98 SNOB w/ gt40 does not idle after running (1000rpm)

[costplus]

Just bought this boat w/ 320 hours and it starts and runs great. When you start the engine it revs to 1100 and then drops to 6-700 rpm. all is well until you run around the lake and then slow down to idle. at this time it sticks @ 1000rpm and does not drop like it should. I have even reved to 3000 thinking that it was stuck.... no such luck! If you turn off and re-start it functions properly! NEED HELP as this in annoying and it is to hard to put in the boat house when it idles at 1k

[jjgag60]

idle

well after replacing all the sensors on my 02, the best advice is to download the manual for the Gt-40. I took my throttle body off with the butterfly in and cleaned it well. Dont touch the red idle screw. If you unscrew it, the butterfly will stick to the sides of the throttle body and wear. The computer adjusts the idle on our motors. I think the TPS sensor was the best investment to change. It sets the idle from the computer. The other bit of advice is it takes a good six hours for the computer to learn after it has sat all winter without power to it.

[louismblais]

RE: idle

Had the exact same problem with my 02 SANTE. We added a spring to help return the cable to the idle position at the top of the engine and it works absolutely perfectly now. The spring doesn't need to be very strong and there's a place to attach it easily. It's hard to explain just like that though!

[jjgag60]

idle spring

Can you post a picture of where and how you attached a spring

[costplus]

RE: idle spring

I see you added a spring and understand how that might help but was it idling fast all the time or just after running around the lake. Mine idles fine at initial startup and every start thereafter if I simply turn the boat off and re-fire. Just want to be certain

[2gofaster]

RE: idle spring

Because it idles fine when you shut it off and refire, I'd say the Idle Air Control solenoid is sticking. The IAC is the little thing bolted to the side of the throttle body with 2 6mm bolts. It bypasses air around the throttle body blades at the command of the ECU in varying amounts to maintain idle. When you shutthe engine off, it parks itself at a set position. My guess is you change that and all will be fine.

[costplus]

RE: idle spring

That sounds like a winner. I will try this weekend and report back!

[DanielC]

RE: idle spring

Download the GT-40 service manual, from this site.
It has a good troubleshooting section.

[costplus]

RE: idle spring

I installed a spring to pull the throttle cable back and it seems to have helped. I am not sure if this the best fix but it seems to work and for now that is all it gets. thanks for the advice