[luke7575]

Ive had plenty of boats, not saying i think i know whats wrong but, my thought is its unusual for there to be a problem with the engine if its running fine with no sign of miss fires.

Do you have captains call on it.

[theeasynine]

Yes it has captains call. Would one of the flaps staying closed cause that bank to run hot?

Edit: just left marina talking to the tech. The port exhaust manifold runs 160 on the water, starboard hits 220. Which explains why it vapor locks since thats the side the fuel line runs. He was looking through mercruiser service bulletins and found one that pertains for us. It said with 3" manifold risers, captains choice should not be installed...guess what this boat has installed. Yep you guessed it. Anyway I think we are making ground. He also found a loose ground fitting on the battery ground cable, had it taken off and was still getting power on the dash. He pointed out some wires running to the ECM that were melted from the starboard manifold also. This thing is a mess. I hate what previous careless owners do!

[ColoradoDiablo]

All the flap for the capts call does is divert the exhaust , it doesn't close off the flow.
If you had a solenoid not working and one was open to thru hull and one was open to prop , you'd know it.

[theeasynine]

More bad news. Sounds like the hot side had a bad head gasket. Going to have both sides done. Maybe will have this up and running before summer is over.

[luke7575]

cool and good luck its an intensive job when doing it on a boat.

[theeasynine]

Update: got the boat back yesterday and she runs better than it has since I've owned it. Ended up replacing head gaskets, distributor cap was worn, captains choice exhaust was rotted out inside bilge, pieces of former impellers was blocking the oil cooler, replaced sea water pump and fuel pump, and fixed some burnt wires going to the ECM. The tech said inside the rotor cap there was actually mold. Yuck. I couldn't believe how good she ran, we are figuring out the previous owner(s) did not care much for maintenance. Hopefully no more getting towed in. But remember, a bad day on the lake is still better than the best day at work.

On a side note I finally decided on a name. liquid asset