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I Have a craftsman garden tractor with a 16 hp twin briggs engine...if I increase throttle rapidly...I get a big puff of smoke...not black smoke..but maybe bluish or gray...what would cause this?..the engine does not smoke any other time...only when throttle position is changed...is this the first sign of ring problems?..or carb?..
 

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I Have a craftsman garden tractor with a 16 hp twin briggs engine...if I increase throttle rapidly...I get a big puff of smoke...not black smoke..but maybe bluish or gray...what would cause this?..the engine does not smoke any other time...only when throttle position is changed...is this the first sign of ring problems?..or carb?..

mine is doing the same thing, i think its the rings.
 

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Discussion Starter · #4 ·
not what i wanted to hear willtractors!.....but what I do not understand...is if its the rings..why does it not smoke all the time?...
 

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i THINK becaus when you throttle up, it stirs up the oil more, so it seeps through the rings easier. i could be wrong though
 

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It is burning oil all the time, you just can't see it. You can, however, smell it. The reason it smokes under load is that oil will accumulcate on top of the piston, and when the engine is loaded, more heat is available to burn the oil, as the flame becomes larger.
 

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If it's gray smoke, it could be running a bit rich, adjusting the carb is cheap ... I'd go by the book on getting the carb settings correct before I'd worry about rings.

A compression test might give you some indications as well.
Test the compression of each cylinder after it's been sitting for a while ...

... then squirt some oil into each cylinder (try to coat the cylinder walls where they meet the piston ... fairly even all around)
then check the compression again, each cylinder.

If there's a large difference in the readings, rings need replacing. (Reason being the oil will make a good seal and give you a higher reading than rings alone ... if the rings are shot.
Not such a difference if the rings are good)
Note: It will definitely smoke after this test, of course ... but only for a minute or so.

Hope this helps, :thThumbsU

Dave
 

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Can the rings be replaced by removing the head or do the pistons have to be removed?

Thanks
The pistons have to be removed from the cylinders.

Frankly, I wouldn't worry about a puff or two of smoke. Monitor the oil consumption over time, that will tell you about the engine's condition. A puff or two of smoke will do no harm, and is not worth pursuing, IMO.
 

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The pistons have to be removed from the cylinders.

Frankly, I wouldn't worry about a puff or two of smoke. Monitor the oil consumption over time, that will tell you about the engine's condition. A puff or two of smoke will do no harm, and is not worth pursuing, IMO.
:ditto::ditto: my tiller smokes real bad, all the time. runs great so it can smoke away:drunkie:
 

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I'm using about 1/3 quart/2hrs of mowing, would like to look into doing the rings and maybe valve seals as I get a good 20 sec of smoke at start after sitting for a week.
Is this very difficult – any step by step instruction – special tools? I’m pretty handy with such things but never done this before.
Thanks
 

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not very many special tools, just a ring compressor, torque wrench in inch pounds and you mind. Big thing is being careful not to scratch things and it must be kept very clean.

It's pretty simple otherwise. there's videos on YouTube and books on how to work on them.

your best resource is some one who has done it before because they ca instruct you by the situation and a book can only give you a basic over view of it, nothing too in depth.


Hope this helps!
 

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also, you'll need one of those three finger honing tool to work up the cylinder walls before they meet up with the new rings... The walls needs to be smooth, flat, and cross hatched (by moving the tool in and out continuously while it spins) so as to make a best possible seal to the rings. Otherwise, if this is not done, the rings will NOT seal properly to the cylinders.
 

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not very many special tools, just a ring compressor, torque wrench in inch pounds and you mind. Big thing is being careful not to scratch things and it must be kept very clean.

It's pretty simple otherwise. there's videos on YouTube and books on how to work on them.

your best resource is some one who has done it before because they ca instruct you by the situation and a book can only give you a basic over view of it, nothing too in depth.


Hope this helps!
In the past when I was money poor I used some large hose clamps to compress the rings (not tight on the piston!) for installation and it worked fine.. As far as the ring grooves go you can use one of the old ring's enpieces to carefully remove the soot and grime from the guides. Patience and diligence is all you need..
 

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Most of my small engines will belch out a puff of bluish or black smoke from the exhaust when the govenor kicks in under a heavy load...I consider it normal unless it consumes a lot of oil in a short time ..the puff is most likely caused by the increased compression when the engine is put "to work" and the throttle is opened..an engine idling mightonly have 35 lbs of compression,when the throttle is opened and allows more air in to be compressed,the compression pressure increases dramatically,and will force any oil in the cylinder that collected from loose valve guides or worn rings to be combusted and blown out the exhaust..

If the engine does not have uch blowby smoke coming out of the breather tube from the valve cover,chances are the rings aren't that bad,its probably the valve guides or stems being worn that lets oil get inhaled into the cylinder..but remember,if you just tighten up the valves by replaing them with oversized stems,chances are excellent the rings will allow more oil to pass than ever--the engine parts all wear together and replacing half of them increases the load on the rest of the worn parts,that may not have appeared worn until you find it starts smoking when it never did before..
 

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Most of my small engines will belch out a puff of bluish or black smoke from the exhaust when the govenor kicks in under a heavy load...I consider it normal unless it consumes a lot of oil in a short time ..the puff is most likely caused by the increased compression when the engine is put "to work" and the throttle is opened..an engine idling mightonly have 35 lbs of compression,when the throttle is opened and allows more air in to be compressed,the compression pressure increases dramatically,and will force any oil in the cylinder that collected from loose valve guides or worn rings to be combusted and blown out the exhaust..

If the engine does not have uch blowby smoke coming out of the breather tube from the valve cover,chances are the rings aren't that bad,its probably the valve guides or stems being worn that lets oil get inhaled into the cylinder..but remember,if you just tighten up the valves by replaing them with oversized stems,chances are excellent the rings will allow more oil to pass than ever--the engine parts all wear together and replacing half of them increases the load on the rest of the worn parts,that may not have appeared worn until you find it starts smoking when it never did before..

I do not have oil coming out of the breather - would you recommend taking the heads off and do whatever I can to rebuild the valve system and see how much difference that makes?
Looks like this can be done without removing the engine.
 

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Like I said before,in 90% of the engines Idid just a "valve job" on,the rings and or piston wear became very apparent right away--as in smoking constantly instead of just a puff when the throttle was opened...I'd run it as is,maybe add a bit of Lucal or Marvel oil treatment to thicken up the oil a bit--..if your going to open up the engine,you might as well go all the way and do a full rebuild..it's not that much more work once your into it..
 
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