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Rick, Factory Authorized Trainer
Category: Small Engine
Satisfied Customers: 8057
Experience:  Outdoor Power Equipment technical trainer since 1990, covering eight states.
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I have a B&S engine model number 287707, type number 1255-E1

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I have a B&S engine model number 287707, type number 1255-E1 on a Craftsman Lawn Tractor model #NNN-NN-NNNN I seem to have 2 interrelated problems -- starter drag and starting white smoke. With a fully charged battery, the starter will turn the engine over for only one compression cycle with each starting attempt but after several minutes and multiple tries, it will finally spin the engine over enough for it to start. (This only happens when the engine is cold. Once the engine is at operating temperature, it spins and starts just fine.) Then, immediately after starting the cold engine and for a very short time, bellowing white smoke will come out of the exhaust. However, once the engine is running "normally", it does not smoke at all, is not using excessive oil, and has good power. This whlte smoke does not occur if I start the enging after it has warmed up. I've had the mower for about 10 years, the starter is the original and the carb has never been rebuilt. Any clues as to where to / how to trouble shoot and fix the problem will be greatly appreciated. Thank you.

MM Marosko
Coupland, Texas
Let's do some troubelshooting. Does the engine oil in the sump smell like gas?
Customer: replied 6 years ago.

Thanks for your reply. I'll have to go check and get back to you. It will be tonight, TX time, before I can reply.


Hi Max,


Just let me know when you can and we'll continue.

Customer: replied 6 years ago.

Yes, the oil as the aroma of a 2 cycle fuel/oil mix.

Customer: replied 6 years ago.
Rick, Since I surmised part of my problem is in the carburator and not the internal engine, I tried to start the engine this morning. It was out of gas so I put about a 1/2 gal of fresh fuel into the fuel tank and cranked the engine. The starter is still "dragging" and has difficulty spinning the engine through a full compression cycle and when it did, a lot of fuel came out of the exhaust pipe but the engine would not start so, not wanting to burn up the starter, I discontinued my efforts waiting until I hear more from you. Thanks, Max

Hi Max,


If you are getting gas in the sump, the usual cause is a bad needle and seat in the carburetor. Replace those items and check the float as well. If you shake the float and hear liquid inside, the float is bad and will need to be changed. Otherwise, just the needle and seat.


Check the air filter. If there's oil contamination, change the air filter and clean the air filter box and breather as well as you can. Change the oil and oil filter is equipped and you should be back in good shape. This type of problem rarely causes any engine damage.


Hope this helps! Keep me posted. Let me know if the starter dragging doesn't go away. I suspect it's because the sump is overfilled.

Edited by Rick on 8/3/2010 at 7:38 PM EST
Customer: replied 6 years ago.
Rick, thanks for your analysis. The owner's manual schematic of the engine lists a part number 498030, needle value, but nothing for a "seat" plus the schematic of the carburetor does not show the location of that part number. It shows a carburetor nozzle (part # XXXXX) that inserts into bottom of the carburetor but I don't believe that is the article you are talking about. Can you give me some guidance as to where I'll find that potentially bad needle value and seat and how do I get to it? The dip stick is showing between full and add oil and the starter still drags but as you suspect it may be because of the excess fluid in the cyclinder, the starter doesn't have the power to spin the engine thru the full compression cycle. Do you recommend removing the starter and taking it to a shop for them to ckeck out? Appreciate your help. Looking forward to your reply.Max
Some of the carbs don't have a replaceable seat, just a needle. Let me verify on yours and I'll let you know in a few minutes, please.

Here's the parts you will need on your engine.




Customer: replied 6 years ago.
Rick, thanks. You've been a great help and I really appreciate it. Before I "sign off', any comment on the starter continuing to drag with the sump NOT overfull"? Also, owner's manual says that part 106 (part #231854, inlet valve seat) "requires special tool to install". Can you tell me what kind of "special tool" is needed and would I be advised to just buy a complete carburetor overhaul kit and do the entire carb while I'm at it? Thanks again, Max

Without inspecting the carburetor I cannot tell you for sure, but I will say that with today's gas carburetor repairs are the number one thing we see by far, so based on the odds rather than specifics I would clean and rebuild while I was there as a good insurance policy. I'd also recommend a can of Sea Foam (available at Walmart) mixed with the gas according to label directions. It will help stabilize the fuel and clean the fuel system. It's a great product, and no my brother-in-law doesn't work for them. Laughing


As for the starter dragging, try it with the spark plug removed. It it spins over properly then compression is the culprit. (Otherwise a starter problem - battery, cables, starter, etc.) While it may be a faulty compression release, most often a valve adjustment does the trick. That's where my money is based on the odds, so let's try a valve adjustment first.

Intake - .003"/.005"
Exhaust - .005"/.007"

The setting should be done on a cold engine with the piston 1/4" past top dead center on the compression stroke.

Here's some additional information that shows the process in detail. Scroll down to the bottom of the page to where it talks about adjustments. It will link to some helpful pictures as well. If there's anything you're not clear on, please let me know.

Valve Info

Hope this is helpful! Let me know...



Betcha thought I forgot, huh? Here's the procedure and the part numbers for the tools on the seat. A smart fellow like you can probably improvise the removal now that you see how its done. We've always use a self-tapping 1/4-20 hex-head screw. The installation tool is listed below as well. If you have a friendly local shop they might even be willing to loan you one.





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Customer: replied 6 years ago.
Thanks for the help Rick. Pleasure working with you. Now if I can just get my mower to work all will be well. Thanks again, Max
You are so much more than welcome. And the pleasure is mine. Thank you for the accept, and best of success in all your hands touch.

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