port side riser overheating

[skydiveD30571]

If it were me, I would find out which one is triggering the alarm by unplugging the wire that connects to one of them and try to set off the alarm. If you can't get the alarm to sound, plug it back in and unplug the other sensor. Once you know which sensor is triggering the alarm, switch the sensors around to the opposite risers and try it again.

 

[jbauman4306]

Do those temps sound hi? Thanks for your help by the way.

 

[skydiveD30571]

According to another post I've seen on another website (take that as you will) the sensors will trigger the ECM to go into rev-limit mode around 195-205 degrees. Did you use the IR gun on the block/thermostat housing as well?

This thread below sounds like a similar problem, and the late great Don S. believed it to be a clogged riser.
http://forums.iboats.com/forum/engi...s-outdrives/254980-exhaust-riser-temp-sensors

 

[jbauman4306]

I will test again tomorrow on the block and thermostat housing. The temp gauge on the boat sits aroun120f.

 

[alldodge]

Do those temps sound hi? Thanks for your help by the way.

Yes, that's a bit to high. So your alarms are going off as they should, seems to me you have a restriction somewhere or you pump is not pump enough

 

[jbauman4306]

So I pulled off the risers and there is some corrosion. I'll post some pictures later. I found out they are Arco risers not volvo penta. I remember reading somewhere that if u don't use oem you could have problems. Any thought?

 

[jbauman4306]

No Title

Pics

 

[BRICH1260]

It doesn't look like there is enough corrosion present to cause your overheating problem. I bet your not getting enough water pushed through them. Check the water output from the thermostat housing.

 

[jbauman4306]

How would u recommend I do that and how much water am I looking for. Should I pull the hoses of that go to the risers at the thermostat housing starts the boat and reviews it up? Not to long obviously.

 

[alldodge]

That would be one way, but again, start with taking the thermostat housing apart, it my be obvious

 

[jbauman4306]

I guess I forgot to mention I installed a new thermostat and thermostat housing and it's still doing it

 

[skydiveD30571]

I had a pretty bad overheat on one riser last year. Sucked up some dirt, it traveled through the thermostat and block fine, but then clogged up the hose from the thermostat to the exhaust manifold. It got hot enough to melt the rubber exhaust bellows on the y-pipe.

One thing you can try is to unhook that hose from the thermostat, remove the drain plug from the rear of the manifold, and pour water into the tube. That will show you if the path from thermostat housing to manifold is clear.

 

[BRICH1260]

Yep. Pull the hose from the thermostat housing to the manifold riser at the riser junction. Start the engine cold, and run for just a few seconds to check water output. If minimal, that is your problem

 

[alldodge]

Your not moving enough water, so the issue is either a restriction in the intake hose or drive pickup, a restriction in the cooling passages, or the impeller.

Your exhaust looks fine, you replaced the impeller and so long as the impeller housing is not damaged, then the only thing left is the drive and suction hose.

 

[Lou C]

If this is an SX drive there are rubber grommets in the lower unit that connect the water transfer tube from the lower to the upper gear housing. They can rot out and deteriorate and you can lose water flow. There is also a plastic nipple in the transom mount that connects to the water transfer hose that goes into the transom mount. If this cracks same thing.
Those manifold and riser temps are high. On my OMC V6 I get about 100 degrees at idle and 135 or so max after coming off plane. Engine temp is 160-175 max.