2 years ago. Temp gauge stays around the 130 to 140 mark. The risers or not hot to the touch. Hope to get good use this season and than really go through it well over the winter. Also would like to figure out a way to mount a kicker on the back. 94 monterey with a swim platform. Have a 2003 merc 25 hp 2 stroke with less than 10 hours on it with a pt35 hydro tilt plate gathering dust in my garage. I would pull the risers for inspection but I worry about broken bolts and finding the right gaskets to them. I am new to the i/o game. Thanks

Re: risers

More than likely, you are fine then.

Re: risers

I just did a R and R on my manifolds and risers, 1989 merc 5.7L always run in fresh water. They were in great shape. A little pitting and rust on the ouside but the inside looked great. Cleaned them up, repainted and reinstalled. I worried about bolts coming out, etc. but everything came apart fine. Maybe a hour job at the most. $15 in new gaskets. Well worth the effort, but you are probably fine.

Re: risers

I went and sprayed pb blaster on the bolts and I will try to remove them in a few days. Where can I get the gaskets from and what info do I need to have about the motor?