Small outboard motors.....again

Hi everyone,

Over the past 6 years, I have turned into an amateur small outboard mechanic. I've cleaned and tuned carbs, replaced fuel filters/lines, to say nothing about oil/gear oil/filter changes.

I've been tinkering with my Suzuki and I think I have pretty much everything working, EXCEPT that it seems to be not getting enough fuel when running WOT. I am beginning to suspect it's either:

• Fuel demand valve
• Primer bulb
• Quick disconnect on the fuel tank is not properly connected or leaking air

When running WOT, I can feel the primer bulb starting to go soft. Within 10-15 minutes, the outboards starts to stall out, and I can get it going again by pumping the primer bulb, which leads me to believe the issue is one of the 3 listed above. I'm pretty sure it's not the fuel pump, as then it would show issues even at idle. Does that make sense?

Have you checked the float height?  If the float is too low, it'll run fine on the pilot and needle jet, but as soon as the main jet is wide open, it'll deplete the bowl faster than it can refill.  It could still be the fuel pump.  The fuel pump may be filling the carb bowl quickly enough during the majority of throttle range, but cannot keep up with the main jet.

Hi Tedski,

Heh, I actually got a new carb and installed it last weekend, so the float should be good. I'm really trying to debug the lowest-cost items before I tackle the fuel pump, which is more $$$. It's a 2018 Suzuki with less than 300 hours on it. I really hope it's not the fuel pump....

BTW, it's a royal PITA to remove/adjust the float on these small outboards. That's why I had to order a new carb....cuz I damaged the old one trying to remove the float hinge pin...

Fuel tank vent is clear?

Hi mickfish,

The fuel tank I have is a newish version from West Marine, which is sealed to prevent venting. There is no vent. This is per the new EPA regulations which require sealed tanks. Hence, why you need the fuel demand valve.