Hot Risers

[wv_waterdumby]

84 supra comp w/ pcm 351

When running the boat on "fake a lake" it runs around 150 degrees and the risers are warm but never hot. I was out on the lake last weekend and the boat was running around 155-160 degrees and the riser would get hot. What could cause this? I did have some leaves and sticks in the oil cooler but I removed those and it still made no change. One more thing...After running the boat to temp and turning it off the tempature rises and everthing get hot, including the water pump(raw water). The temp guage will read 180 degrees, after starting the boat, it drops very quickly to 150 degrees or so. Is it normal for the engine temp to climb after being ran? Thanks guys. Enjoy the weekend.

[docdrs]

It sounds pretty normal. After you shut it down the motor is a heat sink no longer being cooled thus temp rise. On a fake lake you are not stressing the engine thus they will never get hot. jmo

[Sunsport87]

I agree with Doc. Once you shut down on the water the heat has no where to go. This is normal. As long as the temp drops when you start up your fine.

[wv_waterdumby]

Thanks guys. How hot is to hot for the risers. It just seems like they're getting too hot. I may just be paranoid.

[jeffreyk573]

I actually checked mine today, and I can't actually tell you what the temp of the riser was but at idle i could very easily keep my hand on the top of it. Although trying it again after the engine had been shut off for about ten minutes, it was pretty hot. I think that your temps are normal

[docdrs]

prob too hot to touch, enough to give you a burn on your arm

[rludtke]

Thanks guys. How hot is to hot for the risers. It just seems like they're getting too hot. I may just be paranoid.

The risers on my boat are warm to touch when all systems are operating correctly. When my Raw Water Pump loses efficiency, the exhuast risers will start running much hotter, even though the temp gauge is still indicating normal. The exhaust risers will reach skin burning temps. When it gets this hot, I start to encounter vapor lock problems with my carburator.

If you suspect that your exhaust risers are running hotter than they should, replace your Raw Water Pump impellor.

Be careful when running your engine connected to the hose. Avoid any high RPMs, as the water source may not be able to keep up with demand. The water lubricates the Raw Water Pump. If you run the Raw Water Pump without adequate water, the impellor will be damaged.

On the hose, I never run my engine faster than required to keep it running, which might be 1000 rpm when cold, and 600 rpm idle when warm.