575 SCi TO RICH!
 

i have a customer that has 575's with pfm kits (innercoolers and smaller pulleys) on a 40ft v bottem and they keep fouling plugs
i f you put in a new set it's fine for a while take it out run it up to over 5000 rpm bring it back to idle and the plugs are fouled up again.
any ideas?
thanks
Jason

What Plugs?
 

What heat range plugs are you running? They may be too cold.

Also it sounds like you may have carb problems, such as running rich, or a bad powervalve.

575 SCi

:rolleyes:

If it's a newer 575sci do you have the bigger 6lb pulley vs the 3 lb available? If not PFM has those as well.
There was also a recent recall on the fuel rails check your Merc service bullitens. Did it start when the chillers went on?

I've had to do a new calibration for these, PFM calls for 15lbs. of fuel pressure more and this is far, far too rich. The fuel consumption is unbeliveable, amazing it even runs.

Thanks,
Dustin

I`ve got PFM Superchiller intercoolers on my Top Gun. When I first bought it I was fouling plugs like crazy. I had installed a water pressure valve in the line feeding the intercooler, and with it set correctly, there is no flow through the cooler until 3000-3500 rpm.
With out the valve, the atomized fuel was turning back to a liquid and puddling in the intake manifold at idle. Some cyls. were lean and the back cyls were extermely rich.

Good luck , Kurt.

:D

probally somewhere between timing,octane,and plug heat range,becarefull you dont want to wash out the cylinders or bearings.....you can ruin a good motor in minutes

running one heat range hotter than stock on the spark plugs and not making any difference...... i really haven't got my hands on the boat to check it out .......it's a promo boat and goes to all the poker runs for advertisement for the company so it's always on the go(behind a truck that is)but i feel that it is a atomization problem the plugs are killer black!

Before and after upgrades?Both engines?
Doug

575 to rich.
 

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:D

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

575's.
 

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