Backfiring out the carb

On my bolens it has a 16 hp tecumseh on it. I rebuilt and cleaned the carb and now it runs like crap. I made sure I put everything in exactly the way it was and now I can't get the revs up from idle. Or it backfires out the carb and shuts off. I read a myth online about not taking out the jets in walbro carbs because they will never run right again because apparently when the made those carbs they drilled the idle circuit after the jet was installed. Anyway I don't know what to do and I need help :/ my carb is a walbro lmh 32. I really don't want to keep that carb cause a friend of mine said a kohler #26 would work on it but I'm not sure.

i believe thats the same carb that my tecumseh has. honestly, to me it seems like its out of adjustment. screw with the adjustment a little. backfiring out the carb, i beleive thats too lean, so turn out the high screw a bit

I've tried everything honestly. I've been messing with it all day and can't get the darn thing to run right. And under load it hesitates really bad. I think the governor rod might be out of adjustment as well. Would you happen to know how to adjust those?

youre sure you assembled everything correctly, like the governor linkage in the hole it came out of, make sure its not bent. on mine, there is no adjustment of the governor. also, if you didnt replace the intake gaskets after removing the carb from the block, you might be sucking air from around it. a quick simple test for that is to spray carb cleaner or equivelant around the carb and block where they meet. if it picks up, you need gaskets. if no change, its something else

Yea it's got everything put back together correctly and it has a new intake gasket. Like I said it might be the governor linkage that's not adjusted correctly I just don't know how to adjust them on the tecumseh engines

if you put everything back together the EXACT way it came appart, why would the governor be fine, then boom- out of adjustment. like i said, i dont think there is a way to adjust them on these engines

True. I recently got this tractor 2 weeks ago and the guy said it didn't run right. And the carb and fuel lines were off of it and I'm piecing it back together. So i don't know what all could be the problem

does it have a fuel pump or pulse line? Is that all hooked up if that is the case?

It has a fuel pump that screws into the side of the carb.

there should be 2 lines going to the pump. mine was setup the same way. there is a line going from the crank case, to the bottom of the pump, and then the a line coming from your tank going to the other spot on the pump, should be sticking out the front if i remember correctly

Yep that's how mines setup. I think it's a walbro 3001 fuel pump

yup, thats what mine was, then if started flooding my case, so i promplty sent it sailing into the woods, and retro-fitted a new style mikuni pump to it. NOW, back to your issues

Well that's not good was your diaphragm in the pump ripped? And yea I'm not too happy with the tractor right now lol it runs fine at idle for like 5 minutes then backfires out the carb and sputters and shuts down. Now if I leave it running at idle and try to throttle it up a bit like halfway or full it hesitates real bad and backfires out the carb and keeps doing it

yeah, i presume the diapgram had a pin hole or something in it. now, based on what you just said, tells me that its starving for fuel. it almost seems to me that the bowl is able to fill, but gradually will run out and cant keep up with the useage. have you replaced or cleaned the fuel lines at all? id start by replacing the inline filter, and blowing compressed air, backwards, through the system. obviously, remove the line from the tank so any scuz that does come out dont go back into the tank. put the end in a bucket so you can examine what, if anything comes out. thats where i would start, then clean the carb again, make sure the float isnt hanging up in the closed position, make sure the needle is moving freely, and lastly, id do a gravity feed with the bowl off to make sure the fuel is even getting to the carb

Yea I put new lines from the bottom of the tank where the fuel shutoff is to the inline filter then to the one side of the pump. I did wash out that tank and drying it real good. Here's a dumb question does the arrow on the inline filter go toward the carb or tank?

it indicates the flow of fuel, so toward the carb. really, it dont matter, i just put it that way so i can see when its getting dirty, but ive seen it both ways

Oh ok. Now How would I be able to get more fuel to the carb itself?

really, the only way to do that is to get a bigger/new pump. over time, these pulse pumps DO wear out. i'll get pics of how i set my new pump up tomorrow if you want

Yes that would help out a lot! Haha i hope it's the pump

First the problem, then your myth...

Check your timing key!!! Shartin' thru the carb is a CLASSIC sign of an engine that's out of time!!! I'm going to bet that you did not correctly torque down the flywheel nut, and the key sheared...

Now- the carb myth you speak of. It's not a myth. It's actually in the Tecumseh service manual. Simple, huh? That said, I've broken down many affected carbs, and not had to order a replacement. Luck maybe, don't know. But it's no myth.

Well besides the carb being off of it I haven't touched anything else and with the shaft that goes from the flywheel to the jackshaft I don't have much room to check that timing key out

Dipshaw87 wrote:

Well besides the carb being off of it I haven't touched anything else

Perhaps a previous owner then, or fluke. Either way, check it. If I had a nickel for every time I saw this, I'd be loaded!

Quote :

and with the shaft that goes from the flywheel to the jackshaft I don't have much room to check that timing key out

You have to gain access to the flywheel to check the key. So then, the question becomes, "How badly do you want to solve this problem?". There's a chance it's NOT the key. But you troubleshoot by eliminating things.

You got a point there I'll check it out here in a little bit

good catch doc, i completely missed the flywheel key. thats why we have forums though, teamwork

this is how i set mine up, mine is a 10 horse, smaller carb, but same family of carbs. so, it should work for you.

i removed the fuel pump that was threaded in, and put in a 1/4 inch brass nipple.


i got a new style Mikuni pump from "jim micco and sons on ebay" for about 15 bucks



ran a line from the crankcase breather, about 6 inches long, then another from the filter to the intake on the pump, and then another, about 12 inches long to the carb.




this setup has never let me down, even hanging freely like it is. when i paint it for the buildoff, i plan on fastening it to the shroud, and making everything pretty