Engine dies at all speeds

Seems like your are describing a outboard motor. If so, the Boat section of Fixya may have more experts that you need. You would want to avoid turning any screws on the carburetor body. The externals on the linkage have some adjustments like throttle stops.

The linkage on boat shift mechanisms are tempermental. They usually combine 2 functions on 1 control lever. They are synchronized that when the transmission shifts from neutral to forward and neutral to reverse the idle speed is low. This keeps the gears from grinding and takes the shock out of the shifting process.

Another thing different than on a car engine is the effect of the propeller on engine rpm. You can change the "in gear"
rpm for both directions by changing prop size and/or pitch.
This also means you can over-rev the engine by having the wrong prop on the boat. There are engine rpm "stops" for the high end too, but some just rely on using the correct prop. As what you may be experiencing with a "stall" can be brought on by

A word of caution. The inboard/outboard engines can have the same problem as outboard engines. The shift levers are synchronized with a pivot system and adjusting the throttle can interfere with the shifting.

You may be able to view youtube videos by searching for these topics.

It might be a blown head gasket!

If you a mechanic friend, ask to check the fuel pressure. It will tell you what is wrong.

Check for vacuum leaks on all hoses underhood. Make sure all intake componets are intact and they are tight.

Is the check engine light on? If so, get to an auto parts store, they should pull the codes for free.

Sounds almost like a bad throttle position sensor. The computer uses the TPS to help know when to shift on this car if I remember right, and if the TPS is bad, it can cause that jerking. Along with the car dying when slowing down after driving. But check everything else out first. Including electrical connections.

I had similar problem. My car died at every red light, unless I shifted to nuetral and reved it. Check oxygen sensor, it solved my problem.

You've got to do the obvious things, look at your spark plug wires, if you see what looks like chalky residue they are arcing replace them and your plugs. Check all vacume lines for leaks, and make sure your air filter is clean

Here is the common cause of surges, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

Check for spark during the stop .. if possible.. Most ofen this is the crankshaft sensor.. very common for this engine.. sorry.. $200 to replace...

I cannot see how adding a fuel additive would help to be honest. I would be looking for a split or leaking vacuum line, I have even seen a leaking evap canister before that caused a similar problem. Does the engine pull clean and strong when it is warm or at cruising speeds? Does it feel like its running lean or misfiring?

hi,i read your problem,for my opinion,maybe camshaft or crankshaft are the possible causes,to make sure, you have to bring the unit to authorized workshop to avoid guessing which part are defective