White Smoke😑

[3ric]

I have a 1985 Suzuki dt65. It is barely running. It starts with the throttle lever up and then will idle very rough and smoke (blue smoke). But when I put it into gear or accelerate, it will die and produce lots of white smoke. Then it won’t start again for the rest of the day. I looked at the plugs and the bottom cylinder plug appears cleaner than the other two. I am concerned I have a water leak.
A. Does anyone concur about the water leak?
B. Is the water leak in the head gasket or are there other possible gaskets that could leak water?
C. Still assuming water leak, are there tests to determine where the leak is?

 

[dingbat]

Leaking head gasket….
Replace and go from there

 

[3ric]

Leaking head gasket….
Replace and go from there

Do you think I need to replace just the head gasket or both the head gasket and head cover gasket?

 

[dingbat]

Do you think I need to replace just the head gasket or both the head gasket and head cover gasket?

Head cover gasket?
Only one gasket that I’m aware of unless the block has removable jugs.

 

[3ric]

Head cover gasket?
Only one gasket that I’m aware of unless the block has removable jugs.

Not sure what you mean by removable jugs? When I remove the head bolts, they hold in place (in order) a head gasket, head, head cover gasket, head cover.

 

[99yam40]

I have the feeling dingbat, has never worked on a motor this big before

 

[Sea Rider]

That's a 36 year oldie 2 stroke motor, if wanting to run as when out of the box will need to remove the crankcase Off pan and replace the exhaust eover, cylinder gead, thermostat and bottom pan's gaskets for new ones, proper time to manually scrape clean all water passages, decarbonize the exhaust cover's internal chamber, piston heads and internal cylinder head. Gaskets does not last that long in good shape, much worse if have never ever been retorqued back to fact specs from time to time.

If your motor was run in salt water expect to break bolts which can be removed at a machine shop and if the bolt's threads are stripped can install Helicoils or Timeserts with new same diam and size bolts. If the spark plugs have a dark brown color with adherence seen on the tip it's a clear indication of water intrusion. will also see white lines formations around the exhaust cover and head gasket contours specially if run in salt water. As a comparison, this is a Suzy 40 DT motor with severe gasket's issues...​

This motor has not been flushed with fresh water since out of the box as lives bolted to a large tender boat which lives in salt water. it's an extremely overheated motor due to too much salt sclerosis build ups on the entire cooling water passages which has hardened all possible surrounding cables, the funny issue is that runs with no thermostat which has been removed moons back "to cool better". Will it be fully repaired, definitely not due to Suzy dealer being out of business with no required spare parts availability whatsoever...

Happy Boating​

 

[Sea Rider]

Adding more fuel into the fire :

A year ago the crankcase was removed from pan and partially stripped open, check the highly salted exhaust upper and lower covers and the lower crankcase awful salted condition, now with a ton more salt contents, pics speaks for themselves....​

Now imagine what salt water does on larger HP unflushed motors...

Happy Boating​

 

[Faztbullet]

What has salt build up have to do with original post of rough running and smoke? 3Ric the plug being cleaner could be a problem...run a compression test first.

 

[99yam40]

and then a leak down test to see if combustion chamber is leaking into the cooling system.(head, head gasket etc)
could be in the exhaust, but not likely

 

[Sea Rider]

To start with the OP should have posted pics to show the current state of his motor's condition to have an overall idea of what looks like after long 36 years of use. Wild guessing the current motor's codition without pics will take you to nowhereland.

To rule having spark plugs issues install new ones in well gaped to factory specs and check if the motor runs same. If keeps running like crap perform a compression test to check if all cylinders achieves even or near even compression numbers which are stated in the Service Manual.

Hardened, dried, burnt exhaust cover and cylinder head gaskets can and will leak water in and motor will not run properly. Slow leaking head gasket will not show compression variations, a fully blown one will.

If you think that salt built layers or crusts already built inside the whole water cooling system after boating with such an oldie motor for long 36 years of use doesn't affect all gaskets conditions you're blind. You guys love making partial motor fixes to get out of trouble while neglecting other important areas the motor works associated with that won't last long and will fail anytime soon. A long term used motor as this one needs to be fully serviced as a whole unit and not partially serviced if the OP plans to keep counting with it in top running cond for many more years to come...

