Thermostat Question?
 

Ok...this question may be trivial but I'm having a hard time figuring out why my motor is running poorly after idling for an extended period of time (long no wake zones for approx. 1/2 hour or more).

When I first put the boat in the water and get it up to temp, I take off and the boat runs flawlessly. After driving it for a while and idling for a while...idle is fine, but when I try to take off the boat just doesn't want to run and it bogs at higher RPMS.

The temp guage usually read around 160 and the "old motor" never had any problems. The new motor is now running at about 195 (according to the temp guage) and the shop told me that my guage was reading about 20 degrees high. Is it possible I have a bad thermostat or one that is too high? The ECM has been reprogrammed along with some head work and a custom cam. What is the stock thermostat?

It seems as if that is the problem as I did open the engine hatch for the last 5 minutes or so going through the no wake and it helped tremendously and ran perfect once I took off.

I think I'm either getting a vapor lock from the heat, or just too much heat period and the boat doesn't want to run. It just bogs at anything more than 3000 rpm after idling for a while.

HELP?

Before anyone can offer you a real answer, you may want to post what motor and model year you are referring to. But, 195* is a little too hot. You are most likely right in your thinking that you are experiencing the beginnings of vapor lock.

The motor is a Gen VI 502 EFI (with VST and no cool fuel).