Suzuki 140 issues

[SDUB407]

I have a 2003 Suzuki 140 df. While running when i put the throttle down it will run up to 3k rpms then goes into limp mode. I am not getting any codes... i can put it back into neutral and slam it in gear and it runs out fine until i let back out of it and get under 3k... i have some ideas but any help is appreciated. Thanks.

[catacom225]

First thing to confirm the engine holder has not corroded [ search this site or google [ DF140 engine holder corrosion ] or try running without the hood on, excessive gas leakage could be starving the engine of clean air

[SDUB407]

I have done both all good there. Runs same with hood off as on. Replaced pickup, siphon valve, all fuel lines to motor, cleaned vst, throttle body, new plugs, cleaned iac valve and still same results. Im leaning towards possible neutral safety switches.

[redlowrey]

Have a look at the switch on the engine, there might be too much grease near the blade stopping it from working properly or it’s faulty.

[SDUB407]

Thanks ill.give it a look.... do you know if there is a way to check it with a meter? If so how?

[SDUB407]

Update. I have had a new water pump and 2 temp sensors replaced and still having same issues. Sometimes it goes into limp mode right off the trailer. Can pull it back into neutral and then push it back into gear quickly she runs out fine with no issues. Its like its tricking the ecu. Any one have any input? I have also seen the 3-2 code off and on but then it goes away. Will it put engine in limp? Thanks

[redlowrey]

Mate what are you doing, I told you a month ago where to look, what ever made you replace both temp sensors and the water pump, you have already given the answer to your problem in regards to your shifter with the switch on the engine.
What is happening in neutral, the computer is seeing zero volts, so it puts a ground on the starter relay and grounds the injectors allowing the engine to start, when you put it into gear it is still seeing zero volts on pin five instead of 2.5 volts so it will fix the timing and rpm to around 3000 rpm. no codes.

As far as the map sensor goes nothing to do with the neutral switch, I do all checks at the computer.

[SDUB407]

I carried it to a mechanic who put it on a computer. The computer sbowed over heat issues so they swapped out those parts. It needed an impeller. I have had tbe intermittent code of 3-2 then it will go away. Im going to look into the neutral safety switch just dont want to be changing alot of parts and it not be the issue.

[Moonlighter]

Listen to Red.

As he says the neutral throttle switch in the engine. May be loose or failing.

Switch is located on the gear linkages on the starboard side.

This switch tells the ecu when the engine is put in gear. If the ecu doesnt get that signal, it will limit revs to about 3000rpm and restrict spark advance and fuel supply, so the engine will feel doughy and will miss and fart if you push it to try to exceed 3000rpm.

The switch is not difficult or expensive to replace, If you use the BUY SUZUKI OUTBOARD PARTS link in the blue bar near the top of this forum you can find your year and hp engine and find the part number and cost. And see an diagram of where it fits.