Re: RDE-17 Johnson tuning issues

[David Stanton]

I ran your video again, and I think your problem is carb-related because you had a few seconds of smooth running before it coughed and quit. First, I’d back down to a slower idle and see if you can get it to run smooth by adjusting the idle needle. Next thing I’d try is setting the high speed needle richer in 1/8 or 1/16th turn steps. If you do this and find a spot where it doesn’t die at throttle setting somewhere above slow idle, even though it may cough, then I’d put in on a boat and further adjust the high speed needle. You will also find that changing the idle needle a bit may mean readjusting the high speed needle because quite a bit of gas is sucked through the low speed passage when running at high speeds.
I don’t think it’s reeds because it ran smooth for a few seconds.

You may also see if it stays running with the choke part way on – this also tells you the high speed knob needs to go richer.
Don’t ever expect really smooth running just above idle speed, especially with a cold motor – it’s the way all the RDs I’ve had are – you can get smooth running a bit above idle by turning the idle needle richer, but then it probably won’t slow idle good when warmed up.

Another thought – I’m wondering if your tank is getting pressurized enough to keep the carb full? Will it stay running if you keep pumping the tank primer?
Dave