bogging at speed. By mhyquel (Read 312 times)

[mhyquel]

My 2009 benzhou developed a problem recently.
Starts fine, runs at low speeds fine.
When I try and get above 30kmh it won't rev higher. It starts bogging down, and sputtering. 
I've stripped the carb down, totally clean.
Its getting a good spark, air filter is clean.

Please help!

[jvino]

What size engine is it? to the sight alley or bashan will jump on this soon.

[mhyquel]

Hi Jvino,


It's a 150cc Saga, made by Benzhou.

It has ~6000km on it. 

[adamhoyer]

Remove the fuel tube from the fuel valve. (1) Fuel tank empty
supply (2) Fuel tube or fuel filter clogged
(3) Fuel tank cap air hole clogged Trouble shooting manual said this.

[Bashan]

Did you pull the jets and inspect the tubes? It sounds like the low speed jet is working but when it transfers to the high speed it's not getting gas. Did you carefully inspect the slide diaphragm? If it has a hole in it the slide won't pull up and ergo no gas for mid to high range. The other thing that can cause bogging is vacuum leaks. Check for leaks around the intake manifold and make sure all of the vac hoses are hooked up and not leaking. Then make sure there's no leaks or unplugged openings on the air filter side. Last, pull the plug and tell us what it looks like. Black, brown, naked, what color? Yes, the gas cap vent or filter can cause these symptoms too. Rich

[mhyquel]

Jun 11, 2014 11:57:03 GMT -6 Bashan said:

Did you pull the jets and inspect the tubes?

Pulled the carb apart and put it back tonight.


Tubes and jets look fine. Slide diaphragm is good. Spark plug is a little black, and dry. Seals on manifold are good. Tried with the tank cap off, and still has issues. 
Filter and air box are good.

 Runs perfectly fine at low rpms. When I give it full gas, it stutters.  With bursts of ignition. It will also stall and die after running for ~10 minutes. Starts up fine after stalling.

[Alleyoop]

First thing IS WHAT DID YOU CHANGE or do that started this problem?
Alleyoop

[mhyquel]

The problem started when I bought gas from Safeway. I've since a tank through though.

[Alleyoop]

What it sounds is happening is the diaphgram is not holding up the needle out of the main jet. Which would mean the rubber part on the diapghram is leaking. so take the top of the carb off and pull it out and hold it up to the light and look for any pin holes and or rips. Some leak around the center where it is held onto the cylinder. What happens is you have the throttle BUTTERFLY wide open and the needle is not rising out of the main jet so all your getting is AIR not enough fuel.
Alleyoop