DF 140 Questions..........?

[AKjohn]

I finally got around to doing the yearly inspection and maintenace on my 2003 140 four stroke, I was looking down the list of items in the workshop manual and two things came up that I have not done in the past.

The motor has ~300 hours on it and I have never set or checked the IAC valve, is this a big deal? The motor starts, idles and runs fine?

The second thing is, it says to check the "timing belt", now I know this motor has a timing chain with a automatic tensioner. I can understand the book may have meant to say chain, but is there a way to inspect this externally?

Also why does Suzuki offer two T-stats for this motor?
I have been told to use the 60C one by the local dealer, I am in AK and the water is plenty cold so am thinking I could use the 71C......?
I do run a jet pump on it most of time.

Thanks, John

[WEDOCQ]

John,
I am not a mechanic, but have just completed a major overhaul on my DF140, so I feel like I know it well. The IAC valve controls the air flow when the motor is in nuetral. It's what sets the idle speed. Unless you having idling problems, I see no reason to check it other than maybe making sure the tube isn't clogging up.

As far as the timing chain goes, from the research I did, Suzuki made this chain to last the life of the motor. When I put my timing chain on when I put the motor back together, there was no way to adjust it once it's on. Also, to inspect the timing chain, you would need to remove the powerhead from the engine holder, to get a full view.

Now to move on to way more important issues. Have you replaced your engine holder plug? Just do a quick google search on "Suzuki engine holder corrosion". Hours of fun reading. Long story short. Suzuki placed a plug on the port side of the engine holder in anticipation of using it for an O2 sensor in the future. No O2 sensor ever came, but the soft metal plug they used has cause a lot of problems. The dissimilar metals starts the corrosion process. It eventually will eat thru this plug area as in this case:
Suzuki DF140 "engine holder" corrosion fix! - The Hull Truth - Boating and Fishing Forum

Sometimes, the cancer corrosion will eat thru the exhaust walls of the engine holder first, before any problems occur with the plug. This can cause a multitude of symptoms including: water in the exhaust, exhaust in the crankcase, water in the crankcase, etc. This is what my engine holder corrosion looked like on the inside:


So what I would do is remove that plug ASAP and replace it with an aluminum one. To do this you might need to get creative. The plug is an 18mm by 1.5 thread. Hard to find. I had a machine shop make me one.

If you are not up for this task, I would at the very least watch very closely for water getting into the oil. This will be a sign things have gone south with the engine holder. Another common reason for water in the oil is a corroded seal on the water cooler of the engine filter holder.
Good Luck,
Shawn

[AKjohn]

Shawn,
Excellent information, thanks for the reply.
I removed the cowling today and everything appears just fine, but I did read all the posts in "The Hull Truth". Rather amazing, I have read several post cocncerning 140's "maikng oil", this sounds like the cause.

Is this plug strickly into a exhaust cavity or water jacket also?
I usally run the boat in fresh water but it sounds as if this issue is not isolated to salt water. I do remove and clean the internal anodes.

It sounds like some folks could not remove the plug, but apperently you were able, any thoughts regarding removal?

John

[WEDOCQ]

Another guy said he used liquid wrench and then it came out no problem. I had to drill mine out, which pretty much sucked. This plug is on the engine holder on the port side. It accesses the exhaust excusively. BUT, the cancer it causes can spread to areas that affect water jackets, and/or allowing exhaust in directly to the crank case. This problem seems to affect everyone eventually. I just think it's the conditions the motor is run in. I have see motors with 3000 hours with this problen, and motors with just 300 hours with this problem. I guess it just depends. This is a real good motor. It just has one small flaw that Suzuki doesn't want to recognize. Thank God we did!!!

Shawn,
Excellent information, thanks for the reply.
I removed the cowling today and everything appears just fine, but I did read all the posts in "The Hull Truth". Rather amazing, I have read several post cocncerning 140's "maikng oil", this sounds like the cause.

Is this plug strickly into a exhaust cavity or water jacket also?
I usally run the boat in fresh water but it sounds as if this issue is not isolated to salt water. I do remove and clean the internal anodes.

It sounds like some folks could not remove the plug, but apperently you were able, any thoughts regarding removal?

John

[AKjohn]

Debating whether or not to remove this plug, I think once I attempt to remove there will be no turning back....

I spoke to my local dealer here in Fairbanks and he feels corrosion has not been a issue here, maybe due to the typically colder water and may be more fuel related as we do not have to contend with ethanol based fuels.....

Suzukis arent the only ones having problems.....I have gotten on a local forum and no one seemed aware or interested in this........still pondering.....

[pattcook]

John- Shawn convinced me to check my internal anodes and remove the steel plug. Glad I did. Anodes were completely gone. 400 hrs on a 2002 df115. Should have checked yearly. Got the steel bolt out with some liquid wrench. I could see and feel where the internal threads were corroding down. I had a 18mm 1.5p plug made at a machine shop. Not cheap. About one hours labor. Since then I found a cheap source for the plugs. A manufacturer of aluminum oil pan plugs has one for five bucks and shipping. You have to order from the guy direct so he can get you one before they magnetized it. 1-888-578-3851. Ask for Tim. I suspect like Shawn most of these motors will have problems to some degree. I feel a lot better with that steel bolt out. I just hope its not too late. good luck - John

[DolphinDog]

Suzuki problem Plug

I have twin DF115s ( same as DF140 block) and great motors

The exhaust plug is a PAY NOW or PAY BIG TIME later issue.

Even if you have not had problems yet great post here.

I had one welded closed and it worked, welder charged me $150 well worth it. And the other one I used a hand held torch to heat up the area around the plug and gently removed it. Once it started to come out any resistance I would re heat the area as to NOT BREAK the aluminum. It worked.

There is a guy in Montana who sells the plug on ebay g o l d anodized alum plug with aluminum washer ( do not use steel) G o l dPlug.com

Suzuki DF140 "engine holder" corrosion fix! - The Hull Truth - Boating and Fishing Forum

I have water in the oil and on the threads here to figure out how to remove the power head so I can take it into a shop.

DolphinDog

[noelm007]

Just to be VERY clear here, the steel plug is a left over from the car the motor was sourced from, there was never a plan to fit the 02 sensor on the outboard. The plug is also on the DRY part of the exhaust, no amount of flushing will prevent it corroding, while you are doing this maintenance, a 140HP has an oil cooler that is prone to failure (well the O rings are) and this will give you water in the engine oil, make sure it gets serviced regularly.

[nelbur]

I would remove the plug for peace of mind. It may not be a problem in fresh water, but the area behind the plug appears to be where water and exhaust mixes. Mine was not removable with the internal hex intended to be used. I just drilled the plug with a 1/2" bit. When the bit bottomed out in the hex and slowed down, I drilled through the rest of the plug with a 1/4" bit, and switched back to the 1/2" bit to finish up. At this point you may be able to unscrew the remaining portion using a cold chisel and hammer to knock it around. I had to use a metal cutting jig saw blade in a visegrips to cut slots in the remaining portion nearly to the threads, before I could unscrew the remainder. The aluminum plug can be ordered as mentioned from g o l dplug.com (eliminate the spaces as this forum doesn't like the word g o l d).

[Vsyyuuwyewr]

It’s really great posts