Engine not running right

[BradB]

Just this last week I first started my B-10 after two months of work and it runs very good except for a miss here and there. The carburator is set to where it runs best yet it still misses. Not really a serious miss but it puffs a little black smoke? I can't adjust any leaner of a mixture. Is it just because the motor is new? Or is there something wrong with the carb? The only thing I can think of is the black hose from the air cleaner to the side of the block (which is torn and I ordered a new one). Any hint? Thank you! BradB

[JMorin]

Dear Brad, Is your fuel fresh/clean/free of water? Just a thought. Jim

[Woodydel]

Black smoke is rich mixture. If carb is dirty inside it may not adjust properly...Woody

[John_RI]

Brad: I haven't been inside of of these carbs yet, but since it's got a float, I'm assuming it's got a "tang," on the bracket holding the float. The tang is the piece that pushes against the backside of the float valve, that you can bend to adjust the level of the float. By this I mean, it operates like the "ball" float in a toilet, in that you adjust how high the liquid rises before the supply is shut off, by adjusting the float height. Except in a toilet you bend the rod—in the carb, you bend the “tang” at the end of the “rod” or float bracket. (Note: Depending on configuration, the direction you need to bend the tang may be opposite that in a toilet, as the carb's float valve is over the float, not under it, like in a toilet.) Anyhoo, if the float is set such that it's letting the fuel rise too high in the float bowl before it actuates the needle vavle to shut the fuel flow off, it can cause a rich condition (your black smoke) by overwhelming the float valve. Normally you bend the "tang" which pushes against the backside of the needle valve, whichever direction you need to to close the valve "earlier," i.e., with the fuel a lower level. Try doing this so the fuel is at a slighly lower level when the valve shuts, than it was before, and see how you do. Does the skip/black smoke coincide w/ you hitting a bump or tipping the tractor? That would be consistent w/ this condition, IMHO. A related possibility: The float valve's "needle" and seat can both become worn. There should be no INDENTED ring on the point of the needle valve, where it contacts the seat. If there's a "scum ring," but the surface is not worn, it should be okay. Keep in mind the "seat" the needle rests on can also become worn. Too much space, due to wear, in this area, or ridges, could let extra fuel through, giving you an intermittent rich condition, particularly if the valve is hanging up on the edge of any ridge or wear pattern. Replacement of the needle (and, ideally, the seat) are the fix in that case. I'd like to know what the needle looks like, if you check. GENERALLY, i.e., I haven't worked on the tractor carbs before, you access it by dropping the floatbowl, removing the pin which hinges the float, carefully removing the float and dropping the small, dead-grass-colored brass float valve into the high grass (b/c tractor doesn't run) under the tractor. Then you can take a wrench or socket to remove the seat itself, to show the parts man/woman, so they can find a replacement for the valve you lost. Speaking of lost, there may be a hair-thin spring holding the valve to the tang. NOTE IT’S POSITION, prior to disassembly. It needs to go back the same way. NOTE: Don't bend the tang before you check the valve face and seat, as it's more likely the valve is worn than that the float got bent. Also, shake the float--any sloshing you hear is telling you you must get a new (nonleaking) float. Please note, I am certainly not a "professional." Hopefully others will correct me if I have steered you wrong. Good luck, my man. I hope this helps, as it is the product of a lifetime of experience, a concept I'm put in mind of by the fact that today is my 41st. birthday. :) Peter

[Al]

Hi, On this carb, remove the adjustable high speed jet assembly and use a Jet wrench or a screwdriver that is straight sided and hollow ground and remove the the jet/nozzle that is behind it before you try to take the float bowl off the top half of the carb or you will bend or break the part of the nozzle that goes up in the venturi in the upper half. Then it will be necessary to replace the nozzle. There are several numbers for them and they are not interchangeable. If you try to take the nozzle out with a regular screw driver the blade will be tapered and will damage the threads when you are trying to break the nozzle loose. If the screw driver fits in the hole, the blade will be too narrow to contact the outside edges of the nozzle and since the center is counterbored will chew up the slots and spread the brass so the nozzle won't come out and it messes the threads up. We have fixed a number of these carbs after being damaged and had to scrap a lot more. These threads are an odd size and the taps are only available from Briggs. If you use a screw driver select one that is as wide as the hole at the tip and grind the sides off until the blade is round and straight. Then take the tip and grind a little out of the flat on the face of the wheel so it is hollow ground and the flats are paralell instead of tapered. This how the Briggs jet wrenches are made. If this carb hasn't been apart for s while you have a very good chance of having scrap if you don't do this. Good luck, Al Eden

[BradB]

Well Happy Birthday Peter! And to everyone, thank you for the help. I'll try and do a little adjusting and will check back here with reports of any success or failures.

[Ryan]

I would not work the tractor without the pc hose hooked up. You wouldn't want a fresh engine hurt by sucking in dirt. I have seen alot of engines ruined because of this. If you were running the engine like this, you more than likely have a very dirty carb now. Ryan

[BradW]

Hi Brad from another Brad :) if you just rebuilt your motor, you should rebuild the carb too. That would be great with the fresh motor. Hope your B-10 turns out great, I have an early B-10 and really need to paint it and put a motor in it!,-BradW