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JoggerFogger

Lots of smoke. Where should I start? w/ video!

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JoggerFogger

This thing has always smoked. Even 25 years ago when it was always working. I think it's time to put a stop to it.

12 years ago under the guise of my boss (who built drag motors as a hobby) I took apart this motor and he declared the rings, valves, bore, etc. to be all in fine condition. It smoked then too.

I'm just wondering if there's a common problem, hack, adjustment, trick, cause, fix that keeps the smoke down.

Granted, this motor has spent the better part of the last 20yrs sleeping, and after it's running the smoke dies down. Until a load is put on the motor, or if it's throttled up quickly.

Any ideas on where to start?

-Kevin

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Tonyvdb

I don't know a lot about the B&S engines, but the first thing I would do is make sure you're not over filling it with oil. There are lots of discussion here about what type of oil to use, try searching here, its good reading if noting else. Could be a broken ring, or the oil breather stuck open letting it suck oil into the carb.

There are lots of folks here that have a wealth of knowledge about these engines.

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JoggerFogger

Breather? :I

That must be the little pod on the farmer's right? With a hose going to nowhere?

Is the breather some sort of one way check valve? Where is the hose supposed to go?

I think this is the right direction.

Thanks, Kevin

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JoggerFogger

Hummm. Well mine just goes to the atmosphere. I could see how that would cause smoke if it was pushing oil mist back into the carb. I don't think that's my problem.

When I pulled this motor apart 11 years ago the rings were fine (they could be broken now, but it smoked with good rings back then too). Is there a easy way to check the valve guides? And when I mean easy, like the shade tree mechanic style inspection/fix?

I saw a video by Zippo talking about using transmission fluid for sticky valves... but I'm guessing they're not stuck, but rather loose and not making a good seal? If I open the plate where the valve springs are, will I see a bunch of oil in there if the valve guides are bad?

I would rather avoid taking this motor to a machinist to be fixed, especially if there's something I can do on my own. :)

Thanks in advance again!

-Kevin

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RayS

You say the rings were fine 11 years ago. I assume the bore was checked to see if it was within specs.

Is that breather that goes to atomsphere plugged up? They have wire mess in them if I remember correctly. They can be removed and cleaned out with brake cleaner.

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JoggerFogger
Originally posted by RayS

You say the rings were fine 11 years ago. I assume the bore was checked to see if it was within specs.

id="quote">I have no idea, but I'll be inspecting it when I get home first thing. I have brake cleaner and I'm not afraid to use it.-Kevin

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RayS

I would flush the breather out with brake cleaner first. That is the cheapest route. It sounds like it has been sitting most of it`s life instead of running. Those breathers on the front of the engine can plug up. Oil can harden over time in that mesh. It is worth a try. I would do the carb adjustments as well. If you need a copy of the Briggs Vintage Repair Manual send your email address in a private message and I will gladly send it to you. It has all the spec. for that motor as well as many others.

That noise could be the flywheel rubbing the shroud too.

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JoggerFogger
quote:Originally posted by Multiplicity

....That engine has some excessive mechanical noise within it....Not sure carb is adjusted right, unless just coming off chokeat startup.....Too rich.....


id="quote">
id="quote">When I had the motor on the bench I noticed that several of the shroud attachment bolts were missing. When I replaced them, I had to do a little massaging to get the holes to line up, and I think the should is in fact rubbing the flywheel. The carb was not adjusted right at all. This was the first cold, cold start after 11 years and I just rebuilt the carb with no idea on what the baseline settings were for the mixture screws. I think I did 1.5 turns out on both. And yes, it was on full choke. I was amazed that it even started! I had my iphone rolling just to capture the explosion if it happened.If the vent was totally plugged, I assume it would be building crankcase pressure? And pushing oil up where it's not supposed to go?I also think I have the oil filled too high. How much oil should it hold from totally empty to full? Not ever having a manual (until now) my dad and I always filled it up right to the brim. Sounds like that's too full! yeehaw.-Kevin

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HubbardRA

Without a dipstick, you should only fill to bottom of the threads in the oil check.

Briggs sells a tube that screws into the hole where the plug is, and a dipstick that screws onto the tube. I bought one a couple years ago for a 12 Hp.

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HubbardRA

If the problem is not the breather or the carb, then I would suggest that you install new rings on the piston.

It sounds like you may have a set of chrome rings sitting in a shiny glazed bore. In many cases the hard rings will not seat into the hard glaze. I have seen this happen on B/S engines and also on automobile engines.

If I were you I would get a new set of rings and "do not" get the chrome ones. Then I would either hone the cylinder or just use some coarse sandpaper to break up the glaze on the cylinder. With the new rings and a roughened cylinder, you should get good seating and have good compression and very little blow-by on the oil ring.

