Hey guys,
We installed the whiple intercoolers on our 575 Top Gun and the boat ran flawless for along time. But all of a sudden it started to get real rich and foul plugs. Called Mercury with out telling them about the Whipple set up, and they told us about another IAC valve that you could install to help in idle. Beings we didnt have an idle issue, we elected not to go that route. We just opened the throttle blades alittle bit further and the problem went away! Dont ask, but it did. Before in order to start it you would have to advance the throttle to get it to start. Now it starts up just fine.

Pwrbt33

Powerboat 33, is that boat the Top Gun Spinetickler? and if it is, how many hours on it now?

If fuel pressure is set per PFM's instructions, and you run a smaller pulley than stock, the motor is incredibly rich. It's nothing to do with the intercooler water, it's 15lbs. more fuel pressure than stock, a cooler discharge temp, different blower speed and different manifold pressures which all change the efficiency of the engine, the wrong direction on a speed density system. It will run far better. The new dual IAC system helps the motor idle better, no question and I would highly recommend that update, but I would also lower pressure to a closer. Just know this, the stock ECU is not programmed for higher manifold pressures because the motor was made to run at 4lbs. of boost. But because the discharge temp is lower, more fuel is added, then you add 15lbs. of fuel pressure? Way too much fuel.

Thanks,
Dustin

Yup, thats the boat. It now has over 250 hours on it. When we did the intercoolers we did a valve job and added better head bolts and did a valve job. But other than that and a few drives, he's boated every weekend.

Pwrbt33