Hello,
I have a 90 HP Mercury SportJet in my Nautica Rib that won't go over 3K rpm without bogging or stalling. I pulled the plugs and the top two look normal (light oil/gas mix, not dripping or fouled) and the bottom plug looks brand new and dry, like it's fresh out of the box. The plugs are new NGK B9HS-10's.
The boat is setup to run on premix (40:1) and has one carb feeding all three jugs. It runs beautifully below 3K rpm -- fires right up, idles smoothly. It just won't kick into high gear.
I plan to change the plug wires (as soon as I can find some) and change the fuel filter. I thought I'd also try squeezing the primer bulb while it's running to rule out the fuel pump.
Here are my questions:
1. If the #3 plug is dry and looks new, is it starving for fuel (and therefore lubricant) and if so, is it at risk for a piston meltdown? If so, I won't try anything else until a mechanic looks at it.
2. Could it instead indicate a lack of spark in #3? I noticed that there seem to be issues with triggers/stators on these.
Any assistance you could provide would be great. Thanks!
I have a 90 HP Mercury SportJet in my Nautica Rib that won't go over 3K rpm without bogging or stalling. I pulled the plugs and the top two look normal (light oil/gas mix, not dripping or fouled) and the bottom plug looks brand new and dry, like it's fresh out of the box. The plugs are new NGK B9HS-10's.
The boat is setup to run on premix (40:1) and has one carb feeding all three jugs. It runs beautifully below 3K rpm -- fires right up, idles smoothly. It just won't kick into high gear.
I plan to change the plug wires (as soon as I can find some) and change the fuel filter. I thought I'd also try squeezing the primer bulb while it's running to rule out the fuel pump.
Here are my questions:
1. If the #3 plug is dry and looks new, is it starving for fuel (and therefore lubricant) and if so, is it at risk for a piston meltdown? If so, I won't try anything else until a mechanic looks at it.
2. Could it instead indicate a lack of spark in #3? I noticed that there seem to be issues with triggers/stators on these.
Any assistance you could provide would be great. Thanks!