Engine revving to 2000 rpm at idle speed

[Stevenspac705]

2005 Seadoo Utopia 205 se with a 250 hp Optimax DFI engine

After slightly engaging the throttle in either direction, the RPMs will intermittently increase to 1500-2000, (normal idle is 1000rpm) for 2-3 seconds, sometimes for as long as 5-10 seconds and will continue even when I put the throttle back to neutral. I can sometimes stop it if I rev up to 2000+ rpms but this is a problem when I am near the dock or other boats. I was told that this was a normal occurrence because the computer sensed that the engine required more fuel(???) If it were only a rare occasion that lasts for 2-3 seconds I can live with but when it is longer I had almost put it into the dock once!

1. Is this a normal occurance for these motors or for jet boats?
2. If so, how can I minimize it from happening?
3. If not, any ideas how to fix this problem?


As always... thanks for any input!!! :cheers:

@drhonda
[MENTION=43374]Coastiejoe[/MENTION] told me you were the Optimax man and this would link my thread to you!

 

[Coastiejoe]

Need a space in his name, [MENTION=16022]Dr Honda[/MENTION]

 

[Stevenspac705]

Thanks! What was the wire that you thought might be the issue to again? I had too many things going on all at once when we talked!

 

[Dr Honda]

Got your pm... but why wasn't this in the Merc section? I would have seen it sooner. (I'll move it)

I'm on a tab right now, so I will respond better, later... but I'm thinking the TPS is failing. Or... the throttle links are sticking.

 

[Stevenspac705]

Thanks, I was wondering if I posted it in the wrong section since I had gotten no replies!

 

[Dr Honda]

OK... Going up to your original questions...


No... it's not normal. BUT.. there is a throttle adder, that's attached to the steering wheel. It's only supposed to come in at almost full turn, to help keep control. Personally... it annoys me, and I disconnected it from my boat.

The question on how to fix your problem isn't an easy one, since I've never really seen this issue. But if it was me... here's the list I would go down

1) Verify that the throttle is closing, at the engine. And make sure its not moving when operating the shifter. (This will require a helper)

2) Verify that TPS is ok.

3) Verify that the steering/throttle cable isn't hanging.

 

[Stevenspac705]

Throttle

OK... Going up to your original questions...


No... it's not normal. BUT.. there is a throttle adder, that's attached to the steering wheel. It's only supposed to come in at almost full turn, to help keep control. Personally... it annoys me, and I disconnected it from my boat.

The question on how to fix your problem isn't an easy one, since I've never really seen this issue. But if it was me... here's the list I would go down

1) Verify that the throttle is closing, at the engine. And make sure its not moving when operating the shifter. (This will require a helper)
2) Verify that TPS is ok.
3) Verify that the steering/throttle cable isn't hanging.

So, I started looking through my manuals to educate myself on your ideas and came across a "feature" in the boat called a Low-Speed Steering Control System, this is probably the annoying throttle adder you were talking about. From the book, "Whenever the engine RPM is at IDLE and the steering wheel is approaching the end of its rotation, the engine speed will be slightly accelerated to increase jet pump thrust. This helps steering control for low speed navigation or when approaching/leaving a dock." I believe this is what is going on with my boat. It annoys me too and I would prefer to have full control of the throttle myself. How do I disconnect this thing?

Hopefully this is the issue but for my education can you please answer some rookie questions for me?

What is the TPS?
Verify that the steering/throttle cable isn't hanging where?

Thanks- Brian

 

[Dr Honda]

The throttle that is hooked to the steering is a physical cable. If you look in the helm... you will see a thin cable hooked to the steering box. That's it. You can disconnect it there... but personally... I took it off at the engine. If you look on the port side of the engine, toward the bottom... you will see both cables. The actual throttle cable is heavy, and then you will see that thin cable. As I recall... it's held onto a bracket with 2 nuts. If there's enough adjustment in the nuts... you could just slack that cable, and leave it physically mounted. But... the end is just held on with a plastic snap on barrel. If you take the cable off the bracket... you can pull the cable sideways... and it should pop the retainer apart.


The TPS is the "Throttle Position Sensor." It feeds the computer throttle data. When they go bad... all kinds of strange things happen. Just an FYI... if you do need one... I have one on the shelf, and I will sell it to you for half price. I bought it to see if it could be adapted to the older engines, since it was significantly less $$$ than the older version. ($180 vs $500 !!!)



I would check at the engine. Make sure the ACTUAL throttle links aren't stuck for some reason. (Corrosion, dirt, hard grease, etc)

 

[Stevenspac705]

Thanks Dr Honda, I am grateful for your input and I will give you an update after I check those out.