GT 40 EFI engine problems

boomerzuma · Criminal Joined: 04 Feb 2003 Posts: 95 City: Wichita

My GT 40 EFI (air nautique) has been running poorly since I got it out for the season. It has no power out of the hole, yet top end is fine. I've replaced the fuel filter, drained the tank of gas that sat for the winter & refilled with fresh fuel & yes I put stabilizer in the fuel last fall before layup. I've chnged the plugs, and even cleaned the spark arrestor and it still runs poorly. At lower RPM's it almost seems like it's dropped a cylinder, idles a little rough & sputters on acceleration. I'm about at my wits end, what have I missed?

vette74 · Posted: Jun 01, 2004 1:13 pm Post subject:

Your carb needs a rebuild the accelerator pump is not working properly.

boomerzuma · Criminal Joined: 04 Feb 2003 Posts: 95 City: Wichita

Vette, EFI = electronic fuel injection, no carb on this one.

vette74 · Posted: Jun 01, 2004 1:45 pm Post subject:

Sorry, I did not catch the EFI. I think all boats are a speed density EFI closed loop alpha system so really the only thing that can go wrong is the map sensor or the throttle position sensor. I will look in my book when I get home.

Tiffanator · Posted: Jun 01, 2004 2:00 pm Post subject:

Check your fuel pressure. I had a similar problem with mine, it idled rough, didn't want to accelerate and overall ran like crap. It turned out that the small hose inside the fuel control cell had a 1/4" crack in it and it killed the fuel pressure, we replaced the hose and it ran great.