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2005 200 Optimax

fishinwrench

fishinwrench

Contributing Member
Sat for 3 years and had to have boost pump replaced and VS overhauled. Now it starts and idles fine but when you shift it into forward gear it trys to rev out of control and has to be shut down. Any ideas?

Thx
 
If you had it at a dealer to do the boost pump and VST, i would be taking it back for him to sort out... It shouldnt of been returned to you like that.
If you want to check it out yourself.. Start by disconnecting the throttle cable at engine side.. Check to make sure linkage is against its stop.. It should be.. Start engine and shift to forward.. If it still idles ok now in forward, you will need to re adjust the throttle cable..
If it still revs, shut it down and remove flywheel cover (big plastic cover on top of engine) Make sure throttle butterfly is completely closed.. also look at the TPS.. It should be intact and with linkage connected between it and the main throttle arm... Let us know what you find...
 
Just to clarify; The VS wasn't serviced by a dealership, I did it myself and Opti's are fairly new to me.... but I'm learning.

No fault beeps. Butterflys remain closed. It will not rev with throttle only but shift it just into forward gear (no throttle) and it immediately revs out of control and has to be shut down quick.
Thought it might be possible that fuel was getting to the air side....but if so how could it start and idle so smoothly ?
What in the world could be causing it to rev so quickly just by dropping it into gear?

It's crazy, and could be down right dangerous off the trailer. Not to mention hard on the gears.

Whatever condition causes this it needs to be addressed and checked on all Opti's.....because this could kill someone. Seriously.
 
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Check the items I mentioned above...
The only link between shifting into gear and throttle control is the control cable adjustment.. As you are moving into forward you may be advancing the throttle at the same time...
Does it rev out of control if you shift to reverse???
Another possibility but highly highly unlikely is a faulty computer reving the engine crazy when it detects an in-gear position from the neutral switch..
 
Haven't tried reverse because I don't want it over reving without a load on it.
I know this is hard to wrap your head around but seriously I could disconnect the throttle cable completely, drop it into gear and if I didn't shut it down immediately it sounds like it would hit 4-5k on the muffs.

Im afraid it would jump the trailer and run through the back of the truck befote I could pull the kill switch or turn the key off if it was in the water on the trailer.

So do you think "computer weirdness" ? Stuck open injectiors? I'm confused mostly because it will start and idle perfectly in neutral. This is crazy, and a bit scary to be honest. I can just visualize some guy with an Opti pulling off the trailer then putting it into forward and mowing down 4 boats at a tournament takeoff. Not cool!
 
I very much doubt it would be an ECM (computer) issue.. but my chain of thought is the only possible link between shift and throttle is the neutral switch.. when you shift, this switch sends a signal to the ECM, when the ECM receives this signal, an internal fault may cause it to think its at 100% throttle... But this is what fairytales are made of... Highly unlikely yet still minutely possible...

Have you tried shifting the engine without it running while looking at the throttle arm that the cable is connected to? Is it against its idle stop?
Be careful when shifting without engine running... You may need to turn prop a little to help it mesh..
 
Yes sir I have, the throttle cable does not move when Just dropped into gear.

And when throttle is advanced in neutral the engine bogs, will not rev in neutral at all...... but shift into forward and it acts like you floored it.
 
Throttle cable and control components are operating perfectly. This is a mind bender. I'm surprised that this has never happened on an Opti before. If it turns out to be a computer glitch Ill be forever leery of any Optimax powered boat pointed in my direction, I know that much.

Wasn't there a DFI Toyota car that was doing something similar awhile back? I remember hearing about it on the news. Didn't the manufacturer try to blame it on floormats or some crap when they couldn't determine the cause?
 
...just into forward gear (no throttle) and it immediately revs out of control and has to be shut down quick.
Click to expand...
Verify that the TPS is working properly w/a digital volt/ohmmeter. You can do an ohms test and see the change as you slowly turn the TPS. You can also do a voltage test w/engine off but ignition on and see it change uniformly. If it makes a wuick jump/change in ohms/volts you found the problem.
 
