Tuning Help - Idling too high

[mysonisarhino]

Hello, I have a tuning issue I was hoping someone could help me with. My Rampage MT idles too fast, and the motor dies when I brake hard. I have to start the truck on a block because it takes off before I can get the body on. I’ve played with the idle and low speed screws and throttle linkage but can’t get it dialed in. It’s always ran like this since I got it years ago...I just lived with it. Other than that, the truck runs great. I’d like to get it running a little better since my son has taken interest in the hobby now. I listed my setup below. Any suggestions are appreciated—

stock 30cc motor
stock carb (high is 1 turn out / low is 1 1/8 out)
cpi tuned pipe
HPI air filter
Klotz R50 32:1

 

[Greg10757]

Have you tried the idle screw

 

[mysonisarhino]

Yes I did turn it out some to try lowering the idle, but then the motor dies too easily when applying the brakes. The idle screw is out 2 full turns currently.

 

[Greg10757]

Ok then go one turn on the idle screw in and turn the low in screw out slow about a quarter of a turn and try it it's giving it more fuel.

 

[mysonisarhino]

I turned the idle screw in 1 turn and did not notice a difference in idle speed. Turning the low speed screw out a 1/4 turn almost seemed to make it too rich. I turned the idle screw in 1 more turn which is all the way in and still didn’t notice a difference in idle speed. Just to clarify the original issue...the truck idles fast when first fired up on a cold start but then slows down and I have to goose the throttle to prevent it from stalling. It’s difficult to start after warmed up. Is that a sign of a possible air leak on the intake side?

 

[Greg10757]

That and also gas cap is Vinted

 

[mysonisarhino]

My gas cap is vented. I have new intake gaskets on order.

 

[Redredcat0223]

If the gaskets don’t cure it,I would put a whole new carb on it.That could be the whole issue and make sure the plastic block that mounts to th3 head and the carb mounts to that,I forget the name,but sometimes they crack or warp,honestly I would replace that and the carb,not expensive at all.

 

[mysonisarhino]

Thanks. I should be getting the gaskets in a couple days. I thought about replacing the carb too and will try that next if needed.

 

[owen91]

can be a leak from the gaskets??
also did you try to richen low speed needle?

 

[mysonisarhino]

I finally got my new gaskets. I got the Redcat green gaskets. I found what I thought the problem was...the gasket between the head and the plastic mounting block was almost completely gone. I replaced all 3 gaskets, but now I can't get the truck to start. I pulled and pulled and pulled. I tried with the idle screw set at 1 turn out then 2 turns out, and the low speed screw at 1 1/8 out and 1 1/2 out. I'm not sure what the issue is now. I could get the truck to start cold fairly easy before replacing the gaskets. Can someone tell me the best place to get a new stock carb and plastic mounting block?

 

[Redredcat0223]

You probably did but did you check the plug?

 

[mysonisarhino]

I didn’t check the plug because I didn’t make any changes that would have affected it. But I will check it now that you mentioned it.

 

[Redredcat0223]

Ya doesn’t matter,sometimes that stuff just goes bad,but If I couldn’t get mine started,I would check spark,fuel and air!

 

[RRXT66]

Did you check your throttle positions on your controller? It should be set close to 0

 

[mysonisarhino]

I have spark. I checked it by grounding the plug while in the wire and pull starting it. The plug was wet, so I’m getting fuel. I can check the lines tomorrow to make certain though. I did disconnect the throttle linkage at the servo arm while replacing the gaskets, but I’m sure I reconnected it the same way and did check the throttle position on the transmitter. I usually have it set at 1.

 

[Redredcat0223]

Even though it shows spark that plug still might be bad,I’ve seen it and heard a lot of people who have had that issue,usually with a dry plug and fuel lines correct,to start these engines is very simple,just pump the primer ball till it fills up,put the choke on,pull it ,usually takes 1-2 pulls and it will slightly bump off a hair now pull the choke lever back up and pull start again and now usually again 1-3 pulls and starts right up,please don’t take anything I’m writing as if I’m thinking you don't know any of this,I’ve seen so many people make a huge issue out of starting there engine when it would start right up this way,anything I’m writing is honestly just to help!

 

[mysonisarhino]

I appreciate all feedback. It has always been easy to start my truck up until I replaced the gaskets. I sprayed starter fluid down the carb and it still didn't start, so I guess maybe I could have a weak spark. I'll get another plug and try that next. Is it possible to put that plastic carb mount block on in the wrong direction? I think I remounted it the same way, but it's possible I missed something.