Motor Hesitation GT-40

[newfoundskier]

I have a 97 Ski Nautique with the GT-40 and have two questions regarding the engine. In gear the motor idles around 700 rpms. I've read it should be closer to 650. Is there a way to adjust the idle? Secondly, after the boat is in gear and I accelerate there is some dead region in the cable where moving the throttle dosn't seems to get any response. Then at a point it seems to hesitate for a split second and then will take off. Almost seems like the boat is starving for fuel. The boat has perfect pass. Thanks for reading.

[M3Fan]

RE: Motor Hesitation GT-40

The computer adjusts the idle via a throttle plate bypass valve which is regulated with a servo. Your high idle could be the computer compensating for other factors which are not correct. I'd start with the easy stuff- FCC fuel filter replacement, plugs, etc. and go from there. You could eyeball the end of the throttle cable and watch it move while someone else pushes the throttle lever forward (boat off). That would tell you if the cable is indeed moving during that "dead area".

[surroundsound64]

RE: Motor Hesitation GT-40

If it's carbureted, on the side of the carb there will be a little screw with a spring around it. Unscrew it. There should be a throttle adjustment somewhere around the same area, adjust it as well.

[Edwin]

RE: Motor Hesitation GT-40

Does it hesitate regardless of whether PP is on or off? Not uncommon at all for the boat to slightly hesitate when powering up with PP engagd.

[jonfo]

RE: Motor Hesitation GT-40

I had this problem on a 1995 super sport and it was the fuel filter. i replaced the plugs at the same time and the problem went away. also make sure you clean out the spark arestor/air filter, it gets clogged with debris.

[mfloski]

RE: Motor Hesitation GT-40

spark arestor/air filter, it gets clogged with debris? Where is this located? What does it look like?

[SGY]

RE: Motor Hesitation GT-40

A motor can hesitate with too much fuel too. Spark arestor is located on the throttle body/air intake which is under the GT-40 plastic cover. It points towards the port side if I'm not mistaken. (its been awhile.) The arrestor is metal with a mesh cage. It slips over the throttle body with a hose clamp.

My boat seems to have slightly quicker acceleration with the PP off. I have the GM Excalibur. Also check to make sure the PP cable is tight. You'll note a tensioning knob usually on the front starboard of your motor. With the engine on, turn it clockwise to make sure it's tight.

[skisix@38]

Re: Motor Hesitation GT-40

The high idle could be because the throttle cable is not going all the way back to it's zero point. That may be a PP related thing or a throttle cable adjustment. Open up the motor cover and while it's in nuetral and running see if you can push back on the throttle linkage and get it to reduce the rpms. second thing is that some years of GT-40 had a "flare" issue written into the throttle calibration so you might check to see if you have the "flare" feature or if your boat was spared.
On the power up where it hesitates; does it do it when you push the throttle lever and then go or does it start to advance the rpms and then stick at 2 - 2.5K rpms? If it's sticking at those rpms until you advance the throttle past that point and then takes off- that's normal PP operation. If it's hesitating right when you advance the throttle, tha tmay be an indication of a fuel pump problem.

I have a 97 Ski Nautique with the GT-40 and have two questions regarding the engine. In gear the motor idles around 700 rpms. I've read it should be closer to 650. Is there a way to adjust the idle? Secondly, after the boat is in gear and I accelerate there is some dead region in the cable where moving the throttle dosn't seems to get any response. Then at a point it seems to hesitate for a split second and then will take off. Almost seems like the boat is starving for fuel. The boat has perfect pass. Thanks for reading.

[newfoundskier]

Thank you for all of the suggestions. I think the hesitation was perfect pass related. I have read about certain year gt-40 's (97's) having the idle flare. I have asked the dealer about this and they seem very hesitant to change the computer programming. Does anyone know what needs to be done?

Lastly, I have noticed if the boat sits a few days and is started. The idle will bounce from 600 to 900 or so. If I give it a few revs it seems to be fine. Maybe this is related to the high idle?

[SGY]

If your dealer is not in the know on the flare issue, contact PCM. Skisix is right and I"m not sure if there was a fix or not.