2005 DF140 issues

[slayray]

Hello! This post has been a longtime coming as I had to create a new account because I never received an activation email. Anyways thank you in advance!

I have a new to me 05 DF140 (I've put about 200 hours on the motor), the motor runs like a champ! But there are a few issues, performance wise it will die if i come down off of plane and into neutral too quickly.

I was able to secure the suzuki diagnostic software and saw that some old codes had an overheat issue. Previous owner didn't mention this but mentioned he had to replace the IAC valve due to engine dying coming off of plane quickly. I noticed I had this issue a few times but as long as I slowly slow down and let the engine recover it won't die, (CTP switch?). I also noticed that the low pressure fuel pump was leaking oil and under more inspection it was missing an O ring so I added one and problem fixed no more leaking. On top of the engine I noticed what looked like a sensor (I now know its the cylinder temp sensor) was hanging and zip tied to the engine lift to stay out of the way. The hole that it came out of looks like it was stripped but now I'm thinking it melted and snapped off! I also noticed that the air silencer was barely hanging on and is missing a bolt on the port side and another bolt snapped off on the forward facing side. Upon removing the silencer I noticed a disgusting amount of what I think is dirt and oil almost turning into a soil type consistency all on the throttle body and plate. Inside the silencer looks even worse...
Every time I take off the cowling the engine smells like raw fuel as if it is leaking from somewhere (I couldn't find any visual leaks). Also am suspicious that my engine is making oil as I triple checked the level after oil change and now I am bit high on the dip stick. After reading many threads on the corrosion plug on the engine holder I inspected that and it looks very rusty. The only symptom that is telling me that the engine is perhaps running funky is the fact that it dies sometimes after coming off of plane (but quickly starts right back up) and also what seems to be low battery voltage. If I recall correctly my SDS said my voltage was around 12.8 V. I have a dual battery setup with an ACR that seems to kick on intermittently barely charging my house battery. I just had to replace a 1 year old house battery because it had some dead cells. I just purchased a new battery and onboard battery conditioner to hopefully mitigate some of these issues. Also noticed my kill switch works but doesn't turn off the engine. I have chased the ground wire all the way down to the harness but dont see any issues. Its driving me crazy not being able to reset the oil change alarm. Overheat damaged harness at engine maybe?

I have a strange feeling that an overheat may be causing a lot of these issues. I would like to try the cowling test to see if Im getting any exhaust from the corrosion plug area making my engine run lean and hot. I plan to look at IAT sensor and see if that changes with cowling on/off and within range when on. I also think I notice a bit of browning on the wire leads from excessive heat around the rectifier/regulator pig tail but not quite sure if thats the case.

Is it possible my rectifier regulator is damaged or perhaps the wire?
How would I go about retapping a new hole for cylinder temp sensor?
Are there any correlations that you are seeing that I'm not? (very likely)

Proposed Actions
IAT sensor readings on SDS cowling on/off
resistance tests on magneto and rect/reg
Clean silencer, throttle body, intake manifold really well
While I have the silencer and everything off also take a look at VST and associated components

I would really appreciate any insights and guidance to fix my charging problem and also fix any potential time bombs going on in the engine. (I am sure not having a cylinder temp sensor could be a huge problem in the event of another overheat condition)

Thanks in advance!

[Murray]

For your regulator/rectifier measure the output voltage on the battery. It should be around 14.5 volts, check with the engine cold then test with a hot engine. My engine (2009 DF90A) can’t be checked with a multimeter, Suzuki requires a “Suzuki pocket tester” check your service manual.

[slayray]

For your regulator/rectifier measure the output voltage on the battery. It should be around 14.5 volts, check with the engine cold then test with a hot engine. My engine (2009 DF90A) can’t be checked with a multimeter, Suzuki requires a “Suzuki pocket tester” check your service manual.

Thanks! I assume I should be checking the engine battery isolated correct?

[redlowrey]

What Murray means is with the engine running, the most important thing to do is clean the throttle body housing and throttle plate especially the under side of the plate and pull the temp sensor out and have a look to see if the sensor housing goes through to the water jacket or bottoms out.

Early systems went through to water late systems bottomed out, very important sensor, it needs to be screwed in firm to be able change in resistance to the changing water temp.

