My sons recently acquired a Suzuki DT-65. It is in overall good shape with compression readings of and even 130 in all three cylinders. We changed the water pump, and sealed the lower unit. It fired right up and ran in the tank. Once on the back of the boat it bogged under load. This is intermittant and took quiet a bit of throttle work to get the boat up on plane. I bought an OEM Suzuki repair manual and three carb kits. Once the carbs were rebuilt we set everything to spec. The problem persists. Here is what we have.
Fuel system has been cleaned thoroughly, carbs disassembled and rebuilt with new kits, hoses, primer and connectors replaced with new. New diaphram in fuel pump.
Three new spark plugs properly gaped. All three show good spark in all ranges.
The trolling switch functions according to spec.
The timing advances at start up and drops back after 15 seconds according to spec.
Under load the timing advances to just below mid throttle then become irratic while the engine bogs.
With boat strapped to trailer and motor in water check of timing advance with timing light show timing steady advance to just below mid range then timing got irratic.
The throttle advance/idle switch shows continuity according to specs.
With the throttle advance/idle switch removed form the motor it continuity as the switch is advanced with a screw driver until just below mid range. Then the continuity meter's steady whistle starts to chirp and as the switch is rotated to WOT the continuity meter whistles steadily showing continuity.
I am leaning to a faulty throttle advance/idle switch.
Any thoughts?
Thanks
Tony Mig.
Fuel system has been cleaned thoroughly, carbs disassembled and rebuilt with new kits, hoses, primer and connectors replaced with new. New diaphram in fuel pump.
Three new spark plugs properly gaped. All three show good spark in all ranges.
The trolling switch functions according to spec.
The timing advances at start up and drops back after 15 seconds according to spec.
Under load the timing advances to just below mid throttle then become irratic while the engine bogs.
With boat strapped to trailer and motor in water check of timing advance with timing light show timing steady advance to just below mid range then timing got irratic.
The throttle advance/idle switch shows continuity according to specs.
With the throttle advance/idle switch removed form the motor it continuity as the switch is advanced with a screw driver until just below mid range. Then the continuity meter's steady whistle starts to chirp and as the switch is rotated to WOT the continuity meter whistles steadily showing continuity.
I am leaning to a faulty throttle advance/idle switch.
Any thoughts?
Thanks
Tony Mig.