Troybilt tractor, Briggs 31C707-1346B2...Nikki carb...

[bgsengine]

So, checking cold won't pinpoint a gasket leak...but it runs only on full choke when it's cold too...no changes when it warms up. Also, yes, there is a solenoid in the bowl of the carburetor...I did check it, it's getting fuel...or I assume it wouldn't run at all...

Solenoid does not control fuel into carb, it ONLY controls fuel to main jet Engine could still run on the idle circuit provided it was at dead idle *OR* on full choke. That is why I asked - You want to make sure solenoid is properly hooked up , and getting energized to allow fuel to flow to main jet after engine starts.

[KE4AVB]

Ah here is something to check and it is going to sound a little crazy but I have seen a couple engine to have it.

Check the valve lift on the exhaust vavle, Both rockers should be moving the same amount. I have seen the exhaust lobes worn nearly round.

[dart451]

I'll double check the solenoid function today and also check the exhaust valve rise...see if it's the same as intake...thanks...

[dart451]

Finally figured out the problem! Checked the solenoid, getting 12v when key in run position. Solernoid activating. Engine was doing the same thing. Tried the old carburetor again, wouldn't run at all. Tried another new carburetor that I had, WALLA! Started right up, runs perfectly! So, I apparently got a faulty new carburetor but I bought two of them... I want to thank everyone for helping me with this project...spent days trying all sorts of things finding it was a stupid bad carb!

[bgsengine]

Finally figured out the problem! Checked the solenoid, getting 12v when key in run position. Solernoid activating. Engine was doing the same thing. Tried the old carburetor again, wouldn't run at all. Tried another new carburetor that I had, WALLA! Started right up, runs perfectly! So, I apparently got a faulty new carburetor but I bought two of them... I want to thank everyone for helping me with this project...spent days trying all sorts of things finding it was a stupid bad carb!

Perfect example of "New does not mean Good"

[38racing]

I just has similar puzzle. Sitting briggs 28 only ran on carb cleaner. I redid carb. (Also bought new one in case) Had to destroy nozzle to remove. Putting back I replaced all fuel line, put on a new filter and added shutoff. Still would only run on carb cleaner. Before pulling anything I removed fuel line from carb. No flow. I had just grabbed a shutoff from my fuel stuff container. Outlet on it was plugged solid with something. New valve, runs great.

[SUKI]

Finally figured out the problem! Checked the solenoid, getting 12v when key in run position. Solernoid activating. Engine was doing the same thing. Tried the old carburetor again, wouldn't run at all. Tried another new carburetor that I had, WALLA! Started right up, runs perfectly! So, I apparently got a faulty new carburetor but I bought two of them... I want to thank everyone for helping me with this project...spent days trying all sorts of things finding it was a stupid bad carb!

A couple OEM @$100+ each or a couple clones? PN 594593. OEM return it as defective, Clone just chunk it and learn to leave clones alone.

[Arkie]

New does not always mean pl;ug and play especially with the Nikki clones or even Nikki kits into OEM Nikki's.

If you got it from Amazon Prime you can return for a full refund including return shipping as free. (usually)

I keep a good Walbro LMT carb on the shelf as a test carb for the 28, 31, and 33 series Briggs engines and as KE4AVB mentioned I had a 31 series that would not run correctly cold and would get almost perfect run after warmsing. Installed the Walbro LMT and same engine symptoms. I can usually make a Nikki carb run ok if I know for sure the engine issue is with the Nikki carb, but if a new Nikki clone carb won't perform correctly you are usually wasting time trying to make it correct. (you have a China rejected Nikki from a vendor that deals in such)

Did notice a slight spit back through the carb when engine was cold. Compared valve lift and noticed the intake valve lift way off.
Long story short the intake lobe on camshaft was worn down.
I had a good camshaft with a bad ACR so I took the two cams and made one good one and got a good engine run.
Posted the results on this forums sometime back.
More Briggs 31 series experience.

[38racing]

watched a video of guy changing heater coil in a ram. first 2 new ones leaked.

[bgsengine]

watched a video of guy changing heater coil in a ram. first 2 new ones leaked.

LOL.. if it was a 90's or early 00's dodge, a 7 hour job , done three times.. not fun.. and if the tech was on flat rate, he got seriously screwed. I never had to re-do one, thankfully, but even doing it once was a royal PITA.