I know there are those who will totally disagree with what I have just said, but chrome rings do not always seat well in all cases. It has happened to me a couple times, and this solution worked well.

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rokon2813
quote:Originally posted by HubbardRA

Without a dipstick, you should only fill to bottom of the threads in the oil check.Briggs sells a tube that screws into the hole where the plug is, and a dipstick that screws onto the tube. I bought one a couple years ago for a 12 Hp.


id="quote">
id="quote">I concur with Rod. Make sure the oil level is not too high. When we were pulling, one of the kids put about 1/2 pint too much oil in his engine. It smoked bad enough the officials DQ'd him and would not let him pull.10 minutes later he pulled. Everyone was trying to figure out how I replaced rings in 10 minutes. :o:O

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MysTiK

Tweaking the carb screw adjustments will clean up light smoke caused by too rich a setting - it worked for me. It's not clear if you did that, not clear if eng was running on heavy choke either.

OTOH in the video it looked more like white smoke - but then you said it cleared up except when quickly throttling. I'm confused by those statements - but if you know what happened, that's the main thing.

Also, engine has been sleeping for decades. Have you run it for more than a few minutes. I can imagine everything drying out over the years - and then the oil overfilled - that will smoke it.

I agree w getting the breather sorted.

So I think getting these little details right would be a good thing. I'd give it half a chance before tearing it down. I tend to think there's not much wrong with it, except these little tweaks. But I have lost track of what was done, or not done, already.

just my 14 cents worth. Nice to know it's alive.

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JoggerFogger

Yea, sorry if the details are a little confusing.

A. Has been rebuilt at least 20yrs ago, but with little run time since rebuild. Unknown quality of build and if the valve guides were attented to.

B. I don't know if it's blue smoke (oil?) or white smoke (rich?). I thought black would be too rich?

C. In video, choke was on for 3 seconds.

D. I believe it's overfilled. I filled it until I couldn't put in any more- about 1 and 3/4 quarts.

E. Verified the breather works and is clear last night.

So if it is indeed oil that's burning, there's only two ways it can get in the combustion chamber:

1. by the piston

2. by the valves

(3. through the breather if it were correctly hooked up to the carb.)

I've ruled out the breather as a problem. I think I'm going to work in this order:

1. Lower the oil level, and tune the carb correctly.

2. If that doesn't do it, install new rings and hone/sand cylinder.

3. If it still smokes, just live with it, and watch the oil level.

So I've been working on motorcycle carbs for the last 10-12 years, and If they're off just a little, it just won't run at all. I'm kind of amazed at how far off the settings can be and the motor still runs.

I did spin the motor a fair amount while I was trouble-shooting the lack of spark. During that time I'm sure some amount of oil got splashed around inside the motor, but not sure how much. I didn't have the fuel hooked up yet at that point. I'm really hoping that some simple tweaks solve this problem, and I don't need new valve guides.

Regardless, I'm going to buy a farmall or similar stacked muffler and maybe that will just shoot the smoke straight up. :D

-Kevin

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MysTiK

My own was a smoker when I got it. It had HORRIBLE oil. Multiple changes to clean that out.

Mine tended to smoke if idling a short while, then hit the throttle.

Eventually I tweaked carb settings, (carb has wear) and was able to further reduce smoke - net change leaning the carb setts.

Mine runs clear, but it is still vulnerable to smoke if it idles - but far less than it was originally. So I can live with that.

Thank you for the summary. My point is merely to do the simple little tweaks, get best you can that way, and then consider more.

So breather, oil level, carb settings first. Also a new stack sounds good - old muff could be oiled also.

Then you have a level playing field. Also I think a little run time to kinda break it in after it's long sleep. That's how I try to baby it. I like to assume things are good until proven otherwise. And I heard you say it burned less smoke after initial startup - so how much less can that become? I also tend to avoid engine work; largely due to lack of experince and tools. My olde engine runs fine; but it is not perfect by any means. I am willing to make do; and my problems are not excessive for day to day ops. Others have their own standards, high or low - it's cost, labour, personal standards, etc. - and it's your tractor, your call, your work, etc.

Thx again for summary of the situation. It sharpens the focus. And my discussion might be dulling the scalpel. Multiple points of view are possible. There are other items on the agenda as well.

I do hope this brief discussion helps further progress rather than impedes. Such decisions must needs be made; but there are no absolutes.

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Architectdave

FWIW I had a B10 that when I bought it started and ran fine, got it home discovered it was very low on oil, topped it off and it smoked like a son of a gun. Obviously the PO ran it that way so it wouldnt smoke and he could sell it. My guess is piston rings.

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