Help engine coughs

[Gale63-25hp]

Help engine coughs. I need some help, my 1963 Gale 25hp starts and idles fine. Has good take off I can be running 6mph to 23 mph at a steady speed , then engine kinda coughs or cuts out for 1 second. It kinda jerks the boat. I've ran out of ideas. My dads 1972 20hp evinrude is doing the same thing.

 

[Vintage Iron]

Does the cutting out occur at the same time, every time? (Like every 4 minutes, etc.) If it's irregular, take a look at your fuel tank and your fuel filter. If there's something in your fuel supply that's getting sucked up around the filter element, this might be cutting of the flow and causing the engine to lose speed. As the rpm's drop, the suction drops and the contaminant falls away. Engine gets a full supply of fuel and you're back in a business. For a while...

Another possibility is that you've got a coil breaking down and cutting out. That one is tougher to troubleshoot, because you've gotta catch an intermittent electrical problem in the act to see what's really happening.

 

[Gale63-25hp]

It happens about every 20-30 seconds

 

[Vintage Iron]

Because the timing of the occurrence is so consistent, I'd look at fuel supply. Check your filter element for crud and clogging. Check your pump for consistent output and then check your fuel lines for weathering, cracks and wet spots (leaks). Another way to check for adequate pump output is to run the engine til it hiccups. Immediately shut off the ignition. With the engine stopped, drain the carb bowl and check fuel quantity and quality. What you see will help determine if you've got supply side problems or if there's a carb issue.

 

[F_R]

Tell ya what, I'll bet it isn't coughing. It is coming out of gear, rotating 1/2 revolution and slamming back into gear. Most people describe it as feeling as though you ran over a log----or here in Florida, a gator.

Very common, it is caused by a worn out clutch dog in the lower unit. To confirm, rest your hand on the gearshift lever to see if it jumps when the problem occurs.