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Throttle Positioning Sensor

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Old 07-14-2013, 09:29 AM
  #1  
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Default Throttle Positioning Sensor

1994 225TXRS 2 stroke

I checked the TPS and from the readings in the 3.00 to 5.00 range I determined it was bad and ordered a new one.

Well I installed the new one and get the same readings as adjusting it with the two phillips screws does not help.

So I took it off and tried adjusting it by simply turning it with my fingers. I got the reading I wanted, 0.49 as the manual calls for a reading between 0.47 and 0.51.

I put two marks where the pin that goes through the rod is supposed to be. Now hopefully the pics show y'all the problem I am having with setting the TPS correctly.

Front view of bracket that was on boat when I bought it 3 years ago.
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Side view showing the plastic piece with the notch that the TPS pops onto to.
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Here is the problem. When I place the TPS in a position to where the pin can snap into the notch on the plastic piece, you can see how far off the screw holes are to bolt the TPS down.
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Side view shows where the pin on the TPS is supposed to pop into the notch on the plastic piece. With it being so far off, the is no way to adjust the TPS to the specs the manual asks for when it is bolted properly in place.
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Now I remember I had a problem two years ago when I rebuilt my carbs and tried to sync them according to the manual. I couldn't get the correct readings on the sensor. The motor ran and runs, but does act up a lot due to this. So this time while syncing the carbs, I decided to get the TPS set properly.

But now I am wondering at some point before I got the motor that someone might have put the wrong bracket on it?

Here is a bracket picture I found on online that says it is for the '94 to '95 engine and it has three bolt down places as opposed to my two. SO I'm now wondering if it put the holes on the sensor in the proper places to get the right adjustment values for the sensor?

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I am going to try and secure it in the position that the reading on the fluke meter shows to be correct. Then go out and run it to see.

Does anyone know if it is even possible to put a wrong bracket on the motor?

Or what could possibly cause the readings to be so far out of specs that would cause the screw holes to not align up properly?
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Old 07-19-2013, 08:32 PM
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Surprised no one replied, maybe to tricky of an issue? lol!

Update though: I fabricated a plate that bolted to the stock bracket above and put the TPS in a position to be able to adjust it according tot he manual, .47 to .51.

The engine does not like that setting and actually, nothing in that range when I turn the TPS would make the engine happy.

I then removed the plate and just went back to the original position with the TPS and dialed it in at 3.67 which makes the engine somewhat happy. It still tries to bog down when I jam on the throttle in the driveway. Though easing into the throttle does not cause it to bog down.

So I am wondering why my TPS has to be set so far out of range to make the engine happy?

Since the computer sets the timing, not sure which way to go at this point except a mechanic.

Any ideas or has anyone had or seen this issue?
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Old 07-20-2013, 05:18 AM
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Where are you located ?
You can ask for rodbolts advice on boats.net


Oops he already responded....
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Old 07-20-2013, 07:17 AM
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Sunds like your TPS is out of spec and needs to be replaced

Does the manual state there is an adjustment that can be made or are you trying to meet a spec by just fooling with it?
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Old 07-20-2013, 07:35 AM
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Ok,I'll play...The tps shaft will rotate all the way around.Try rotating just the shaft 180 degrees and installing the sensor on the mount.Take readings and see if you can get the throttle closed setting adjusted to spec.
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