what is missing in my carb???

[rickf]

With 7:1 compression there is absolutely no need for premium gas unless you want to spend the extra money. The extra octane has nothing to do with how the gas starts or runs in low compression engines. All the extra octane does is prevents preignition in high compression engines.

[muttero]

Hi friends,

Thanks all for the help.

It seems that there is a lack of a return line from the top of the carb, where the screw is. When the engine is on, there is no problem, it runs good, it almost reach the 60 miles speed!!!

thanks again for your help!!!

[muttguru]

It seems that there is a lack of a return line from the top of the carb, where the screw is.

Muttero, If I remember correctly, you have an M151A2 and the fuel tank is an "emission-controlled" type, yes?
You also have an emission-controlled carburettor but you have no fuel return line, yes?
Your vehicle is hard to start when it has stood unused for a few hours, yes?

There are several possible reasons why it is hard to start.......... check these.....in this order....
1. You are not using the choke correctly (or the choke is not operating fully). Take off the rubber air hose from the carb. Get someone to pull out the choke button while you watch at the carb. Make sure the choke flap closes fully when the choke is pulled out. If the inner or outer cables are not securely fastened, the choke will not operate fully and it will be hard to start the engine. A cold engine needs choke.
2. The starter is not turning the engine fast enough. You should press the clutch pedal down fully when pressing the starter button.
3. That in-line fuel filter sits above the exhaust manifold. It will collect the heat from the manifold and will cause the fuel in the filter to expand. You have NO fuel return line, so the fuel may be pushed back towards the tank. If the fuel pump valves are old they may allow the fuel to drain out of the fuel pipe. Install a fuel return pipe. And take off that fuel filter....or relocate it nearer the fuel pump.

Try each step above, in this sequence. Then report back to us here with your results.

Ken