Exhaust manifold temp. sensor broke off, can I use threading tool? Suzuki DF50

[bobbpopp]

I posted on the Hull Truth about my 2002 Suzuki DF50 and the extremely annoying beep every 5 seconds. I assume there are quite a few DF50 owners here who may have experienced the same.
https://www.thehulltruth.com/boating-fo ... -df50.html

My 2002 Suzuki DF50 had a beep every 5 seconds, and the tach showed the 1-5 code, exhaust manifold temperature sensor. I took the sensor out, and it was broken, about half the sensor is still stuck in the block. I tried screw extractors, but they only shaved some of the remaining sensor material off. The thread seems to be good, so I decided to stop before ruining it. I hand-tightened the new sensor ( 34830-87JA0 ) in, with the o-ring just touching the block, fired up the engine, and the beep is gone. I have not gone over 2,500 rpm, and the engine is working fine.

My question is, since it is the exhaust manifold, can I use a threading tool / tap and die tool to get the remaining material out? Would the debris go out of the exhaust?

[Jimmyt]

If you have a clean entry, and can get the tap started in the correct orientation, sure. But, I can't tell from your pictures what the exact situation is. The trick is getting the tap started correctly in the existing threads. I'd use a shop vac nozzle as close to the hole as you can get out to try and extract as much of the debris as possible - once you get the tap started properly in the existing threads. Debris collection is well below proper thread start in priority.

The other caveat is: should work if the sensor material is not significantly harder than the exhaust manifold, and that there's not a lot of it left in there.

If you have too much material in the bore. You might try a dremel to open the hole up so the tap is only removing threads and not trying to drill through the broken sensor body. It will be delicate surgery, but if you pull it off without having to replace the manifold, it will be time well spent. Again, I'd try to shop vac the grinding dust if possible. You'll probably need an assistant to hold the vac nozzle; as steadying the grinding process will likely take both hands.

Good luck.

[bobbpopp]

Thank you for the suggestions. I have been trying to scrape out some of the remaining sensor with one of those metal picks that dentists use. It seems that every day I get a little more out. I think I will try the dremel in a few weeks if I don't get any additional stuff out.

[Jimmyt]

Picking it out is the safest way to do it. Thought you had more of the sensor left than you could pick out.

If you can pick out a few threads to get the tap started, that would be excellent.

If you have to resort to dremel grinding, go slow and try not to get into the threads. You just need the hole big enough to let the tapered end of the tap through and get the tap started in the threads.

Patience is the key.

[Be Free]

I'm confused. If he can get the new sensor to thread in why won't the tap start?

[Jimmyt]

Pics weren’t clear enough for me to tell what was going on. I was working off of this statement:

[about half the sensor is still stuck in the block. I tried screw extractors, but they only shaved some of the remaining sensor material off. The thread seems to be good, so I decided to stop before ruining it. I hand-tightened the new sensor ( 34830-87JA0 ) in, with the o-ring just touching the block,]

So there is something stuck in there, but I don’t know what. If the remaining part of the old sensor is solid, or has a small hole, the tap won’t do the job - even if there are a few threads at the start of the hole. There has to be a hole at least as big as the diameter at the peak of the threads to run a tap through it and clean it up.

I was trying to describe what to do based on conditions I thought might exist. May have given too much information to be useful in this case.