Riser Temp Question

[Boater31]

Hello All,

I just started my boat for the first time this year. Its a '99 4.3L with Alpha 1 Gen 2 (0L323711). Good news is it fired right up without much fuss. Ran smooth and everything else checked out. My only concern is after about 15-20 minutes running all under 1500rpm, the port riser became hot, couldn't keep hand on for more then couple seconds as well as the rubber boot started feeling real soft. I shut down and let the hose run a few more minutes. The line leading to the riser was cold, the starboard riser stayed normal maybe little cooler. I opened the drain on the port riser after shut down and with hose running and water flowed from it. The boat was on a angle during (starboard was low side) this as indicated by the pictures. Does this have as large effect as I think on how the manifolds cool. I'm going to try and run it again tomorrow and try to be more level as well as buy a laser thermometer. There were no problems before it got winterized.

I also could not get temps above 130-135ish. I know this could be because hose water was still pretty cold and as I said rpms stayed below 1500 but not sure if it should have gotten higher. I got the boat end of last season and ran it once to test it all, temp never got above 140ish but that was in 40-50? water so I assumed that's why.

Thanks in advance

 

[achris]

Exhaust elbow temperature variation is common. Any variasion in water flow between each side will cause that. The only real 'test' is out on the water, running under load. One thing you could do is clamp off (not completely) the starboard hose to the manifold and make sure the port elbow cools down. If it does, all good.

Temperature not rising 'enough' is also due to the engine jiust idling. It doesn't produce much heat like that. Again, out on the water you should find it will run to 'normal'....

Chris.......

 

[Oshkosh1]

Angle (on both axis) will have an affect on the cooling when running on a hose. Water will follow the path of least resistance and if it's canted or tilted the water will favor the "down" side. Also, although they do work fairly well, the submerged drive will pull more water GPM than sitting idling on a hose due to not having a more uniform flow.

Get it in the water, then take your temps again...I bet then even out a bit. Probably wont' be identical but much closer.

 

[Boater31]

Thanks for the responses. I was gonna put it more level and try what you guys mentioned, but when I pulled the dipstick for the oil before starting it was little over 1" above full. Yesterday before the first start it was about 3/4 between add/full marks(oil changed during winterizing). Only thing I can think is water got in oil, it was winterized by a local shop and before winterization he ran compression test with 225 basically across all cylinders. There was no evidence of water in the oil yesterday when it was running even after I shut it down and double checked. The level also stayed the same during the run.

What do you guys think, assuming your going to say cracked block but how can I start testing for this. The interior is out getting redone so I have full access to the engine.

Thanks Again.

 

[Boater31]

Bump now that form is up again

 

[blando]

u said u let the water run with boat off for a while, water may have backed up into exhaust and ultimately into motor and oil pan. drain oil immediately and see if water is in there .