74 MPI Starboard Riser Hotter than Port

"My 2001 7.4 has a hotter run

"My 2001 7.4 has a hotter running starboard riser/manifold than the port side. It has a new sea water impeller and is raw water cooled in fresh water. The hose leading from the thermostat housing to the manifold gets pretty warm as well. The port side stays plenty cool. My question is, is this normal, and would installing the water heater kit in the wrong side of the thermostat housing have anything too do with it? It specified the starboard side , it was put in the port side, did it upset the flow somehow? The engine does not get more than 175. Any help or suggestions would be greatly appreciated."

If the instructions said to in

If the instructions said to install the heater on the starboard side why would you install it on the port side?
The company didn't just pick a side for no reason.
If it made no difference of what side this heater was used on there would not have been a specified side to install it on.
You may not be getting enough water into the exhaust manifold now.
These cooling systems do need to have a certain direction of flow.
Just me but I'd install the heater the way the instructions say to.

"It was installed that way bef

"It was installed that way before I owned it, but the instructions came with the boats paperwork and was reading through it and found it. It was probably done that way as the heater was on that side. I will change it myself this weekend and see if it helps."

"Well, I changed the location

"Well, I changed the location of the water heater connection as per mercruiser and back flushed the intake water lines and coolers, got out some debris, but nothing that would stop the flow. I pumped water through the riser hoses and they flow the same. So there must not be and obstruction in them. The port riser is still cool to the touch, and the starboard is somewhat better than before but still warmer than the port. The starboard hose from the thermostat housing still get plenty warm. Tomorrow I will be checking them with a lazer thermometer and get some numbers. My original question is are they suppose to different temps or the same.

Scott"

Good idea on the lazer. Try wi

Good idea on the lazer. Try without the heater. One side could be a little warmer but not much. Check flappers in the Y pipe. Use lazer to follow the heat down the Y pipe.}

Subject: Merc 7.4 Overheating

Subject: Merc 7.4 Overheating

I have the port engine showing 190 at idle and 180 at 1500RPM's. This is the port engine the starboard engine runs around 165. The system is closed coolingThe following has been done:
- Replaced thermosat with 143
- Rebuilt raw water pump.
- Raw water exhaust elbows are new.
- Have changed gauges and same happens.
- Water temp. sending unit has been replaced
- It seems to be pumping the same amount of water as other motor. The motors have 400 hrs on them.
Once in awhile the starter will not engage and I get a clicking noise from the engine circuit breaker reset. Any thoughts?

"Has anyone come up with a def

"Has anyone come up with a definitive answer on the different temps for the port and starboard manifolds. I have the same problem and I do not have the water heater kit installed. I have a new seawater pickup pump, new engine pump and new thermostat."