TPS ?'s

[Blown Up]

What are the symptoms of your TPS being out of adjustment? Will the motors still make make enough power to run full rpm's? Will it only affect idle?
Cause gas usage to go up?
Just trying to learn the different effects an TPS being out of adjustment can cause, nothing specific to my boat. Outboards are still somewhat new to me and always looking to learn more about them for my own personal knowledge.

Thanks.

[Liberator*21]

If you have a low idle sneeze, your TPS will probably be set to the lean side. If your smoking allot or see excess soot on the prop you may be set a little to rich. TPS will play a big part in either of these.......................

[Tony Brucato]

What are the symptoms of your TPS being out of adjustment? Will the motors still make make enough power to run full rpm's? Will it only affect idle?
Cause gas usage to go up?
Just trying to learn the different effects an TPS being out of adjustment can cause, nothing specific to my boat. Outboards are still somewhat new to me and always looking to learn more about them for my own personal knowledge.

Thanks.

It depends on the engine model. Mercury 2.5 liter XRI or laser injected motors, the TPS only has an effect on fuel delivery up to about 3500 RPM.
On Mercury 3.0 Liter EFI motors, the TPS effects both fuel delivery and ignition timing through the entire RPM range.

[Blown Up]

I was more intersted in 3.0 L EFI motors. That is what myself and my friends have.

If the TPS is off, will the motor still make enough power to turn full rpms or will it just run like crap?

[Knothead]

It depends on the engine model. Mercury 2.5 liter XRI or laser injected motors, the TPS only has an effect on fuel delivery up to about 3500 RPM.
On Mercury 3.0 Liter EFI motors, the TPS effects both fuel delivery and ignition timing through the entire RPM range.

What is the proper procedure for setting the TPS? My '95 200 Pro Max seems to run rich at idle/lower RPM's, but runs like a scalded dog at higher RPM's. 3500 RPM is about where it starts to clean up & run well. I've been thinking maybe it was the low side of the stator going out. I have a lot of sooty buildup on the prop......

[Liberator*21]

If the TPS is set toward the rich side, that will effect your top end, but it would also effect your bottom end due to a rich idle since it's set rich (if that's the case). Make sure you've got a good set of injectors working for ya, that can also limit top end because of less flow or not properly atomized fuel...............nobody said it was simple.............LOL, good luck.

[Knothead]

I'm not having any problem at top-end, just seems to idle rich/smoke a lot. Also have the sooty buildup on prop. Seems sorta "boggy" at lower RPM's, but will turn a 25 Tempest to the limiters at top-end. This is on a '90 Allison XTB21.....

[Liberator*21]

The bottom line is unless you know what your TPS is doing, you really won't know anything for sure. The biggest problem with the early 3.0L EFI TPS is those damm cheap rubber bushings. Just because you set it correctly today doesn't mean it'll be that way next week. I replaced all mine with bushings I made from Nylon/Delrin , it's a hard plastic that will take the heat under the hood and never flex, set it and forget it (until it totally fails). First off you must make sure that your TPS is functioning correctly, idle to WOT, smooth increase in the numbers on a DDT as you open the throttle. A DDT is the best way of validating your TPS. On my mod'd 225 EFI & 250 EFI I always set it at 1.05-1.1 @ idle. Ya, it's a little fat over OEM setting but it liked it that way. There is a harness that Merc sells where you can check/set your TPS using a Digital Multimeter. I have one for sale one the boards, I think it's for a 3.0L. This is allot cheaper than $800 for a DDT, but in either case you have to know that your working with a good TPS and then work outward from there.

[Liberator*21]

In regards to the 3.0L EFI TPS...........

The bottom line is unless you know what your TPS is doing, you really won't know anything for sure. The biggest problem with the early 3.0L EFI TPS is those damm cheap rubber bushings. Just because you set it correctly today doesn't mean it'll be that way next week. I replaced all mine with bushings I made from Nylon/Delrin , it's a hard plastic that will take the heat under the hood and never flex, set it and forget it (until it totally fails). First off you must make sure that your TPS is functioning correctly, idle to WOT, smooth increase in the numbers on a DDT as you open the throttle. A DDT is the best way of validating your TPS. On my mod'd 225 EFI & 250 EFI I always set it at 1.05-1.1 @ idle. Ya, it's a little fat over OEM setting but it liked it that way. There is a harness that Merc sells where you can check/set your TPS using a Digital Multimeter. I have one for sale one the boards, I think it's for a 3.0L. This is allot cheaper than $800 for a DDT, but in either case you have to know that your working with a good TPS and then work outward from there.