engine smokes

[rwebb]

I have a 50 year old Murray riding mower with a briggs and stratton engine model 289707 type 0121 01. It smokes badly (white smoke). I believe there is gas in the oil. I'm going to break the engine down. What should I look for? I've owned the mower for about 5 years, and it's been great until now. Thanks

 

[CraftsmanGT]

No reason to tear the engine down. First thing is smell the oil on dipstick. IF it smells like gas change the oil right away. Install a fuel shut off valve and use it everytime your done using it and run it out of gas, or clean the carb and check the needle and seat. Replace if needed.

 

[Rivets]

As stated check for fuel in the oil by pulling the dipstick and look for two things. Is it over the full mark and does it smell like gas. If the answer to both of these is no, then you will have to do a few more checks. If it is overfull and smells like gas, your problem is the carb which will need a good cleaning plus rebuilding. Adding a fuel shut off valve is putting a bandaid on the problem and not fixing it. If you have to rebuild thecarb, here is a procedure which I use.

Needle and seat replacement

Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.

I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.

With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. *Next check to make sure that the float does not have any liquid in it. *If it does, replace. *If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.

PS: *On the side of some Tecumseh carbs you will find a plastic cover. *Under this cover will be an idle jet. *Remove it and check to see that the jet is open both horizontally and vertically. *You should be able to push the old float needle wire through the vertical opening.

 

[royrodgers]

As stated check for fuel in the oil by pulling the dipstick and look for two things. Is it over the full mark and does it smell like gas. If the answer to both of these is no, then you will have to do a few more checks. If it is overfull and smells like gas, your problem is the carb which will need a good cleaning plus rebuilding. Adding a fuel shut off valve is putting a bandaid on the problem and not fixing it. If you have to rebuild thecarb, here is a procedure which I use.

Needle and seat replacement

Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.

I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.

With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. *Next check to make sure that the float does not have any liquid in it. *If it does, replace. *If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.

PS: *On the side of some Tecumseh carbs you will find a plastic cover. *Under this cover will be an idle jet. *Remove it and check to see that the jet is open both horizontally and vertically. *You should be able to push the old float needle wire through the vertical opening.

Dear Rivets,

Those are, without a doubt, the best and most clear and understandable instructions that could have been posted. I have had this same problem and I think even I could have followed your instructions. You surely must have been an outstanding teacher when you taught.

 

[reynoldston]

I have a 50 year old Murray riding mower with a briggs and stratton engine model 289707 type 0121 01. It smokes badly (white smoke). I believe there is gas in the oil. I'm going to break the engine down. What should I look for? I've owned the mower for about 5 years, and it's been great until now. Thanks

50 year old mower. Sound like more then a carburetor problem with gas in the oil. Just could be its just worn out. You are going to find its going to be hard to even find parts for a mower this old. When you rebuild the engine make sure you check the cylinder walls for wear and for loose valve guides. The cost of machine work to rebuild something this old can be costly and unless its something you want to save you might start thinking its new mower time.

 

[Rivets]

Reynoldston, I agree with you that rebuilding the engine may not be the best option. That is why I asked about the oil level and smell. If it has fuel in it, rebuilding the carb may be the most cost effective option for the OP. Unless the OP has a real love attachment to this engine, I would not recommend rebuilding a 50 year old Briggs.

 

[mechanic mark]

Results operators manual & parts list

http://evanosaurus.com/ebooks/270962 Single Cylinder L-Head BRIGGS & STRATTON.pdf engine repair manual

Amazon.com : Briggs & Stratton 699831 Carburetor Replacement for Model 694941 : Lawn And Garden Tool Replacement Parts : Patio, Lawn & Garden Nikki carb.

Amazon.com : Briggs & Stratton 698171 Carburetor Replacement for Model 697594 : Lawn And Garden Tool Replacement Parts : Patio, Lawn & Garden Walbro carb.

These are examples for new carburetor price depending on manufacturer, also Walbro has gravity as well as pump feed with different part numbers listed in parts manual.

 

[motoman]

We need a "sticky" thread like other forums for classic shop procedures beneficial to all. Then instead of asking over and over a searcher can see the information up front. Whaddya think?

 

[bertsmobile1]

We need a "sticky" thread like other forums for classic shop procedures beneficial to all. Then instead of asking over and over a searcher can see the information up front. Whaddya think?

Good idea except no one will read it because it is not THEIR individual problem because it is about a Briggs & they have a Kohler.
What do we post here that is not in the trouble shooting guide that comes with every mower and is available for every mower on the net free.