Speedster 150 idle varies a LOT

[kg4izw]

One day I will run it and it will idle around 1750 and the next day when I run it the idle will be 2450. Is this normal? What could possible be making this happen? The throttle cable is not too tight because I can push it 1/4inch from idle before the engine ever picks up rpm.
Thanks.

 

[devonte007]

How are you judging the rpm change, just by the tach, or can you also here and feel that the engine is faster/slower?

Reason I ask is that sometimes the gauges can start acting up near the end of their lives, mine for instance sometimes acts up and if I tap it I can change the rpm reading by as much as 1000-2000 rpms. Just haven't had time to take it apart and fix it.

If you are sure that the engine really does run faster at idle sometimes then I would look at the idle control valve which is located on the throttle body. It's main function is to control idle speed when the main throttle butterfly is closed. Could be corrosion issues or just that the motor needs to be replaced.

 

[kg4izw]

Thanks for the quick reply.
I am certain that the rpms are truly changing because on the days that it idles high, I must shift to neutral far sooner as I approach my dock. Also on these days,I am the fastest boat through the no wake zone even when my throttle is off completely.
The boat is well cared for and has 58 hours on it.
Where do I find the idle control valve?
And are you talking about actual something physical in the way as it opens and closes?
Is it like the butterfly that opens and closes as I push the gas in my car?

 

[ken0276]

My Seadoo 155 does the same at the fixed throttle, the rpm digital reading would go up and down for about 500 different, it could be the rpm meter issue, but it didn't bother me at all.

 

[pwgsx]

Check your idle valve and also make sure your TPS is set at 0 when the throttle is all the way back at idle.

 

[devonte007]

Yes, the idle control valve is an actual physical auxiliary butterfly on the throttle which is controlled completely by the computer by way of a small motor. The computer is constantly opening and closing this valve (in small increments) to try and keep the engine idle at a preset value (about 1800 rpm) many times a second.

pwgsx brings up a good point about the TPS as well. He recently went through a lot of trouble to track down and engine issue which ultimately led him to a bad TPS. Read his thread as there is some very useful info: http://www.seadooforum.com/showthread.php?72366-1-engine-revs-slower-than-the-other

If you don't already have one, I would download a shop manual for your boat. One of the unfortunate things about these computer controlled engines is that you may ultimately need to go to the dealer or buy your own candoo pro in order to fix this issue, especially if it ends up being a TPS. When servicing the throttle system, it needs to be reset back to zero and the only way to perform this procedure is with the special computer that connects to the engine.

Might be something simple like a gummed up throttle body or idle control valve but no way to tell until you take it apart to inspect it.

 

[kg4izw]

OK this may help narrow it down..
The last several times I flushed the motor on land, when I rev the motor a bit to flush it faster, the motor does not want to idle back down... it wants to stay at 3000 rpm when I pull it back to idle. But it only stays at 3000 when out of the water on the hose hookup. Since there is different pressures involved (under water versus out of water) wouldn't this more likely indicate idle control valve?
I have been going over the manual breakdowns the past few days, and it is quite overwhelming.

 

[pwgsx]

Yes or the tps might be bad.

 

[kg4izw]

Page 423 of the service manual tells me that I must reset the "closed throttle and idle actuator" if I loosen the TPS, idle bypass valve, or throttle body. And it says it must be done using the BUDS software.
Does this mean I am unable to clean, adjust, or replace any of these air intake parts without a $400.00 piece of hardware?

 

[devonte007]

Unfortunately that is correct. If you service the throttle body you will need to get yourself a Candoo, find someone who has one, or visit the dealer.

 

[RON@COMMONWEALTHUSA.NET]

Idle issues

One day I will run it and it will idle around 1750 and the next day when I run it the idle will be 2450. Is this normal? What could possible be making this happen? The throttle cable is not too tight because I can push it 1/4inch from idle before the engine ever picks up rpm.
Thanks.

Be sure it doesn't have an air leak, will cause pulsating idle.

 

[kg4izw]

It does not appear to have vacuum lines like my old truck does.
what could be the source of the leaking air and why would it leak one day and not the next?
I have so much still to learn...

 

[pwgsx]

Check the idle valve, the tps, throttle cable adjustment might be too tight.

 

[kg4izw]

throttle cable adjustment is correct
and it appears that I will be unable to remove and clean the idle valve and tps without the candoo to reset them.

I guess this leaves these vacuum lines others have mentioned. But I have looked through 100 pages of the manual without any mention of vacuum lines.
Can someone point me in the right direction?

 

[devonte007]

There are no vacuum lines on these engines, none that come to mind or could cause this type of problem anyway. Any vacuum leak in these engines would be from failed gaskets and or mating surfaces. Things like throttle body gaskets, and anything attached to the throttle body itself. Seals only usually leak if they were taken apart and not put back together with a new gasket.

That said, it is not a common problem on these seadoo 4-tec engines. Nothing I have heard about anyway.

More likely your issue has to do with either the idle control valve or TPS.

 

[kg4izw]

For a clean motor with 64 hours, are these parts like idle control and TPS more likely to need cleaning or more likely to have failed?
And what would happen if I cleaned these parts, put them back on, and did the ignition reset thing without hooking it up to the candoo?
Or do I really HAVE to have the candoo to make it work properly again?

 

[devonte007]

Parts like the TPS and ICV are electronic devices / servos and are not really made to be taken apart, cleaned and put back together. I'm sure it is possible to do if you have the correct experience but not something that would work out well for the average person. Replacement is the best choice.

Difficult to say when and why parts like this fail, but salt water environments shorten the life of everything on a watercraft - not to mention the generally moist environment...

It is my understanding that if anything on the throttle body is loosened or removed and then replaced, the reset procedure must be performed for proper operation. What would happen if you didn't perform the reset procedure? Hard to say, if you are inclined to do so give it a try. If it runs poorly I think you will know why.

The only thing that can be cleaned are the mechanical throttle body parts themselves, butterfly valves, intake surfaces, etc. After you get it off you may find that some of the mechanical parts are simply corroded and need to be lubed. You can also test the TPS using a multimeter (without removing it), this is outlined in the manual; resistance tests.

In summary, this is your machine and you can do with it what you want and experiment if you wish. The proper way to reset the throttle body after maintenance is outlined in the manual. YES you HAVE to have a candoo or take it to the dealer.

 

[kg4izw]

Thanks so much for all the help. When I ran it the other day, the idle was right where it belongs. And I have made no changes. Since this does not appear to be a safety concern, I think I will just run it like it is until I get an error code. And then at least I will know where to begin.