Outboard Carb Sync ???
 

I have a 1984 Suzuki Dt-75 and Im trying to sync the carbs. I borrowed a four gauge manometer but when I hook them up all I get is a very bouncy needle. I cant get any kind of reading to try and set them. Anyone know why this would happen? Maybe bad reeds? I have the full service manual and it shows nothing about needle bounce.

Thanks Anthony

Try Scream and Fly technical section. They are outboard freaks.

fixx
 

on my snowmobile which is a 4cyl i use a 7mm dril bit,,size may vary..

I do not believe that the two stroke outboards get synchronized using a Manometer, four strokes yes. There is no previsions to hook one up as well. You must perform the sync and link procedure in order to be successful. This procedure does not include a Manometer.

What are you adjusting?
 

I don't know the Suzukis but on a two stroke in general, it needs to be under load and with the exhaust in the water to be close.
On my V-6 Johnrudes this is critical. Mine also have links between the butterfly shafts (between individual carbs) that sometimes move. This allows one carb to be fully closed and others to be partially open.
On those motors, their idle circuits are calibrated to have the butterflies closed at idle. If you have one even cracked open it is now pulling fuel through the mid range jets and will run like crap.
I start there then head to the ramp. Leave the boat on the trailer but back it in far enough to have the exhaust submerged, motor up to temp and idling in gear and then start adjusting idle screws if your motor has them. Start w/all screws set to same number of turns and then go in/out a 1/2 turn each way while listening to the motor. You want the fastest, smoothest idle.
You cannot do this at home on the hose as it will be lean (no load or back pressure) when you put it in the water and will die at dock.

It shows the procedure in the service manual and the ports are also at the base of each carb just like the book shows. But they are using a mercury filled meter to set the carbs. I only have access to vacuum gauges and that where I run into the issue.

Thanks Anthony