Same dingo different problem

[Jackshaft01]

Alright boys need some advice again…
Same 301cc runs great, kinda. If I push the throttle like a normal person it runs fine. If I stomp the throttle it bogs and dies (from idle). I’m thinking pilot/low rpm jet. I’ve tried switching main jet to larger size but has a negative affect(bogging/dieing). Second hand motor so not sure what if anything has been done to idle jet. Any thoughts? Do people usually replace or drill the low rpm/idle jet out. Emulsion tube to small?
Motor 301cc
Mods. Gov. Delete, oil sensor delete, Aluminum flywheel, header pipe, carb stage one pod filter and possibly main jet upgrade.
Not sure about main jet previous owner installed it. I did try a .42 and .43 and it ran like crap so put the original back in.

 

[Edwin Spangler]

Try putting a more restrictive intake back on...

 

[Hellion]

If I stomp the throttle it bogs and dies (from idle). I’m thinking pilot/low rpm jet. I’ve tried switching main jet to larger size

Please share some photos of the carburetor type, intake manifold and pod filter, or your engine in general for reference but the science is the same regardless.

Engine idles fine so the low speed circuit is fine. You’d have trouble getting it to idle or start if the low speed/idle circuit was faulty. I’d say you need a larger main jet so it will supply a little more more fuel into the intake as you gas it. You might need a whole set of jets that you can progressively add to the carb to test it, in order to find the right one for your engine.

On an automotive carburetor with an accelerator pump, it literally dumps raw fuel into the intake, like from a little spigot and not a finely metered jet. Anyway, what that does is it bridges the gap between a nice idle and a savage stomp of the pedal, otherwise the engine will bog and fall flat on its face.

Beware of these “silly” Stage 1/2/3 mods. If you don’t build your engine for higher performance that the kits provide, with stiffer springs, timing, piston, porting the head, compression ratio, etc., the Stage 1 mods are basically just window dressing. Those sellers make a lot of money selling those kits though.… I learned that here on DIYGK mostly.

Not sure about main jet previous owner installed it. I did try a .42 and .43 and it ran like crap so put the original back in.

You need to be sure of this. You may need to start all over on this build or simply follow someone else’s work. What do you mean it “ran like crap”?

 

[Jackshaft01]

Alright so I took the day to diagnose the issue. As I suspected the low rpm/idle jet was to small. I had ordered some mico drill bits the week before and used them. So the engine would run great the only time I had issues was when I would stab the throttle. (Stock 301cc carb). Plug is what gave me the suspension of issue. It was nice coffee brown but had a little white on the tip. I ended up opening the idle jet 2-3 sizes. Only reason I say that is because I didn’t have one that fit without resistance but was close. Greatly improved low end power and take off. If I completely slam my foot on gas she has a slight “cough” but besides that it’s perfect.

 

[Jackshaft01]

Please share some photos of the carburetor type, intake manifold and pod filter, or your engine in general for reference but the science is the same regardless.

Engine idles fine so the low speed circuit is fine. You’d have trouble getting it to idle or start if the low speed/idle circuit was faulty. I’d say you need a larger main jet so it will supply a little more more fuel into the intake as you gas it. You might need a whole set of jets that you can progressively add to the carb to test it, in order to find the right one for your engine.

On an automotive carburetor with an accelerator pump, it literally dumps raw fuel into the intake, like from a little spigot and not a finely metered jet. Anyway, what that does is it bridges the gap between a nice idle and a savage stomp of the pedal, otherwise the engine will bog and fall flat on its face.

Beware of these “silly” Stage 1/2/3 mods. If you don’t build your engine for higher performance that the kits provide, with stiffer springs, timing, piston, porting the head, compression ratio, etc., the Stage 1 mods are basically just window dressing. Those sellers make a lot of money selling those kits though.… I learned that here on DIYGK mostly.



You need to be sure of this. You may need to start all over on this build or simply follow someone else’s work. What do you mean it “ran like crap”?

Rich bog and dieing

 

[Jackshaft01]

Here is my set up. Hard to see.
I have put correct belt and silencer from gps on her since