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André
07-31-2013, 02:57 PM
Been chasing that one for a while.When stopping at the end of the course or to change skier when i start back the engine,sometimes(once every 3-4 stops) idle is high most time around 720 rpm and once in a while as high as 1100 rpm.Reving the engine in neutral won t do nothing and the throttle linkage is fine too when this happen.Only stopping,waiting a few seconds and starting again will correct problem.Just put back my old IAC as this was happening more with the new one.Boat run like a champ other then that.
No codes store.
Checked ECT resistance cold and with 140 hot water.Right on the specs.
Replaced IAC,problem persist...

Anything else related to a intermittent high idle i can check:confused:
T.I.A.
Andre

_fng_
07-31-2013, 03:05 PM
My boat does the same thing and the throttle position sensor and IAC are always suggested in threads like this. I'm not sure if there is a diagnostic test for these without replacing them but that would be nice to know.

Jim N posted previous "Find out if the parts are actually bad before replacing them. The TPS can be checked with a multi-meter.

Remove the throttle cable from the throttle lever- if it stays at normal idle, it's definitely not the IAC and TPS. You need no tools to disconnect the throttle cable." thread I found it on is below

http://www.mastercraft.com/teamtalk/showthread.php?t=37171

André
07-31-2013, 03:16 PM
Forgot to add ,TPS was change last year chasing that one too.
Since there is no codes,i had to try something.TPS,IAC didnt solve it and it s not the linkage,already checked that...

_fng_
07-31-2013, 05:46 PM
Did you buy a regular 350 TBI TPS? I'm thinking about throwing money at my problem as some people say it helps and people have said they got them at local stores but I'm not sure.

André
07-31-2013, 08:27 PM
Did you buy a regular 350 TBI TPS? I'm thinking about throwing money at my problem as some people say it helps and people have said they got them at local stores but I'm not sure.

Yes.Got it from NAPA.Don t have part number,sorry!

JimN
07-31-2013, 08:43 PM
Forgot to add ,TPS was change last year chasing that one too.
Since there is no codes,i had to try something.TPS,IAC didnt solve it and it s not the linkage,already checked that...

Remove the throttle linkage from the throttle body and see if it settles down to the correct idle speed.

André
07-31-2013, 08:46 PM
Already checked and remove linkage and Perfect Pass.Throttle return freely to rest...
Only way to return to a normal idle (and still a bit high at 650-660.Normal for my boat was always 610-620 rpm) is to shut down and restart ...

bret
08-03-2013, 07:51 AM
Is your throttle linkage hitting the transmission cable upon return...this was my case at the end of the course after a run. I had my trans cable tie wrapped by the forward lifting eye and the perfect pass linkage was just barely touching, causing me a 1100 rpm idle. cut the tie wrap and let the cable go, it moved to the right a bit and now all is well.

CruisinGA
08-03-2013, 09:22 AM
Have you checked/cleaned your throttle body?

Sometimes oily deposits can build up and prevent the throttle plate from closing all the way.

André
08-03-2013, 10:38 AM
Thanks guys.Will triple check my linkage and throttle body!
But the reason i don t think it is mechanical is that turning the engine off and starting again will clear the high idle and return to 620 to 660 rpm depending and i can visually check that the linkage is returning to his rest position.Can t move it by hand to close it more.
Thanks !

JimN
08-03-2013, 10:44 AM
Thanks guys.Will triple check my linkage and throttle body!
But the reason i don t think it is mechanical is that turning the engine off and starting again will clear the high idle and return to 620 to 660 rpm depending and i can visually check that the linkage is returning to his rest position.Can t move it by hand to close it more.
Thanks !

Next time it happens, remove the throttle linkage from the throttle body and see if it settles down. If it does, you'll know it's a linkage problem and if not, shut it off and see if it settles down when you re-start. If it does, it points to the IAC.

Also, when you shut it off, do this with the engine cover open and listen for a soft buzzing sound. It should continue for about 5 seconds. This is the IAC "re-parking". It sounds like yours may be doing this, but may not be responding when you return to idle. Unplug the harness and check the contacts. It may only need to have this unplugged and re-inserted to cure the problem.