Out of patience,

R

red423

Member
Here is where I am. 2015 TB 42 rider with 15.5 hp briggs low emissions engine, catch the low emissions part, I have tried three count em three, different carbs off amaz and flea bay, it has the electric shut off and not one will keep the engine running for a constant operation, I have tried to look up jetting and only get part numbers, that don't really help. I then went to a sears pts catalog found that the Nikki carb is specific to this model and just ordered another one yesterday. I am at my wits end, I found the coil s/o wire grounding out fixed that then adjusted the valve lash thinking burnt walves or bad seats, got it to run 3/4 throttle then is started dieing out then stalled, started and wouldn't barely run. new plug, will install new coil with next new carb, is this model so tempermental on jetting??? the generic carbs state 15 to 17 hp when listed, yet all common sense tells me that no, need specific jetting for a low emission 15.5 hp engine, am I thinking correctly or do I roll it out to the road for scrap??? This tractor was a gift with numerous issues, it is a flood survivor, I have pulled flywheel to check woodruff key, it wouldn't hold a constant RPM. This last carb as gov. kept moving back and forth, so I just accepted it and ran it, now??? yesterday, it started again with the popping, blk smoke, stalling and barley running, way over rich, wouldn't clear up for nothing sooo I ordered another carb just for gigggles. Any opinions?? I know it is an older mower, to be honest these are not that complicated but this type of carb to me is, especially the warning "Must be specific to this engine" so help!!
 
Well we have no model of the mower nor the engine's model, type code, and date code. But it does sounds like you don't really know what you are doing and are just guessing and throwing parts at it.

Every Nikki is tuned to a spec by the OEM. Carb jets are sized accordingly. On top these engine bad about blowing the head gasket. The constant surging after carb replacement was because you did not do a static governor adjustment or the carb was too lean.

The key here is you must know what you are doing and not just guessing at the problem.
 
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for a 4-cycle engine to run right, one needs fuel and air, spark at the right time, and compression. One or more of those is either messed up or varying. Your job as the mechanic is to figure out which one(s) are affected and how. It can be any of those three. And, it can be as simple as a bad spark plug. Or it can be a mouse chewed thru a wire that in grounding off and on. It can be old fuel or water in the tank. Shooting the parts cannon is not usually a financial winner. Start with one of the three and isolate what is causing it. Check the compression and valves to be sure they aren't too tight. Check the exhaust to be sure that it isn't filled with mud or carbon, that it is free and open, that if there is a spark arrestor, it isn't plugged with carbon. etc.. Pick one of the three and test it until you are satisfied it is not the cause. We have no ability to figure that out over the Internet - we can only make recommendations based on what you discover in your testing.
 
Ok lets go to my original question are these 15.5 BS low emission engines with Nikki carbs dialed in expressly for these 15.5 hp low emission engines, ??? that is my question.
 
Unless you provide us with all engine numbers it is extremely difficult for any of use to answer your questions. You don’t even supply us with the engine brand. Techs here are not psychic nor do we have a crystal ball so we must rely on actual facts such as engine numbers or at least unit numbers. Most Nikki carbs are jetted for a specific piece of equipment, not one size fits all. Reread your first post, as you started that. Second, most techs have found carbs purchased off FleaBay or AutoScam have less than a 50/50 chance of being the correct one for a particular engine. If you really want us to help you, you need to supply us with all engine and unit numbers, plus part numbers for the carbs you have purchased.
 
red423 said:
Ok lets go to my original question are these 15.5 BS low emission engines with Nikki carbs dialed in expressly for these 15.5 hp low emission engines, ??? that is my question.
Click to expand...
Since the mid 1990's, each carb is set up by the manufacturer to give a certain emission level on a specific engine. That is why it has an emission label on it - engine family etc.. The same model carb may have many applications with varying jetting. Fortunately a gasoline engine will run in a range of mixtures and not just at one specific mixture. Thus, a generic carb, with generic jetting may substitute on an engine for the original. The bad news is that unless you know the seller of a specific carb, you do not know its history. It could have been tried before and worked bad so someone returned it. Then years later it gets sold as a NOS carb. Likewise, if the carb you bought prior does not work right, you might return it, say to Amazon, and then it becomes someone else's problem who may experience the same issue you did. There is NO substitute for understanding troubleshooting on engines. ALL OF US have struggled with engines that do not run right. Sometimes replacing the carb with an original works perfectly. Sometimes it does not, but another identical to it works fine. I would look for vacuum leaks around the gaskets or intake manifold, head gasket etc.. The difference between a low emission engine and another may be as simple as different jetting, or perhaps the breather system, or maybe adjustments and defeat mechanisms to keep consumers from being able to retune the engine.

