Condition of risers/manifolds in a Mercruiser

FiremistSLK

Active Member
Sep 10, 2020
106
Central Florida USA
Boat Info
2007 Chaparral Sunesta 214 Mercruiser 5.0L MPI Alpha 1
Engines
5.0L MPI 260hp w/Alpha I
Is there any way to determine the condition of the risers and manifolds on an older Mercruiser I/O without removing them? I've heard they should be replaced every 3 to 4 years or so, but how to you know if they have been done? Will a laser thermometer tell anything? The previous owner most likely will not allow them to be removed for inspection.
 
Is there any way to determine the condition of the risers and manifolds on an older Mercruiser I/O without removing them? I've heard they should be replaced every 3 to 4 years or so, but how to you know if they have been done? Will a laser thermometer tell anything? The previous owner most likely will not allow them to be removed for inspection.
Fresh water or salt water? Does the previous owner know when they where last changed? Those are the key questions. If salt and it's been awhile, may as well change them as a preventative measure. Less important if always fresh water. A laser thermometer might tell you if there are hot spots.
 
From what I read on here. When the engine is warmed up, you should be able to hold your hand on it. If it’s too hot to hold, that is an indicator that the manifolds are getting to their end of life. With that said, I would think the infrared thermometer would be able to tell you if there is an issue
 
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It is always better to be safe than sorry.The laser temperature gun looking for hotspots is excellent and probably the best but a really good visual inspection will help as well.Make sure you don't see any water/rust leaks at any of your joints or exhaust manifolds.It is easy enough to see if there is any paint flaking or leaking indicating some heat or over heating. I wish I didn't have any experience on this subject but I unfortunately learned the hard way.
 
Fear, Uncertainty, and Doubt rules the day with the raw water circuit.
3 years tops in Florida Salt Off them to others who will take a bigger risk than you. Diligent use of Salt Away properly, and running the engines as Merc envisioned will probably increase that time, but who knows. The issue is like a pressure plumbing leak in your house, you'll never know just how close you are until you are on the other side of the breach. Then, you will know 100% you are in trouble.
 
Is there any way to determine the condition of the risers and manifolds on an older Mercruiser I/O without removing them? I've heard they should be replaced every 3 to 4 years or so, but how to you know if they have been done? Will a laser thermometer tell anything? The previous owner most likely will not allow them to be removed for inspection.

Probably depends on where you boat. Here on Long Island you can usually get 5 years out of the Mercruiser brand in our saltwater, less with the aftermarket brands.
Frequently checking the heat level on the risers is always a good idea though. Especially once the exhaust is three or more years old.
 
Probably makes sense to replace based on a set schedule determined by your use, maintenance, and if fresh or salt.

This way there’s no guessing. Just a operating cost every 3-4 years.
 
First of all... I LOVE your boat! She's a beauty! I am currently in the market for a clean SR 215ec for next season! As for the manifolds and risers you are looking at, they seem to be for a "Go Fast" boat. I would think that a set of ceramic lined risers from Mercruiser would provide the extra length of service you are looking for at perhaps a slightly lower price? Just my 2 cts.
 
Thank you. I'm not too concerned about the price and there really isn't too much of a difference from OEM and these when you add 6" risers IMO. I'm always updating and keeping up on things with her. She's my hotrod or Harley. However, I don't do anything that will make her gaudy. These look like they would perform better and add a bit of bling to the engine.
 
Ahh.... Now I see where you are coming from.... and I agree with you that they look pretty good and should give you a bit more power. You sound like a person that will not be satisfied with something that is not exactly what you want. If you do not get these risers and manifolds, I imagine you will not be happy with the stock OEM replacements. Get what you want!
 
Ahh.... Now I see where you are coming from.... and I agree with you that they look pretty good and should give you a bit more power. You sound like a person that will not be satisfied with something that is not exactly what you want. If you do not get these risers and manifolds, I imagine you will not be happy with the stock OEM replacements. Get what you want!
I've been eyeing up manifolds for the last year as well. Anyone see an issue with these. (freshwater) I'd need the the taller set.

https://www.hardin-marine.com/p-906...avo-small-block-chevrolet-exhaust-system.aspx
please let me know if you purchase. would like a pair for my 290 .

ralph
 

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