1998 5.7 mercruiser starboard riser hot

[canal cruiser]

Last year starboard side overheated hot enough to melt rubber couplers etc. towed in.Just finished replacing both exhaust manifolds and risers.New flappers etc.Started with the hose muffs and noticed starboard side riser hotter than port. Port side cool to touch but starboard hot and getting hotter. I'll check for water blockages and get infared temp but, what else could be causing this? I'm hoping it's something easy as frustration is setting in fast. Any help is better than a sharp stick in the eye. Thanks.

 

[Fun Times]

Re: 1998 5.7 mercruiser starboard riser hot

Hi there, This may depend on how hot it's actually getting to as it's not all that uncommon to see almost a 20 degree temp differences between the two sides. Typically the starboard side runs a bit warmer.

Have you inspected the thermostat housing and changed out your thermostat and related parts. Sometimes that may help.

Also your sea water pump impeller, housing, and gaskets need to be in good working order or you could notice a temp difference at the exhaust system as well.

Hope you get it all figured out soon, Good luck.

 

[canal cruiser]

Re: 1998 5.7 mercruiser starboard riser hot

Fun Times, Thanks! most of what I've found on line says the same as you, starboard side runs warmer. Impeller and thermostat was changed at shop before the over heat last year. That wasn't the first melt down, happened the year before last as well. Yesterday checked the manifold drains and both had plenty of water in them. I may be overly worried but, after two almost fires and tows to the dock I'm not taking any chances.