I have a 572 Quadrotor EFI that I messed up. Boat ran fantastic but had developed a problem with the engine loading up if it idles too long. So This weekend I took it out ran to the usual beach and boat ran beautifully. While waiting for my friends to pick their spot on beach I decided to unplug the ECT sensor thinking it may be telling the system that the engine is cold since I do not run a thermostat. So I shut the engine off and unplugged the ECT sensor, restarted the engine and the amount of black smoke was amazing! I shut the engine off plugged the sensor back up restarted the engine with no difference....black smoke everywhere. I limped in to the beach and shut it off. I turned off my battery switch and proceeded to shoot the sh** for the next couple of hours. I got back in the boat turned on the battery switch restarted it and it cleared out. I took the boat out and made a 100 mph pass with no problem. Went back to the beach and bull shi**** for a couple more hours. Time to go so started boat right up backed out took off no problem. I noticed my friends were taking longer to pack up than me so I shut the boat off and floated for 5 min . Restarted the boat again and It looked like I was burning coal! Bottom line I got towed in. I don't have a clue. What could unplugging that sensor have done?

who's computer is running the efi?are all the injectors at the back of the whipples?who tuned it?
I've tuned a few quad rotors and none of them blow black smoke and can idle for hours.
you probably need an in boat tune section.

This is the 6th season I have had the boat. It used to idle forever with no loading at all. After sitting one winter it developed the problem. I removed the injectors and had them cleaned and tested (10 of them) with no improvement. This is only a problem if the boat idles awhile. Otherwise it performs great at 35 mph or 100mph. My tinkering this weekend has caused a REAL problem.. I bought the boat as is so I don't know a lot of details about it. The injectors are in the back. I live in Southern Indiana and don't know of anyone around here that knows about a engine like this. Before I unplugged the ECT sensor Saturday the boat was great. Unplugging it did something . My experience while at a Ford dealership for 27 years was that unplugging a sensor and plugging it back in would leave no negative effects. I shut the engine off first so as not to possibly spike something and was shocked that plugging it back in didn't return things back to normal.. As it is now it fouls plugs and puts out black smoke.

My guy has plenty of experience with whipples. MefI as well as holley efi . Kevin hadley. HADLEY PERFORMANCE MARINE. 513 532 6620 tell him chad sent you

Ben Precision Power Offshore

Mark Precision Marine

Eddie Young

Retter Engine Development

Etc.

Sounds like a Whipple Supercharger

Some of them have an idle bypass in the blower, wonder if yours is working properly?

When you unplug the ECT your computer things it is -40C. So it is dumping fuel into it, large amounts of fuel. I would wager that you fuel fouled the plugs. Put a new set in of spark plugs, that will probably do the trick based on your description.

BTW Kevin, thanks for the plug. ;-)

Take a look and see if the diagram at the fuel pressure regulator went bad I have seen this happen a few times. And tons of black smoke. Just disconnect the vacuum line and turn the fuel pump on and see if it leaks.

I am actually going crazy over this. replaced plugs,Map sensor,ect sensor,intake air sensor, distributor,tps sensor, fuel pump runs,12 volts to three prong plug for injectors not ground signal to injectors. Squirt carb cleaner into superchargers and engine starts (for a couple seconds). so.....I am not getting the fire signal to injectors which works off of a ground. traced wires from all sensors to J1 and J2 plugs on Mefi3 and all test good. All this started from unplugging the ECT sensor? REALLY! Talked to Dustin, and Eddie at Young for ideas. Both said unplugging the sensor should have done nothing to damage anything. By the way...the tach registers 2 or 300 rpm while cranking. Oh....tried a friends Mefi3 just to see if it would start......nope. This has been a terrible boating season around here, the worst I have ever seen because of rain and high water conditions and now this. I have had the boat out 2 times! Good news is there are several bridges nearby if I need to throw myself off one ! Just kidding of course but wow am I lost!

Lesson 1: if its not broke, don't mess with it.


In all seriousness I hope u figure out what's wrong. Lack of boating makes people crazy. Just look at what happens around here during winter

So true endeavor1. Didn't get in the water till late July because of high water and crazy rain. Now this! Should have taken the money for the season ramp pass and bought some antacid instead!