View Full Version : Throttle position sensor? Or something else?

06-04-2014, 12:03 AM
Hello all. I am from MT and just bought a new to me mastercraft from a private party that has been a nightmare. Could anyone please tell me what this loose wire is and if it is supposed to be hooked up? Its on the starboard front of the motor of my 2001 x-10 w a 330 horse 5.7 indmar vortec. I just had a massive amount of work done to it at the mastercraft dealership(all new motor/tranny mounts, fuel tank and steering cable which consisted of pulling motor and tranny) due to the previous owner to the tune of 11,700.00. I have about 5 hours on it since the rebuild and there is 410 hours on the boat. The reason I am mentioning this stuff is because last time I had it out and we went to start and take off from I would turn the ignition over and nothing. When it did finally crank over with out starting was when i wiggled the throttle lever. It finally started when I hit the middle button and gave it some throttle in neutral, but then when I went back to neutral to reingauge the transmission it immedietly died. Same thing happened two more times. Then the third time it didnt do it and ran, but when I looked at my temp gauge it read as cool as it would go, and we were probably only relaxing for about an hour. It had been reading heat earlier in the day. I spent quite a bit of time searching around the boat for anything loose when I got home. Good volts from the batt, they replaced the key switch, I took the starter out and had it checked just to be sure and it was good. From reading on here I am leaning towards replacing the kill switch and TPS? The kill switch does seem a tad loose but i do have all my dash board lights when its in place and I threw a little black tape on it for now to make it a little more solid. Also can i just grab a TPS from the local auto parts store for a 2001 5.7? And does anyone have a part number?

One more thing, once I got it back from the dealership going foreward with the throttle takes quite a bit of umfff, to the extent were the panel moves some. Going back is perfectly fine. I thought there would be an adjustment but I took it all apart and found nothing. When I loosened the little angled allen set screw inside did nothing and there seem to be plenty of grease on it. I thought maybe the throttle linkage may have got kinked when they took the motor out but reverse is just fine and its pulling the cable just the same.

Any help or recomendations with this stufff would be greatly appreciated. Thanks in advance and look foreward to being on this site!

06-04-2014, 12:11 AM
Contact Bruce at Action Water Sports. He should be able to help.

Jeff d
06-04-2014, 07:11 AM
I've had the opposite throttle/shift cable binding issue before. It was after I had removed/reinstalled the kick panel at the driver's feet. Upon reassembly I put the cables in a little bit of a bind and it made moving it into reverse difficult and rough. The cables didn't really look like they were in any kind of a bind but when I removed the kick panel again and the problem went away. I just had to put it back together in a manner that didn't bind them and haven't had the issue since.

What's the picture supposed do show? It looks like the oil pressure sender for the gauge (there's a different oil pressure "switch" for the ECU) but the oil pressure sender is normally on the top, starboard side of the engine.

Jeff d
06-04-2014, 07:38 AM
I've never had a bad tps on a boat but I did have one on a car before. The behavior I saw there was that it would start and idle fine but then when I drove it it ran like crap and the rpm was all over the place. You can test it with a multimeter. It's just a variable resistor that you can probably find the appropriate range for the open and closed positions on here somewhere.

06-04-2014, 08:20 AM
motor mounts? fuel tank? yes you can grab a TPS at the local parts store. Is this a TBI? regarding start - I would check neutral switch position on trans.

You may have to inspect the throttle to see if cables or controller needs lubrication or work.

Jeff d
06-04-2014, 08:33 AM
Is this a TBI?
If he's citing is "330 horse" number correctly then it's an LTR right? Isn't the TBI 310 hp?