You got me scratching my head over this one now... And... An opti has yet to beat me...
Your next step would be to disconnect the shift switch wires...short out the 2 that go to the harness... by this you are telling the ECM that the engine is in neutral... Now shift to forward... If it idles at this point... then you have an ECM fault...
 
guyjg said:
Verify that the TPS is working properly w/a digital volt/ohmmeter. You can do an ohms test and see the change as you slowly turn the TPS. You can also do a voltage test w/engine off but ignition on and see it change uniformly. If it makes a wuick jump/change in ohms/volts you found the problem.
Click to expand...

This is where you want to look. At idle you can open the throttle plate all the way if the TPS rod is disconnected and the RPM's will not increase. If the TPS is fine, you will need to hook up fuel pressure gauges to the air rail and fuel rail and take readings when the over rev occurs, 90psi fuel and 80psi air. If readings are off, My next step would be to check the tracker valve diaphragm for holes. This will cause an initial over speed and surge.
 
All good points suggested... but what throws me is that this engine will start, and idle just fine....
Then you shift... without any movement of the throttle arm and its outta control...
 
Exactly.
I'm gonna swap out the TPS tomorrow for one that I know is good....just to eliminate a problem there. Then I'll bypass the shift switch and see if that makes a difference.

Thanks for all the support with this issue. I'll post up my findings.
 
ya if throttle not moving when shifting in gear where is fuel and air comming from tps not moving butterfly not opening how in the world does it rev outta control??? if computer shot air/fuel form compressor/injector should the engine just die over rich??? no air from mechanical butterfly (nothing To do with ECM)
tracker valve hole- never seen that happen// purge some air/fuel from shrader valve is there air in one and fuel in other or is fuel/air form both???
ECM injection pulse width controls fuel delivery and air injection where is getting throttle up signal if not form tps???
JUST SOME OPERATION THEORY THOUGHTS
really like to know the answer to this one!
 
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Opti-man-808 said:
ya if throttle not moving when shifting in gear where is fuel and air comming from tps not moving butterfly not opening how in the world does it rev outta control??? if computer shot air/fuel form compressor/injector should the engine just die over rich??? no air from mechanical butterfly (nothing To do with ECM)
tracker valve hole- never seen that happen// purge some air/fuel from shrader valve is there air in one and fuel in other or is fuel/air form both???
ECM injection pulse width controls fuel delivery and air injection where is getting throttle up signal if not form tps???
JUST SOME OPERATION THEORY THOUGHTS
really like to know the answer to this one!
Click to expand...

When the tracker valve diaphragm fails and a hole forms, the engine will rev to almost 5k rpm's for about 20 seconds, come back to idle and then surge up and down between 3k and 4k.

The TPS is what controls fuel flow. Don't just change it, get a meter and check it for smooth voltage increase. (0.50-0.60 volts @ idle and close to the reference voltage at WOT) The throttle plate can be removed and the engine will not rev until the TPS is actuated.
 
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Well when I removed the TPS the back plate fell out in my hand. The bracket that it mounts to has a hole the same shape as the back plate of the TPS which would allow it to simply come unbuttoned.

Why in the world does the bracket have that cutout? Seems that without the cutout it would assure that the TPS remains assembled.
 
Ok..... I've learned that the TPI bracket used on this model is the same bracket as the one used for models with 2 TPI's (hence the cutout) and the back plate of the TPI is secured merely with RTV silicone. The back pkate of the TPI can walk out and as the core of the TPI begins to fall out the return spring disengages.

I cut out a piece of thin shim stock to go behind the TPI to ensure that this NEVER happens again.

Thanks for all the help guys, really appreciate it. And you might consider installing a shim behind your TPI if it is mounted in the same fashion.
 
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