Briggs INTEC twin 20 HP - loading up on gas

Have a zero turn Cub Cadet with a 20 hp Intec twin cylinder engine. Sometimes it sounds like it is running OK, then at other times it sounds like it is getting too much gas and sort of flooding out. If you shut it off it doesn't really want to start well, until you crank it enough, sort of like it is flooded. Crank it long enough and it will begin to fire and run. Might have a little fuel vapors in the muffler (like it is running rich) when you shut it off as sometimes it will pop. I have disassembled the carb and did put a new gasket set into it. No adjustments on this carb., at least no main jet adjustment. Only 111 hours on the engine. Any ideas????? Thanks.

Did you check the float setting and make sure it moves freely when you had it apart? Have you checked to see how good of spark your getting?

If you haven't done so already replace both spark plugs,you may just have a plug going bad & dropping a cyl when eng running,if that doesen't cure problem install an inline spark tester in each plug lead,when eng starts to act up or when trying to restart eng check that you have spark on both cyl to confirm you don't have a coil going bad & breaking down from heat as this eng uses a seperate coil for each cyl.

If ign system checks out ok then most probable cause is a problem in carb or air leak at carb gasket or intake manifold mounting gaskets.

A couple of left field possible causes valves sticking in guides when eng hot due to carbon buildup on valve stems or carbon buildup on valves/valve seats,loose valve seat(s)or a head gasket that's starting to leak when eng hot.

Sounds to me like the fuel shutoff valve isn't working. Mounted to the carb bowl should be a very obvious "hootus" with a wire to it. It is a fuel flow valve. When you turn on the ignition this valve is supposed to open allowing fuel to flow into the carb so that the engine will run. When you turn the key off it is supposed to shut off the fuel to the engine so that while the engine is decelerating to 0 rpm with no spark, it doesn't continue to suck fuel into the combustion chamber causing hard starting the next time and ultimately, just before 0 rpm, a POP in the exhaust system which is raw fuel against glowing exhaust components igniting. Now how do you suppose I know that?

So, I'd check to ensure that the 12v to the switch is in fact gone when the key is off which it would have to be or the thing would run your battery down if left sitting for like a week or so, or the switch is not closing as it should. With 100 hours on the machine sounds like a manufacturing defect and could be as simple as a piece of metal left over from the machining or installation process didn't get removed and is jammed in the switch mechanism.

First off both of my Briggs twins do NOT have fuel shut off solinods. Next is to look at the carb. Is there a metal plate on top that kinda looks like two triangles joined together? This is the better carb and is a NIKI carb. If you look at yours and it is a round carb JUNK it and the manifold both. Find your friendly local lawn mower repair joint with a nice big pile of stuff out back and tell them your problem and buy the older carb with that plate. Different manifold too. Will bolt right on to your engine. The older carb is actually TWO carbs in one with a carb for each cylinder. NIKI carbs when working correctly are great. If you do not use Startron the ethanol chews up the gaskets and "O" rings in the carb and the problem you described is what happens. NOW the twin carb is repairable with very little trouble. The kit is not cheap but you will need to replace the two main jets. They MUST fit tight and the "O" rings get brittle and fall apart. The carb is a sort of closed loop system and everything gets out of balance if the main jets leak. If you pull up the explosion for the NIKI carb they are item #117. From Briggs they are about$6.oo each. Very simple rebuild and afterwards they run GREAT! While you are at it blow out both sides of the engine to remove ALL of the crud!!! Last thing to look at is where the carb and manifold join. The under side can warp. Take it apart and clean. Some silicone tub seal will fix it. Made these repairs on one of my machines and two neighbors units. ALL are singing a happy tune now. Just letting you know...the two screws that hold on the bowl are a B witch to get out. Use a NEW screw driver that fits tight and give the end of the driver a good sharp wrap with a small hammer to break the bond. Push hard on the screw and give it a sharp CC snap turn. That should do ya. Get back to us!

P.S. These engines run SOOOOooo much better with Hi-Test gas! Also use Startron!.

jeffcat do you know where you can get just the O ring for jets. Brother in law has a 24 HP and nobody around here had or could get O rings and he ended up buying new jets they have O rings on the new jet. I have been using Stratton in every thing that doesn't get used a lot and sets over winter. I have put fuel shut offs on all my garden tractors and run them dry every time I'am done using them.

GOOD man....run them dry at end of season. Startron is fantastic! NOW for the "O" rings. GOOOOOOOD luck! Every repair and supply place I know has had ZIP finding them. The rings also need to be gas tolerant. Just buy the new jets as they are not that expensive and I use a dab of silicon assembly lube they just pop into the holes. When they become brittle they leak and throw the carb all out of adjustment. Have fixed three of these NIKI carbs and everyone just purrs now. As I said you want the carb with that two triangles glued together type carb. The single one is a NIGHMARE !!!!

I think the Walbro carb is much better than a Nikki

Thanks for the ideas jeffcat. I will have to look at my carburetor to tell you which one I have. I have had it apart. It does have the electronic fuel shut off on the bottom. I am pretty sure there is no "main load adjustment". I remember when I took it apart that the gasket between the main parts was sort of a rubbery string like thing that fits in grooves in the casting. I also remember that there was sort of a "nozzle" that fit into maybe the upper casting that had an "O" ring on it. I sort of wondered if it actually sealed things off very well. So, is the carburetor I am describing probably the "bad" one. Are you saying no matter what this one can't be made to run right and that I should go for the "two separate" carburetors in one??? Maybe I should send my carburetor to you for a rebuild. Thanks

That is what I thought too. Was going to buy a Walbro after I tangled with the single ventura NIKI. Two very good repair places BOTH said to fix the twin NIKI. The Walbro needs a different manifold mount. It is also a single ventura as where the NIKI is a twin. ALso a WHOLE lot of bucks!! Like before, if you get the kit and fix it correctly the NIKI carb work just great! My $.02 but I am very happy with them.

O CRUD that is the crap one! That little stingy gasket is like $8.oo on flea bay! Also , when you take the bowl off and all of the stuff falls out.....I bet you lost the little tube. I did. Maybe not but JUNK IT!!!Go to Utube and look up {How to repair Briggs and stratton niki twin engine.carb] . There are a whole bunch of videos on there. I only watched one for a few minutes at work. Check them out. As I said you want that bigger one with two venture Not the screwey one you have. Trouble is you need the manifold too so visit your local junkie type of repair place and buy everything. Keep getting back to us.

Jeffcat - I had to put a new nylon gear on the starter today, so you have to tear off the shield on top of the engine. Of course the left side was full of the remains of a mouse nest. Anyway, when I took off the cover over the air cleaner and looked down into the carb, there was liquid in the bottom - I assume gasoline. I think I have seen that before and it gave me the idea that it was running rich. Maybe after I get the starter running, and finish the lawn, I will tear into the carb again. Thanks.