4,5 hp 2stroke

[journeymanjohn]

i recently bought a 4,5 hp blueband and i cant get it to start. i replaced the fuel lines, fixed the fueal pump, fixed the electronics, checked spark. It still doesnt start, and doesnt even pop. so my next step was the carberateur but i cant get it out, any tips?

 

[racerone]

Does spark jump a gap of at least 1/4" , yes or no?

 

[fitz73222]

Is it a single cylinder, metal cowling or a two cylinder gnat, plastic cowling? Both are blue band 4.5's.

 

[racerone]

I assume it is the single cylinder model.----Those carburetors are tricky to take off for the first time.----If spark is strong it should at least pop , even with a defective carburetor.----Waiting for input from poster before the next steps are suggested.

 

[journeymanjohn]

@racerone i dont know if the spark jumps 1/4 (i live in europe) how do you suggest i messure that?
@fitz73222 it is a single cylinder, and i believe a plastic cowling

 

[racerone]

Does spark jump a gap of at least 6 mm?-----Put 6 drops of fuel in the cylinder.----Put sparkplug back in.----Try and start it.----Report exactly what happens.

 

[journeymanjohn]

IT POPS!! i am so happy i have been struggling for half a year now to even get here. So it popped but i had partly dissassembled the carberatur so it didnt go any further then that.

 

[journeymanjohn]

it popped very softly btw

 

[racerone]

Sounds like a lack of fuel then.----Post the actual cylinder compression valu.----And look into poor crankcase compression.----Bad upper and lower seals.----Reed valves?

 

[Texasmark]

Put things back together if you have them apart. I had a red band 4.5 single decades ago and don't remember if there was a cover over the carburetor intake or not....if there is one, remove it so that you can look straight into the carb. Set the throttle to wide open (full RPM position) and have the choke open.


With a can of "starting fluid" WITH lubricant, or Sea Foam Spray....which contains light mineral oil too (auto parts stores carry it), spray a couple of squirts into the Venturi (opening in the front of the carburetor). Pull the starter handle briskly several times. If it hits it will only run for a second or two (till it burns up the spray) but it tells you that your problem is lack of fuel in the carburetor Venturi. The question then is what is preventing this from happening...carburetor internal problem or supply problem....and does your choke lever close off the baffle fully when pulled all the way out?

Easy to check for fuel supply or carb problem. Remove the fuel inlet hose at the carburetor. Squeeze the bulb on the fuel line. If fuel shoots out the hose when you squeeze the bulb, the problem is in the carb or choke system.