checking risers and manifolds for hot spots

R

Ralph vaughn

Member
Nov 14, 2018
259
Atlanta Ga
Boat Info
2007 Sea Ray 290 radar & GPS, triple axle trailer. 2006 Sea Ray 280 radar & GPS & triple axle tlr
Engines
5.0 MPI closed cooling Sea Core engines & Bravo III outdrives
4.3 MPI with alpha outdrives
my 5.0 engines that are fresh water cooled have 265 hours. i would like to check my risers and manifold for hot spots using a infrared thermometer but i’m bat sure which infrared thermometer to buy as i don’t know the expected heating range. they have thermometers from -55 to +1350 degrees

also not exactly sure where to check on the manifolds and risers.

thanks for you help in advance

ralph
 
I get my IR guns on sale when they drop to 19.99. First thing I do with a new one is aim it at boiling water. If close to 212F or 100C good to go. I draw up a picture of manifold and number many spots on the areas I can see. Shoot them a few times a season and if they read the same or close figure all is well. With 2 engines I look to see if they are close to the same. Never found any difference between engines.
 
northern said:
I get my IR guns on sale when they drop to 19.99. First thing I do with a new one is aim it at boiling water. If close to 212F or 100C good to go. I draw up a picture of manifold and number many spots on the areas I can see. Shoot them a few times a season and if they read the same or close figure all is well. With 2 engines I look to see if they are close to the same. Never found any difference between engines.
Click to expand...
Thanks Northern. Great information about checking the different spots.

ralph
 
northern said:
I get my IR guns on sale when they drop to 19.99. First thing I do with a new one is aim it at boiling water. If close to 212F or 100C good to go. I draw up a picture of manifold and number many spots on the areas I can see. Shoot them a few times a season and if they read the same or close figure all is well. With 2 engines I look to see if they are close to the same. Never found any difference between engines.
Click to expand...
 
The manifold will be the hottest at the exhaust port from the cylinder head to the manifold. That's near where the explosion took place. The coolest should be at the exit of the manifold elbow, top rear if all is going well. My experience is when the top of the elbow starts getting hotter, then it's raw water pump impeller time, or look for blockage in the raw water circuit time.
exhaust manifold.PNG
 
Thanks everyone

Great information from SeRay boaters and I really appreciate the expertise available on the Sea Ray Forum.

Ralph
 
Ralph vaughn said:
Thanks everyone

Great information from SeRay boaters and I really appreciate the expertise available on the Sea Ray Forum.

Ralph
Click to expand...

Here's one for ya. Even the best one is more accurate, the closer to and perpendicular to, the surface you are measuring. Real close is not as important as perpendicular. Also remember, you are only measuring the surface.
 
Here was my thought...periodically I could check the temps of the risers and manifolds to see if there's a trend upward in temperature indicating a possible blockage from corrosion.
Some say the risers/manifolds should be replaced in the five year range. Good PMS but expensive.
I would assume that flushing the engine after each use would increase the time before replacement. Thoughts??
 
Thanks for the responce. With engine cooling water temperatures running in the one sixty to one seventy range..I'm not sure I would touch them..
Looking more closely at the manifold cut out has given me a couple of points to dob with white paint. I have a meter to test the temperature.
Thanks for your response.
Cheers
 
IR gun is helpful to have around but, not for guessing if exhaust is any good.
If saltwater touches it, replace every 5 years with new OEM.
No discussion, no hour limit, no brackish water non-sense....toss it at 5 years!
Install new OEM parts and you’re good to go for another 5.
Pleasure boating isn’t inexpensive..
 
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