1992 Mariner 4 cyl running "ODD"?

Hey guys, I have a 1992 mariner 40 hp outboard on a 16ft boat. I have a problem with the motor running smooth at half, three quater, and now full throttle. The motor runs perfect at idle and just before I start to get over plain. The motor starts to bog and sounds like the rpm is starting to drop off, and then back up even when my throttle is still in the same postiton? I just replaced my water pump and impeller, would that have anything to do with it?? Could it be an ignition problem?

Re: 1992 Mariner 4 cyl running "ODD"?

First check for adequate spark, your motor needs a hot blue arc across a 7/16 inch gap to perform reliably. As engine speed increases the ignition starts to draw electricity from the high speed windings of the stator.

Download the Ignition Troubleshooting Guide found on the Support pages of CDIElectronics. There guide will walk you thru the tests necessary to test the stator. If there is a problem the tests are well spelled out to follow and solve any ignition problem.

You may have a weak fuel supply, disconnect the fuel hose to the carbs and point it into a suitable container. Pull the lanyard so the motor will not start. Crank the motor and observe the fuel supply, you want to see a strong pulsed flow, the diameter of the hose and at least an inch out, any less start checking and replacing old hose, tank dip tube and all fittings for restrictions, and rebuild the fuel pump.