You should be able to watch your sds for the closed throttle switch, when you open and close the throttle it will tell you off or on.

[Murray]

Your starting battery, assuming thats where your regulator/rectifier output goes. I only have one battery so in my case it’s a no brainer.

[slayray]

What Murray means is with the engine running, the most important thing to do is clean the throttle body housing and throttle plate especially the under side of the plate and pull the temp sensor out and have a look to see if the sensor housing goes through to the water jacket or bottoms out.

Early systems went through to water late systems bottomed out, very important sensor, it needs to be screwed in firm to be able change in resistance to the changing water temp.

You should be able to watch your sds for the closed throttle switch, when you open and close the throttle it will tell you off or on.

Hey Red. Unfortunately my temp sensor is snapped off looks like the bottom part of the sensor is stuck in the hole. Should I drill out and retap? Whats the process you would you use? Thanks

[redlowrey]

Be careful if you have the late type of sensor it screws into a blind hole, and you might drill into the water jacket.
Did all the threaded part of the sensor come out, Buy a new sensor and you will be able to determine how much is still in the head.
You will be able to see how far you can drill with out causing a problem.

[slayray]

https://drive.google.com/file/d/15Ql...w?usp=drivesdk

here is a picture of the broken off threads of the sensor. Looks like a new sensor was already bought but never installed due to broken threads. The first half of the hole is smooth which matches up with the smooth part of the sensor then a hard stop where threads line up.

would you recommend doing a center punch, drill, and bolt extractor? I don’t wanna hit the water jacket like you said Red.

[redlowrey]

I can't up load the picture, I would try and get it out with an easy out the only downside is as you screw the extractor in it will tend to spread the case of the sensor in to the thread.
I would try that first and I would soak the hole with penatriene for a week first, some of it might get down past the threads.

[slayray]

I can't up load the picture, I would try and get it out with an easy out the only downside is as you screw the extractor in it will tend to spread the case of the sensor in to the thread.
I would try that first and I would soak the hole with penatriene for a week first, some of it might get down past the threads.

Hey Red, I updated the permissions to the picture. Okay if I try the extraction method and it doesn’t work what then would you do? Drill and retap?

[redlowrey]

I can see it now, measure to see how much you have got to play with, let it soak for a week. The only trouble drilling and tapping if you don't get the center punch central you will drill off into the thread.
I think the inside of the sensor might crumble as you extract, see how you go if it crumbles just use a bigger drill and keep going to the wall trying not to damage the thread.

[slayray]

Okay Red, just like you said it started crumbling. I got multiple size extractors in with no luck the metal was too maleable. The good thing is i got a good center for the drilling. I am currently using a 1/4 bit and feel like thats as large as I can go before the threads start being affected. I was able to get about 1/2 the diameter for the first thread out but the thread doesnt look clean and distinguishable. Underneath it looked like salt in the thread groove. I am using a small pick to run through the thread but its just not strong enough.

Should I go up in diameter bit? Or start a tap?

I can see the finish line I just don't wanna screw it up.
Thanks again for all your help.

[redlowrey]

If you think there is enough to take out without hitting the thread go for it, you might be able to go from an imperial drill bit to metric EG, 3\ 8 is 375 thou 10 mill is 400 thou, 25 thou difference in diameter, 5\16 is 312 thou 8 mill 320 thou, if you get the drift.
I don't have an old sensor laying around so I don't know if they are a gas thread or a fine metric thread, if it is gas I could be NPT, or bsp, try to use an intermediate tap first it will have enough taper on to get started then your plug tap.
It is a very important sensor and it needs to be screwed neatly into the head to transfer the heat into the sensor to change the resistance accurately.

[slayray]

Well bad news. I tried to use a tap but it kept going in crooked. My sensor gets tight pretty quick and have about an 1/8 inch sticking up before being fully seated. What are your thoughts on drilling a bigger hole and doing a thread insert? I would think that would screw up the surface contacting the top smooth part of the sensor. Unfortunately it does not seat nicely like I would have liked it too.

Anyway I could run SDS and see if it’s acting correctly? I’m bummed I wasn’t able to get it to seat flush.

[redlowrey]

If you got it to screw in a few turns and it is tight leave it, if your thermostat is working correctly it will come down below 1 volt at operating temp.