My Tractor Forum banner

Briggs 16hp single- intermittent smoke

3767 Views 18 Replies 6 Participants Last post by  Richard-tx
I started up my used 16hp single Briggs engine on my 8162 yesterday. It smoked a touch on start up and ran OK. After about 2 minutes at WOT it started belching out gobs of blue smoke and had a loss of power. It was most impressive the amount of smoke it produced. It was like the Blitz Fogger on my father's SC.

I decided to let it run and then it stopped smoking after a minute and ran just fine. I started it again today and it did the same thing. I am thinking the problem is a cracked piston. Once it thoroughly heats up, the crack closes and it stops burning oil. Does that seem reasonable?

Maybe something with the crankcase ventilation system?

Is there anything else it could be?

See less See more
1 - 19 of 19 Posts
Too high an oil level in the crankcase. Or oil in the fuel pump from a bad pump.
Pulse type pump on this one Don. I suppose it could still be the pump but I think that is a stretch.

I am thinking that the issue is the crankcase ventilation system. Oil is getting thrown up when cold and it is getting dumped into the carb. I will disconnect it tomorrow and try again.
Worn cylinder and high oil level. I can set my watch by my 816S doing the same thing. If I top the oil to Full and then crank and warm up for about 3-4 minutes at mid throttle and then go to mowing.. it will do it almost every time. 30-45 seconds and it clears up, eats the oil, and we keep going. I have a new block for mine just haven't gotten around to building it yet. Pull the air filter and you'll more than likely see the oil in there. It is pushing it through the breather by the valves, into the intake, and eating it. The thing about it is, as worn as the cylinder is in my block, it still makes good power. It is no spring chicken, but it pulls the 50" deck...
See less See more
Nature of the beast. I figured as much. Thanks Jimmy.
For what it is worth.. I have put probably 70 hours on this motor (hard hours) and not really experienced much issue other than killing air filters. I buy them for ~$4.00 though so I don't worry. The tractor still runs and moves so it's not an issue and I have never experienced a "No Start" situation. One thing that helped slow it down was a new set of points set correctly which ultimately affects the timing. Making sure they were gapped correctly helped a bit.
See less See more
I will likely do something with the crankcase ventilation since it seems is the source of the issue. I will verify that later today.

I have to put a new needle and seat and gasket in the carb anyway so that means I will have to disassemble it. Those updraft carbs can be a pain to work on but the crankcase never fills with gas if the needle doesn't seat.

I am on the hunt for a replacement engine. I would love to pick up a CCKA or B48 for it.
See less See more
I love my Onans but the both of the Briggs have been solid performers for both dad and me. If you pull the crankcase breather out of the carb, be sure to seal the breather well. You could put an angle cut on a piece of tubing and install it into the header pipe and hook the crank case breather to it. That would pull a vacuum on the crank case and probably eliminate any chance of pressure if you want to get that carried away. I just let it push oil til it's happy and note that spot on the dipstick. Then I never fill above that and don't worry. I also run full synthetic in it too so 3oz low isn't the worst thing in the world.
See less See more
That's an easy engine to re-ring, you can do it in situ. I don't think you'll find any problem with the breather. It probably has too much blowby when cold.
Definitely a blow by issue. I will have to tear it down and fix it. It seems like a reasonable engine. Odd that it will smoke as bad as it does for a short period of time and then stops.
My b/s on my sears did the samething,but ran ok.I replaced the rings and now runs great. Just to much blowby.
I haven't pulled mine down fully just the head off and I have measured .024" taper from top of bore to top of piston at BDC. I doubt rings will fix it. I need a sleeve, piston, rings. Hopefully yours isn't that bad Richard but I seriously doubt it is much better. These engines run well terribly worn out and when you get smoke, etc it is about over.
See less See more
Is it a Briggs overhead valve? They are well known for head gaskets remove air filter and inspect. What happens is the gaskets goes pressuring crank sending oil up breather tube into carb then into intake. Plugs will have oil on them it will get worse under a load driving pto on.
If its worn rings a few drops of oil in plug hole will raise compression on tester gaskets not so.
It is not an OHV engine. It is a single cylinder flat head. I will be looking at it later this week. 2 days of rain are moving in so that brings everything that is to be done outside the shop to a halt temporarily.

I am likely looking at a major overhaul. I likely won't do it. I am thinking of just selling the engine on CL or scrapping it. I would rather spend the money overhauling a Onan twin. I believe I get more bang for the buck. The trick is to find a suitable Onan twin. I really need to find two of them.
See less See more
You need an Onan single to go with all your Onans. Would kind of round out the fleet!
I am going to stick with the Onan twin engines. They are smoother. I would use 4 cylinder engines if someone made one that was the right size and was air cooled.
Do you mean like this? Unfortunately, it has no provision for an electric starter and I don't know what the crankshaft looks like, but it would be an interesting conversion.


See less See more
Yup...that would be cool. I would figure out something for an electric start. It would turn a couple of heads at the next mow-in.
1 - 19 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.