Question on riser temperature

[phughes200]

I am trying to buy a 2000 Sea Ray 210BR. It has a 5.0l, 240hp, EFI engine. After the test drive, I noticed that one riser/manifold was noticablly hotter that the other. One riser I could rest my hand on and it felt warm. The other was hot enough to have to remove my hand after 15-45 seconds? Is this normal? I have heard that this could indicate that the water jacket passages are starting to clog. The engine has 250 hours on it and was running about 175 degress on the gauge. This is a fresh water boat that was dry stored.

 

[SeaRide]

Phughes,

Is it the starboard riser? If so, this question has been asked previously regarding small block EFI V8s of this vintage. However, no one has ever posted their results whether their "issue" had been resolved or if there was excessive corrsion in the cooling passages. Also, if you have a chance, take a look at the starboard riser and you will notice a duct running from the riser/elbow to the intake manifold. I do not know what purpose it serves other than possibly ducting warm air to the intake manifold and this may help explain why the starboard riser runs warmer.

If you like the boat and it performed well, I would ask a certified MerCruiser the question and have him remove both risers looking for corrosion and a possible blockage as part of your survey.

Good luck and let us know your findings.

 

[phughes200]

Thanks.

Yes it is the starboard riser. I have asked the owner's mechanic (I live 2 hours away and don't know a mechanic in that area) to look at it. Because of the conflict of interest, I was hoping to gain some insight here,

 

[northern]

The cast iron risers on our boat are cool. The hoes go as high as 140F in one spot. On our jet boat with a 350 the risers are water temperature and hoes just as cool.
It is not much work to get the risers removed. Take them to a rad shop and they can clean them, New ones are not that expensive. About the price of a tank of gas for the boat.

 

[MaddyDean]

Going through this issue as I write. I have been over heating and as it turn out, it has been because of the eel-grass in the bay,

But for troubleshooting i bought a Ryobi IR Thermometer gun and Ray-teched the risers. Noticed the Starboard riser was around 200 and the port riser 160.

I asked my mechanic and he said, " it is because of the rotation of the circulation pump on the front of the engines--water is hotter by the time it makes it to the starboard riser.

he recommended Ray-teching the Thermostat housing and Intake Manifolds. Those temps should be around 160 - 175 mark.

 

[phughes200]

Just some more info. The engine has 250 hours on it. It has been used on a fresh water lake in SC. The boat was trailered. Everything appears to be orginal expect the battery and bildge pump.