1966 Evinrude 100 low speed stutter

[inthedirtagain]

I've had the boat for only 2wks now, and have had it out about 5-6 times. Today, something new happened. After we had been tubing and skiing for a few hours, the motor developed a low speed stutter and would die when trying to throttle up. It almost acted as if it were loading up. I leaned out the low-speed dial on the carbs, but it didn't help. Once we had a little speed to it, we were fine and the boat was able to run out fine. What we would do to keep the stutter from stalling the motor was to flick the electric choke right as we were accelerating. This did the trick everytime, and we were able to keep skiing for several more hours. I thought that maybe I got the mixture wrong in the tank, so I switched to a different tank. No change. Last Thursday, I ran SeaFaom through both tanks and didn't have any issues with running. The problem only developed mid-day for us today. Your thoughts?

 

[BonairII]

Re: 1966 Evinrude 100 low speed stutter

Your carb prob needs a good cleaning. Idle circuits and low speed jets are probably getting clogged up.

 

[Evinrude Boater]

Re: 1966 Evinrude 100 low speed stutter

Agreed, the fact that you're choking it indicates a lack of fuel on acceleration so closing the choke flap reduces the air allowing it to run better. It doesn't take much to clog an orifice in the carbs.

 

[inthedirtagain]

Re: 1966 Evinrude 100 low speed stutter

that's what I get for running Sea Foam.

 

[inthedirtagain]

Re: 1966 Evinrude 100 low speed stutter

Don't know if it helps at all, but on this motor, all 4 carbs have the low-speed circuit linked together. I fired up the motor in a garbage can and once the motor was warm, it started to sputtering at idle again. I had previously adjusted the low-speed needles one notch leaner because it was acting like it was loading up. This time, I adjusted the circuit richer and the idle instantly improved. It also increased the idle speed about 200rpm. I lowered the idle at the throttle arm, so its sitting at roughly 800rpm now. There doesn't appear to be a bog or stutter anymore, as well. Smokes a little more now until I rev it up and blow it out. Does this still sound like a partially clogged low-speed circuit?