90 Mastercraft idling too high? Help?

(bbeach) · (bbeach) **Join Date: Jul 2002** 08-09-2004, 2:47 PM

My boat has the 351 Indmar and recently when I come down off of plane my boat will idle to high and I have to rev it up to get it to come back to a normal idle. Could this be the perfect pass module? Or is it something with the carb? Any suggestions?

(bigjackamo) · (bigjackamo) **Join Date: Aug 2002** 08-09-2004, 3:16 PM

I think you need to replace your boat and get a wakeboard boat instead of a slalom boat!!!!

Just kidding Brad !!!

(fatsac) · (fatsac) **Join Date: Jun 2004** 08-09-2004, 3:24 PM

My dad had the same problem in his old cabin cruiser. Turns out, after massive carb adjustment, the throttle cable was stretched. Replaced the cable and never had a problem.
My 2 cents...

(puckinshat) · (puckinshat) **Join Date: Sep 2003** 08-09-2004, 5:36 PM

Mine was the alternator making the engine idle 200 rpm high. Have you added any electronics recently? Also, I know on my old I/O mercrusier there was just a little screw you would tighten or loosen on the carb to adjust the idle throtle. Im not sure if it the same on yours, but take a look at the throtle cable and try to figure out how it works.

(mikeski) · (mikeski) **Join Date: Aug 2003** 08-09-2004, 5:49 PM

Check the choke cam on the side of the carb.

(bbeach) · (bbeach) **Join Date: Jul 2002** 08-10-2004, 8:52 AM

Thanks guys I'll check these things out. Is it at all possible its the perfect pass module somehow not returning the spool to the original idle position?

And no Phil I don't need a wakeboard boat!

(mikeski) · (mikeski) **Join Date: Aug 2003** 08-10-2004, 12:39 PM

The perfect pass by design should only be capable of reducing speed, never increasing. Can't happen unless something is not installed correctly.

More detail if needed...
When you accelerate with the PP activated it reduces your throttle input, the servo feeds back against you. After it is engauged it will make adjustments up to the maximum throttle opening where your handle is. So if your throttle handle is halfway it cannot ever accelerate more than halfway, if it's at idle it cannot accelerate more than idle.

(bbeach) · (bbeach) **Join Date: Jul 2002** 08-11-2004, 7:33 AM

that makes sense... it sounds like it is my throttle cable for the carb... I'll look at it tonight when I get to the lake...

(bbeach) · (bbeach) **Join Date: Jul 2002** 08-12-2004, 9:41 AM

Turns out it was the return spring on my throttle cable that was worn out... Replaced it and its working perfectly!