Happy Boating​

 

[Faztbullet]

Not all motors run in salt water..

 

[3ric]

Thanks everyone for your input. I did a compression test and it is the same as it has been over the year and a half I’ve had the motor, 140-145 on all three cylinders.

The motor is in great shape for its age. I have never had it in saltwater, but I did check the thermostat at one point and noted that it had white buildup inside. Not a lot, but more than other freshwater motors I have had. I don’t know if this is here or there, but it did not taste salty. I can try to get some pics posted tomorrow.

So for a next step, is a leak down test the next move? Even with the compression otherwise reading good. I have never done one before, but google says the get piston to TDC and compress with 5 psi and listen for leaks?
I don’t know if this is helpful, but I had been trying to get the oil injection to work properly, and in doing so had been running the premix in addition to what was coming out of the injection lines for a good part of the summer, so double oil. I eventually gave up on the injection and went to just premix. This problem started shortly thereafter. But I think it was actually developing before the switch as it would stall at idle and in reversed randomly at first, then more often.
Again, thanks everyone for the help!

 

[99yam40]

blue smoke and running rough would be what I would be chasing not water right now.
unless you find signs of water in the cylinder or on the plug itself.
white smoke after it dies, I am not sure what that is.
steam I would expect while it is running if water was getting into a cylinder

 

[Sea Rider]

As the title reads, where is the white smoke comming from, thru the prop, peeing port, any other water port located at rear of middle leg if having one ? Does the motor pees strong thru those mentioned ports when flushed with muffs while running ?

If a motor runs on salt water for long years will be found inernally salted, whereas same motor run on fresh water will de found scaled. Both situations are due to endless on/heat, off/cold harmfull repetitive cycles which can't be avoided till all motors runs in a future cooled with the kyrpto geen stuff used on non water sports motors.

The white stuff found on the thermostat accounts for that, inspect with flashlight the thermostat's internal housing, it it same or worse than the thermo cond found ?

Asside from cooling issues, the motor may already have developed other mechanical or electrical issues that will need to be correctly troubleshooted if wanting that motor to spring back to life running strong specially at wot.

Happy Boating​

 

[3ric]

Thanks everyone for your input. I did a compression test and it is the same as it has been over the year and a half I’ve had the motor, 140-145 on all three cylinders.

The motor is in great shape for its age. I have never had it in saltwater, but I did check the thermostat at one point and noted that it had white buildup inside. Not a lot, but more than other freshwater motors I have had. I don’t know if this is here or there, but it did not taste salty. I can try to get some pics posted tomorrow.

So for a next step, is a leak down test the next move? Even with the compression otherwise reading good. I have never done one before, but google says the get piston to TDC and compress with 5 psi and listen for leaks?
I don’t know if this is helpful, but I had been trying to get the oil injection to work properly, and in doing so had been running the premix in addition to what was coming out of the injection lines for a good part of the summer, so double oil. I eventually gave up on the injection and went to just premix. This problem started shortly thereafter. But I think it was actually developing before the switch as it would stall at idle and in reversed randomly at first, then more often.
Again, thanks everyone for the help!

blue smoke and running rough would be what I would be chasing not water right now.
unless you find signs of water in the cylinder or on the plug itself.
white smoke after it dies, I am not sure what that is.
steam I would expect while it is running if water was getting into a cylinder

I think the blue smoke might just be a combination of a cold two stroke that was designed to have a variable rate oiler but now runs on premix smoke and maybe a little extra because it’s not getting complete combustion. As it is faint at first and really only smokes as it dies.

 

[3ric]

As the title reads, where is the white smoke comming from, thru the prop, peeing port, any other water port located at rear of middle leg if having one ? Does the motor pees strong thru those mentioned ports when flushed with muffs while running ?

If a motor runs on salt water for long years will be found inernally salted, whereas same motor run on fresh water will de found scaled. Both situations are due to endless on/heat, off/cold harmfull repetitive cycles which can't be avoided till all motors runs in a future cooled with the kyrpto geen stuff used on non water sports motors.

