Riser too hot?

[Stingray1999]

My boat didn't have a thermostat in when I bought it so I fitted new sender and stat, when I started her on muffs the right riser got very hot and the left only around 80 what could this be.
200cx stingrast4.3 by 1999

 

[Bt Doctur]

clogged manifold, clogged elbow

 

[tank1949]

You can buy an inferred thermometer that works great and determine actual temp. Former may have pulled stat. in lieu of believing defective state was causing heat issues. BUT, w/o stat, motor willl not perform optimum. Risers are easy to pull and if boat is salt water motor, they should be inspected yearly. Risers usually become plugged and need to be unplugged and eventually replaced before exhaust manifold goes bad.