Suzuki 140 Neutral Safety Switch location

[Moonlighter]

I was just reading this post and was going to reply by saying that your problem has got nothing to do with the neutral switch. Early engines had what they called a closed throttle switch that would inform the computer when the throttle was in neutral and depending on temperature would control the amount of air bypass and ignition timing so the engine did not stall.
Your engine has a variable voltage throttle position switch to inform the computer at what position the throttle is at any position, so when you pull back on the throttle it will monitor the timing and air bypass so the engine don't stall, your symptoms sound like iac valve problems, but I would do other checks in the system before you spend more money. That fuel pressure seems high, I think there are other problems besides the iac. Does it run smooth when it is cold or a little rough,
Very poor service from the Suzuki dealer, they cant even diagnose a simple problem.

Hi Red!

I notice in the first post he says its a 2013, so that would make it a A series engine.

I know a few people who have had IAC issues with 115/140 A series engines, one even had a shorted IAC that took out the ecu - Suzuki dealers in Au would have heard of that one I imagine.

[redlowrey]

just reading my post I should have said the computer knows when the throttle is closed with the closed throttle switch instead of neutral. That's right a simple resistance test will check that, the valve shouldn't pull much more than one amp, between 8 and 12 ohms with the plug disconnected. Mate if have not got skills in voltage drop testing, and the problem is electrical it will be hard for you to diagnose your problem.
So what you are saying in that last post is when the engine is cold it will start and run good at wide open throttle but when it is hot it starts to play up,and if you open the throttle quick it over comes the flat spot and does not stall.
Do you know how to use a digital multimeter if so, disconnect the plug on the iac valve and check the resistance between the two pins. A little bit of history would be handy like how long you have had the engine, how long has the problem been has there, did it used to run good.

[buyslake]

I took off the IAC, and sprayed it with carb cleaner inside and air compressor air clean. put it back on and still same problem. Motor runs fine at idle but soon as I put in gear it dies. I see the new IAC is ~$300.00

Not sure if I should purchase new IAC or ? I don't really want to bring it back to that dealer as they don't seem too know what they are doing.

[buyslake]

just reading my post I should have said the computer knows when the throttle is closed with the closed throttle switch instead of neutral. That's right a simple resistance test will check that, the valve shouldn't pull much more than one amp, between 8 and 12 ohms with the plug disconnected. Mate if have not got skills in voltage drop testing, and the problem is electrical it will be hard for you to diagnose your problem.
So what you are saying in that last post is when the engine is cold it will start and run good at wide open throttle but when it is hot it starts to play up,and if you open the throttle quick it over comes the flat spot and does not stall.
Do you know how to use a digital multimeter if so, disconnect the plug on the iac valve and check the resistance between the two pins. A little bit of history would be handy like how long you have had the engine, how long has the problem been has there, did it used to run good.

I purchased the motor new in 2013. It is a DF140A 4 stroke It has only been used in fresh water. The problem started a few weeks ago. It has always had a strange issue since I owned it where if you ran across the lake fast then dropped throttle quickly it would always die. Then I would just restart it and it seemed to run just fine. It only died if I ran it hard and stopped quickly. Maybe that issue has just got worse now? It runs fine in idle but soon as I put it in gear it dies. So I have to gun it real fast to bypass the slow throttle area to get it to go, then it will run fine at high speed but soon as I slow down back toward neutral it dies..

I do have a multi-meter. I unplugged the IAC and set the OHM meter on 200K setting and tested the IAC pins and it reads 60, I changed the meter dial to 20M and it reads 6.

[Moonlighter]

When it dies, is the fuel primer bulb flat or soft?

[buyslake]

Good news, Motor problem is gone. I took it to the lake after cleaning the IAC and used it for about 15 minutes running time and the problem was still there. I then threw it into reverse at good speed to keep it from dieing and I was going in reverse for about 5 minutes ihen I went back to neutral and it did not die which was the first time I was able to go to neutral in a long time without it dieing. Then I put it in forward at slow speed and it did not die. Now the motor is running great and it does not die anymore. So maybe cleaning the iac created benefit and it just took a some running in reverse to free up the IAC to function properly?

Thanks for everyone's help!!