The white stuff found on the thermostat accounts for that, inspect with flashlight the thermostat's internal housing, it it same or worse than the thermo cond found ?

Asside from cooling issues, the motor may already have developed other mechanical or electrical issues that will need to be correctly troubleshooted if wanting that motor to spring back to life running strong specially at wot.

Happy Boating​

I can’t tell where the white smoke is coming from. But not for lack of trying, it just seems to form around the engine. My best guess is from the exhaust above the waterline. And yes, the pee stream is strong, as it should be.

I don’t understand what you mean by “thermo cond found”. The thermostat works fine, or it did a year and a half ago when I got the motor ( I checked it). Also, I ran some descaler through the motor last year. Some crud came out, but it wasn’t a whole lot.

I checked all the electrical timing stuff when I got the motor, but I suppose something could have happened between now and then.

 

[Sea Rider]

I can’t tell where the white smoke is coming from. But not for lack of trying, it just seems to form around the engine. My best guess is from the exhaust above the waterline. And yes, the pee stream is strong, as it should be. I ran some descaler through the motor last year. Some crud came out, but it wasn’t a whole lot.

With a descaled motor all water passages are way cleaner than before and motor peeing strong. The white/blue smoke seen above the waterline appears when at neutral, idle ? aside the smoke, does the motor runs strong thru the whole throttle range ? The motor being an oiling injection model and now running constant 50:1 fuel/oil mix at lower rpm will account for seeing more smoke around that area. Why is the motor running with morefuel/oil ratio than 50:1 ? More oil, more smoke at reduced rpm.

Happy Boating​

 

[3ric]

With a descaled motor all water passages are way cleaner than before and motor peeing strong. The white/blue smoke seen above the waterline appears when at neutral, idle ? aside the smoke, does the motor runs strong thru the whole throttle range ? The motor being an oiling injection model and now running constant 50:1 fuel/oil mix at lower rpm will account for seeing more smoke around that area. Why is the motor running with morefuel/oil ratio than 50:1 ? More oil, more smoke at reduced rpm.

Happy Boating​

The white smoke is barely apparent at idle, but is abundant at any bit of throttle. And no it doesn’t run through the throttle range. About 2 outings ago, it would try to die in reverse unless I could get it past the lower part of the throttle range. And it would die at idle occasionally, otherwise it ran fine in the upper range. But the last time I took it out, was when I started noticing the white smoke and quite a bit of it. At the time I attributing to the oil injection lines draining into the crankcase (not recognizing the difference between white and blue smoke at the time) and the extra oil just burning off. But it continued to smoke and steam a little for the rest of that trip. But I could still get it up to full throttle, I just didn’t much and made it a short trip. I took it home and put it in a trash can and it idled very rough and when I would put it in gear and give it a little throttle it would die. Note: it wouldn’t produce a lot of white smoke at idle, but when I put it in gear it would. And then after it would die I would not be able to get it to even idle for at least 24 hrs.
I took it to a mechanic for a diagnostic. He was not supposed to do any repairs but cleaned and put kits in the carbs ( that I had told him I cleaned myself and kitted about 6 months prior, and I feel confident I know what I’m doing). He said it was a fuel delivery issue and also replaced the fuel pump (unauthorized ). The mechanic and I parted ways and the motor runs exactly as it did before. So, very clean carbs, and a new fuel pump.

I also replaced all the fuel lines etc. last year. I am neurotic about fuel quality (no alcohol, I even clear the hose at the pump before filling gas cans etc., and I double check for water in the fuel tank. I did not observe any. I am running 50:1, and the amount of blue smoke, in my opinion is appropriate for premix, especially for as rough as it idles. New plugs also, with the gaps checked. Sorry for the novel, but maybe the devil is in the details?

 

[99yam40]

seems you said it died and produced white smoke.
"But when I put it into gear or accelerate, it will die and produce lots of white smoke."
now you say it produces white smoke at idle and and then dies
which is it?

And I have a hard time believing you cannot see where the white smoke is coming from on the motor