Go to James Condon's youtube channel and watch a bunch of his videos. You'll see a pattern emerge when troubleshooting carbs.
 
sgkent said:
Since the mid 1990's, each carb is set up by the manufacturer to give a certain emission level on a specific engine. That is why it has an emission label on it - engine family etc.. The same model carb may have many applications with varying jetting. Fortunately a gasoline engine will run in a range of mixtures and not just at one specific mixture. Thus, a generic carb, with generic jetting may substitute on an engine for the original. The bad news is that unless you know the seller of a specific carb, you do not know its history. It could have been tried before and worked bad so someone returned it. Then years later it gets sold as a NOS carb. Likewise, if the carb you bought prior does not work right, you might return it, say to Amazon, and then it becomes someone else's problem who may experience the same issue you did. There is NO substitute for understanding troubleshooting on engines. ALL OF US have struggled with engines that do not run right. Sometimes replacing the carb with an original works perfectly. Sometimes it does not, but another identical to it works fine. I would look for vacuum leaks around the gaskets or intake manifold, head gasket etc.. The difference between a low emission engine and another may be as simple as different jetting, or perhaps the breather system, or maybe adjustments and defeat mechanisms to keep consumers from being able to retune the engine.

Go to James Condon's youtube channel and watch a bunch of his videos. You'll see a pattern emerge when troubleshooting carbs.
Click to expand...
been watching cordon's channel for a long while, been there and done that many times myself, problem here is using my skill against getting information, when I search B&S carb models for this engine all I get are part numbers, not actual jet sizing, then by chance if I am lucky I will find posts of all Brigss carbs and jetting, then have to convert that sizing to my wire drill sets and it doesn't equate, see my isssue here, when this mower does start coughing and missing it is a definate carb issue I wasn't given it with the OEM carb it came with an ebay special and the air mixture screw was siliconed over. When I finally got mad enough to get a new carb yes it went from "Fits Briggs 14-17hp" on the listing, which to me being a retired wrench, sent up immediate alarms, After install the smell and blk smoke, wet plug when pulled indicated one thing, way tooooo much gas, now, is it the emulsion tube being sized for a 17hp, orrrrr the jetting sized for a 17hp, or according to TB the MAJOR warning on their manual I found that states "The 15.5hp is a low emission engine designed for lower emission and as such requires oem specific replacement parts" Hmmmm makes one think, did they actually design a fuel and valving system that was of lower emissions?? specific jetting and emulsion tube just for the valving design on this 15.5 which seems a "bastartd engine size and design to start????? Hmmmmm makes one think, In my time I have gone from Deer, Scotts, TB, Kohler, B&S, from 12hp murrays to twin 22 HP deers to the 33 HP gen set we have for hurricanes, all the way to a 25kw gen. with a water cooled mitsubishi in line 4 cyl. for a drive mtr. So you might understand, "just slapping a generic carb on this TB to me personally is an issue IF , and I say IF I cannot verify JETTING is the proper size for THIS specimen of small trailer tug I use it for. IS that a better summation of where I am right now??? I got a "Specific listed carb delivered last night, with new plug, and vacuum tube from fuel tank to carb with new a/f, after I drain all gas, change the coil, I will install new carb and see if the jetting allows for this engine, I have checked valve lash, checked PCV system, (yes it has one) no white smoke whatsoever, blk and major coughing when spitting, that alone says either valves, orr excessive fuel issue, I am leaning toward fuel as when I do get it to run at mid to high rpm's man that motor will run. Let me know more thoughts on specifics of these 15.5 carbs if you can and as always THANK YOU for replying to my posts, Even at my age, I still rely on opinions of others before I decide my fate...........red PS yesterday when it started running rough, I noticed the vac line from gas tank to carb had fallen off, replaced it and it took off running great then?? out of no where almost like it loaded up, blk smoke and that "too rich smell one gets" then back to coughing, I will see today, wish me luck!!
 
