Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: tuning low speed jets on carbs
Posted by brooks89 on 06/09/10 - 11:53 AM
#1
I've got a 2000 70HP 2 Cycle 3 Cylinder Johnson Outboard. Recently I've been experiencing the motor stalling out idle speed in forward and reverse. I suspect I may need to adjust the low speed jets. The boat idles fine at 1000 RPM when in neutral but drops to 800 RPM when the prop is engaged and eventually dies out unless I go back to neutral from reverse or throttle through it in forward. It's running like a champ at high speed.
My plan was to turn the needle valves in gently counting turns see where they are at now, then unscrew the valves, use some carb cleaner in the orifices and reset the valves.
Can anyone give me some advice here? Carburetors are like black magic to me. Any thoughts as to whether the current low speed mixture might be too lean or too rich?
Posted by CES on 06/09/10 - 12:12 PM
#2
I wouldn't adjust your jets as much as I'd clean the carb jets with carb cleaner as you have stated. It sounds to me that your carbs are gummed up.
Posted by John Fyke on 06/09/10 - 12:42 PM
#3
I would never mess with carburator factory adjustments unless the carb was totally rebuilt. Clean them. It's not that difficult and see what you have.
Posted by awayland on 06/09/10 - 12:57 PM
#4
Try Putting a heavy dose of seafoam through the fuel system. Advanced auto parts sells it.
Posted by sosmerc on 06/20/10 - 6:56 PM
#5
With age, tolerances do change and this can affect your idle quality. Clean fuel system is a must as has already been mentioned, but it may also be time for an experienced technician to do what we refer to as a "synch and Link" procedure. This is a "by the book" tuneup procedure whereby the linkage is adjusted and set to specific factory specs. Verification of proper idle temp is also important....you may have a thermostat issue.
Posted by DWinter on 06/21/10 - 7:27 AM
#6
Most likely in the early stages of ethanol induced problems. Like the guys above said, it's time for a cleaning.
Posted by brooks89 on 06/21/10 - 8:00 AM
#7
Thanks for the input Men! I use premium gas and fuel additives on regular basis and my carbs look clean as whistles. I gave the motor an extra slug of Seafoam but I suspect the problem (more of annoyance really) is not treatable chemically.
I did recently spend an hour with the cowling off looking around at the throttle linkages, not really sure why, but thinking some sort of adjustment might be needed. There wasn't anything obviously worn or out of place. So SOSmerc could be on to something...