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russlars
07-12-2012, 02:19 AM
After a long road trip the throttle cable came unscrewed and I am trying to get my idle speed set correctly so I get a nice smooth shift into gear. Can anyone tell me what the correct RPM should be at idle speed? Any other tips on fine tuning the cable length so it shifts smooth again?

russlars
07-17-2012, 11:18 AM
Still looking for a response. What is the ideal RPM at idle?

jmw
07-17-2012, 11:26 AM
All fuel injected engines idle about the same around 650 rpm but if you're looking for an exact rpm/setting maybe a one of the engine gods will post soon.

mwg
07-17-2012, 11:55 AM
Once warmed up mine ('01 205v w/ the LTR) idles around 700 rpm..

russlars
07-17-2012, 02:12 PM
Thanks. For some reason I was thinking 800 RPM so I will back it off some and see if that helps the shifting issue also.

PT 1999 ProStar
07-17-2012, 06:32 PM
Thanks. For some reason I was thinking 800 RPM so I will back it off some and see if that helps the shifting issue also.

Sorry Russlars for late response. I have same motor and it's at 650-700.

russlars
07-18-2012, 02:18 AM
Sorry Russlars for late response. I have same motor and it's at 650-700.
Thanks. I'll be working with it tomorrow trying to get it purring again.

JimN
07-18-2012, 07:48 AM
Thanks. For some reason I was thinking 800 RPM so I will back it off some and see if that helps the shifting issue also.

Did you make it go up to 800 RPM? If so, you screwed up the factory setting for the throttle plate and that's supposed to be fixed. The throttle plate DOES NOT set the idle speed- the IAC does that, which is why it's called the 'IDLE AIR CONTROLLER'.

This is not a carburetor. You do not have user-adjustable settings for idle speed, fuel mixture, timing or much of anything else. This is not designed to make it hard for a user to work on their own engine, it's so it performs a certain way and meets EPA/CARB emissions, although these aren't quite as stringent as what is mandated for cars and trucks.

Unless you know what you're doing, don't mess with the idle stop. If your idle is too high, you should take the throttle cable off and see if it settles down. If it does, your cable or throttle pawl at the helm may be binding. If it doesn't settle down, have the IAC re-parked before doing anything else. Don't remove the IAC and turn the key ON or OFF- the pintle can come out and if this happens, it will be out of its normal range and at that point, it will definitely need to be re-parked.

Would you try to adjust the idle speed on your car?

russlars
07-18-2012, 10:04 AM
Thanks for the reply Jim. So here is the scenario. After a long road trip I put the boat in the water. It ran fine for the first set. On the second set the boat would go into gear but past that spot the throttle lever would just slide forward but not exceed idle speed. Upon inspection we noticed that the throttle cable was completely disconnected so we put it back together and for the next three days continued to try and adjust the length of the cable with the nut to get it idling correctly. When it is first started in the morning the idle speed fluctuates all over the place and it requires several restarts until it the engine gets warmed up and then it runs pretty decent but doesn't have the bottom end pull or top speed that it used to. We were boating at 6,000 ft so I chalked this up to the elevation even though I know that shouldn't be a factor with a fuel injected engine. I haven't had it back in the water since we returned to sea level and I was just crossing my fingers that if I could get the idle speed set correctly by adjusting the cable that all of the other issues would go away. Sounds like that is wishful thinking! Can you explain what "reparking the IAC", " pintle", "throttle pawl" and all of that other mumbo jumbo means to a novice like myself?
Is this something that about any boat shop could do or does it require a visit to the dealer which is a couple hours away?
Thanks again for your help. I really respect your opinion, I just don't completely understand it and was hoping that something that appeared so simple could be fixed without a trip to the dealer.

JimN
07-18-2012, 11:06 AM
Thanks for the reply Jim. So here is the scenario. After a long road trip I put the boat in the water. It ran fine for the first set. On the second set the boat would go into gear but past that spot the throttle lever would just slide forward but not exceed idle speed. Upon inspection we noticed that the throttle cable was completely disconnected so we put it back together and for the next three days continued to try and adjust the length of the cable with the nut to get it idling correctly. When it is first started in the morning the idle speed fluctuates all over the place and it requires several restarts until it the engine gets warmed up and then it runs pretty decent but doesn't have the bottom end pull or top speed that it used to. We were boating at 6,000 ft so I chalked this up to the elevation even though I know that shouldn't be a factor with a fuel injected engine. I haven't had it back in the water since we returned to sea level and I was just crossing my fingers that if I could get the idle speed set correctly by adjusting the cable that all of the other issues would go away. Sounds like that is wishful thinking! Can you explain what "reparking the IAC", " pintle", "throttle pawl" and all of that other mumbo jumbo means to a novice like myself?
Is this something that about any boat shop could do or does it require a visit to the dealer which is a couple hours away?
Thanks again for your help. I really respect your opinion, I just don't completely understand it and was hoping that something that appeared so simple could be fixed without a trip to the dealer.

These, being injected, compensate for air/fuel needs on the fly. The first thing that happens when you turn the key ON is the MAP sensor lets the ECM know the barometric pressure. That, along with engine temperature, Throttle Position Sensor (TPS) and Manifold Absolute Pressure sensor (MAP) takes care of any fuel requirements. The IAC that I mentioned before determines the actual idle speed and, by following the throttle's major movements (hard acceleration or deceleration) works to keep the engine from bogging or taking too long to come down in RPM when the throttle is slammed down.

If you know someone who's familiar with GM fuel injection, they can advise you.

As I posted, if the RPM at idle is higher than about 700, you may need to look for tightness/mis-adjustment in the throttle cable. If it doesn't drop to 700 RPM with the throttle cable removed from the lever, it needs to be connected for diagnostics. Malibu and Supra/Moomba use Indmar engines, too. If a MC dealer is just too far away, these can help you.

russlars
07-23-2012, 02:16 PM
Thanks so much for your help, Jim. I disconnected the throttle cable before I started her up. She idled at around 650-700 RPM just like she used to. I then reconnected the throttle cable making sure not to add any tension on the cable to alter the idle speed and she runs like a champ and shifts nice and smooth like she used to. Glad it was an easy fix!:D
I'm so glad that you are on this forum to help novices like myself and keep our boats on the water where they should be.