Apparently you just don't get it we must know the engine numbers as most Briggs Inteks were set up Nikki carburetors and those can be picky and hard for some reason for techs to understand. With the model, type/spec and datecode/serial numbers then I could look up the engine and see if it was using a Nikki. I do have several the main jet sizes [ part number to jet size] for these. That data base is only base on what I have personally come across. I have asked for the send me what they were finding but no would get off their can to help.

Now it is a Walbro or Ruixing carburetor I don't any those jet sizes at hand.

I have also come one Nikki clone where there was idle mixture jet even it had an adjustment screw. That one surged even after a static governor adjustment.

Nikki style uses main jets with rubber o-rings that becomes harden and loose which causes fuel mixture problems. Nikki carburetors also what a spaghetti bowl gasket and sometimes a separate inlet tube o-ring which can leak over time. I even seen some new bowl gaskets to be defective which is a 10x loupe can be of help to spot those defects. Even you remove the fuel on one that been used a while it probably will need replacing.

Plus an intake manifold seal can cause strange problems like one here that sounded like it was sneezing.

One even have one 21 hp Briggs Intek here last year you start up and ran very nicely until you engage the deck. Then it heavy surge constantly even with the deck disengaged. Believe or not it turned out to be a bad spark plug.
 
Red, I’m out of patience too. Why is it so hard for you to supply us with the engine numbers? In post #5 I explained to you what we need from you, but that simple request must be outside your knowledge capabilities. I’m getting out of this thread, because my head hurts banging it again your rock for a brain. You are in need of jet sizes, and we are in need of someone who can read and write simple numbers. I’m old and not to bright, but still at least a little smarter than you. Good Luck, although you need more than luck.
 
Okay which one of these 100+ engines?

310707-0137-E1
310707-0139-E1
310707-0136-E1
310777-0131-E3
311777-0005-E1
311777-0105-E1
311777-0141-E1
311777-0143-E2
311777-0162-E1
312777-0101-E1
313707-0132-E1
319775-0110-E1
319775-0111-E1
31A507-0120-B1
31A507-0121-G1
31A507-0124-B1
31A507-0141-B1
31A507-0742-B1
31A507-1391-B1
31A507-2471-B1
31A507-3405-G1
31A607-0117-B1
31A607-0118-B1
31A607-0118-E1
31A607-0126-B1
31A607-0127-B1
31A607-0132-B1
31A607-0140-B1
31A607-0145-B1
31A607-0149-B1
31A607-0151-B1
31A607-0155-B1
31A607-0741-E1
31A607-1190-B1
31A677-0119-B1
31A677-0150-B1
31A707-0116-E1
31A707-0121-B1
31A707-0525-B1
31A707-2454-B1
31C707-0026-G1
31C707-0160-B1
31C707-0230-B2
31C707-0230-E1
31C707-1346-B2
31C707-3487-G5
31E577-0114-G5
31E607-4140-B1
31E677-0150-G5
31E707-0129-E1
31E777-0132-B1
31E777-2439-B1
31E777-3137-G1
31F777-0105-E1
31G707-0026-E1
31G777-0105-E1
31G777-0130-E1
31G777-0135-B1
31G777-0149-B1
31G777-0156-G1
31G777-0238-B5
31G777-0293-E1
31H777-0115-E1
31H777-0119-E1
31H777-0210-E1
31L777-0123-E1
31L777-0126-G1
31M777-0167-E1
31N707-0026-E1
31N707-0301-G1
31N707-0430-E1
31N707-0840-B1
31N707-1374-B1
31P607-0114-B1
31P677-0117-B1
31P677-0140-B1
31P677-0144-B2
31P677-0825-B1
31P677-0832-B1
31P677-1373-B1
31P677-3140-G1
31P677-3373-G6
31P707-0126-B2
31P707-0241-B5
31P707-0244-B1
31P777-0115-E1
31P777-0120-B1
31P777-0125-E1
31P777-0143-B1
31P777-0155-B1
31P777-0602-B1
31P777-0770-B1
31P777-3202-G5
31Q677-0125-B1
31Q677-1629-G5
31Q677-3493-G5
31Q777-0113-B1
31Q777-0117-B1
31Q777-0122-G1
31Q777-0137-G5
And this don't even the new 31R series. Every engine is tuned different depending what required spec was.
 
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