Engine Troubleshooting Ideas

[49dimes]

Factory recommended.....STARTING POINT!............Terry!

 

[Bunky.F.Knuckle]

All,

I'm helping a new guy at the field tune his RCGF engine.

We start it up, lean the High needle for Max RPMs and then go to idle and start leaning the Low needle.

The problem is that as we lean the Low, the idle RPMs rise to 2500-300. We can see the carb arm is closed all the way. If we richen the low, a bunch, the RPMs come down, but isn't that just because we are dumping in too much fuel, esentially drowning the engine?

What would be causing the engine to idle so high?

The carb butterfly does have a hole in it.

That combined with other air leaks around the gaskets?

Ideas appreciated.

P.S. - I KNOW it's a crappy motor, wouldn't buy one myself, but I'm trying to help out a newbie.



BJ Swope

Actually, we at TDRC just started to sell RCGF. It looks alot like a DLE, but they have CNC cases. As others have said, tune the L then tune the H.

We have a 120 coming, and it looks promising. If it equates to EME 120 power, it will be a good engine.

 

[Naughty Monkey]

We can see the carb arm is closed all the way

So are you looking at the arm on the outside of the carb, or have you looked in the throat of the carb? My edumacated guess is that the throttle plate is not actually closing all the way. Most of these carbs either have an idle stop screw or a tab on the throttle arm that hits a stop on the carb body. Either remove the screw or bend, cut, hack the tab off the arm. When you say there is a hole in the throttle plate, I suppose it is at the edge. Unless someone has messed with it, its normal and should be by the jets, the little holes in the carb throat and helps the air flow across the jet. If there is a gasket leak , it is going to have the opposite effect and the engine will idle low, be hard to start and need more fuel as you have air entering the engine that has bypassed the carb and isn't getting fuel missed into it.
Hope you get it figured out and get some karma for helping out the new guy.

 

[Naughty Monkey]

View attachment 46421



BJ Swope

I thought I was the reason for that one.