Mariner 3.5 2-Stroke not developing power

[Rich_F]

Any Ideas? I've got a Mariner 3.5 2-stroke that starts well, idles nicely, but stalls if the throttle is put over 20% while in gear. It's happy to be revved when out of gear.

My winter project is to dismantle and re-assemble it, which should eaither fix the problem or kill it completely. But are there any less 'scattergun' approaches to resoving this problem?

CLUE: Earlier this year, it stopped working completely and refused to start. So I stripped down and rebuilt the carburettor, and since then it has been displaying the symptoms described above.

Thanks,

 

[Kawasaki]

The symptom sounds like the motor is being deprived of fuel under load.
This can happen if the fuel level in the float chamber is too low. or the float itself is sticking.
Some carbs have a float that can be adjusted.
Carb off, float bowl off, blow into the orifice that lets fuel into carb whilst moving the float up and down slightly to see where she"Sits" as the air flow stops.
IE when the float has "risen" to a level what stops yer blowin goin in the carb!
Rule of thumb the float will be about "level" or a tad more.
This allows the bowl to have enough jiuce in it when needed.
If the float is adjustable it will have a metal bit that pushes against the fuel needle, this can be physically adjusted to change the float level.
IE when it shuts the fuel off. do not use a lump hammer.
The eng appears to run ok in the tub, indicates the main jet is clear but check all jets and orifices . Carefully probe with something like the hair off a wire brush,gently mind no lumpies again .
Also good to blow down said holes etc with an air line.
Another totally different happening.
If the drive shaft of said gadget is starting to seize where it leaves the Powerhead similar will happen.
Although it may run ok in the tub in nuetral, when asked to work underload and has become warm eng will want to stall.
Hope its a petrol prob.

 

[cliff]

Blocked main running jet? - Do the wee tohatsus have one? /forums/images/graemlins/confused.gif
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"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>

 

[Kawasaki]

Be the one the carb slidy thing uncovers , main orofice or chief atomising groove?
Never pulled one apart, must have summat you can poke at! "Dianostics From A Distance R Us" /forums/images/graemlins/smirk.gif

 

[yoda]

Check the carb (blow through the jet because it can look clear but have a restriction that would cause your symptoms. Also check the filter which is on the fuel tank stop valve. Remove the valve from the tamk and you will find it.

Yoda

 

[gandy]

Suggest checking the float height, and check again for crud in the carb. Also check free flow from the fuel tap to the carb. I got exactly your symptoms (start and tickover fine, won't run at high power) when I got water in the fuel tank.