G2 Reed/Speed Carb Idling Issues

sockeye101

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Updates!

Ok try this, get some masking tape & piece of paper, cover your air filter up, where only a 1/4-1/2 of the element exposed. See if it goes to idling right.

I started with this one. While taping the air filter didnt seem to do much, on a whim I reinstalled the stock Speed Carb air filter. Dropped in a new plug to check the colour as well. Loss in max RPM/overall power was immediately noticeable, throttle wasnt providing much response past around 5000 on level ground (revs out to 8k normally), but idling did improve slightly. I reduced the jet size to a #85 and was able to maintain a good idle with the needle clip in its second-highest position, however the plug looked very lean after a short ride. Is it possible I need to jet up and change fuel / oil ratio to increase fuel/air ratio? (currently running 1:32 synthetic 2-stroke oil)

Start it up, get it warm and then let it idle until it quits. Pull your plug and see if it's wet or dry. That'll tell you how much fuel at idle.

That carb is a good one, I've used those in the past with good results 5 Five, FIVE connections between the cylinder and the carb.

Tried this as well. The new plug was wet, but I may not have let it warm up enough first unfortunately. Hard to tell at idle though, the engine doesn't seem to get very hot if its not being revved or put under load.

I also forgot to mention, I had the float set to a slightly richer position (about 1mm from the top of the carb), but I suspected the idle mix was too rich and causing it to die at idle for that reason. Ever since resetting it back to 2mm though, I have been getting surging when letting off of the throttle (followed by it dying again), so it might be too lean now. Was using the information located here to tune it.

The only other symptom I picked up on that I didn't notice previously, was that as it idles and starts to die off, opening the throttle causes the RPMs to jump for a split second before immediately bogging/dying, unless I feather the carb open and give it time to pick up more fuel. This, combined with the float position is making me suspect that my idle mix is too lean currently, thoughts?

Didnt get around to swapping the CDI yet, but that's on my do-do list for this weekend.

As a complete side note, has anyone here experienced moisture buildup and condensation on/in your carburetor? It seems as though the top of the slide is getting very damp, to the point where some rust and a fuel/water residue forming on the top of the slide. I don't believe the gas has any water in it, but we are in the wet season and I'm wondering if that high-flow air filter is allowing too much rain/humid air into the carb. I'm also located on the coast, so there is of course quite a bit of salt in the air year round.

Thanks for the tips so far folks!
 

Chainlube

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You're getting too much fuel, that jet is too big and it's flooding the engine. That's why it won't idle.
The proper way to set the float height is with the carb upside down and from the seat it should be 21mm.
float-level-21mm-jpg.23596
 

DAMIEN1307

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Thanks for the tips so far folks!
You're getting too much fuel, that jet is too big and it's flooding the engine. That's why it won't idle.
The proper way to set the float height is with the carb upside down and from the seat it should be 21mm.
float-level-21mm-jpg.23596
That float needs to be measured the way that @Chainlube has just explained it, The stock jet size for that is supposed to be a #70 and initial needle valve setting should be with the C clip in the middle position at or around sea level altitude...That #85 jet is much to large, especially if your at or around sea level...Plug gap also needs to be around .025 thousandths.
 
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