New Predator 79cc only idles...no rev at all.

[Kenny'sID]

I just installed this on a trike and it starts fine but won't rev at all.

I've worked on these all my life off and on, even took an unnecessary small engine course way back when but this has me baffled, at least before I get it all apart and look closely. Been awhile since I worked on one but I see no air/fuel adjustment at all. There are adjustments on some of these in pictures online but mine has a welch plug where the adjustment should be. Not even sure that's the problem because I did use the choke to temporarily adjust the air intake for troubleshooting but no change. There is what looks like an adjustment screw w/spring at the bottom, but it was tight and backing it out only gives way to gas flowing out, as if it's some type of fuel drain. No flooding and again, it starts right up, seems to idle a little rough, and very little change when I move the throttle all the way to rabbit.

It's brand new and as if they messed up when they assembled something. Before I send the back to Harbor Freight, if they will even take it back. Ordered online but this is my only transportation and it's an 80 mi or so round trip to their store so that's out and I read they don't allow shipping back anything that had combustible fuel used in it, even if drained, so not sure what's up with that but I did email them. IOW, because of all that, plus it was a pain to install, it'd be nice if I could just get it going.

Before I yank this thing for return if they will let me, or pull it all apart to see what I can see, does anyone have any idea what the problem could be? Thanks

 

[Midniteoyl]

I take it that you have checked that the choke is fully closing and opening, and that the throttle plates are doing the same? Have you pulled the spark plug and determined that it too was ok and gets a full, consistent spark?

 

[Kenny'sID]

I take it that you have checked that the choke is fully closing and opening, and that the throttle plates are doing the same? Have you pulled the spark plug and determined that it too was ok and gets a full, consistent spark?

Yes, all those things are fine. I haven't taken it out of the house yet to try it but I did pull the carb last night and "may" have found the problem. I got the float off, then thought it funny the needle valve was still in place, so unless something odd happened I didn't notice, it appears the needle valve was not joined to the float and it wasn't properly assembled originally. The very tiny retainer that joins it to the float tab must have been underneath the tab. I can't quite picture in my mind the condition that might cause, but am thinking it might have let just enough gas into the carb to run the way it did, but hard to say.

It's a real pain to get it in and out for a trial with the steps and all so I'll wait for other suggestions or verification I may have fixed it then test it later.

Thanks for the reply.

 

[Kenny'sID]

I moved it to an outside doorway and gave it a try...no change, so I was likely wrong about the float valve and it was fine. Had it not opened, the thing provably would not even run.