View Full Version : Stalls on a Yamaha IO 30 litre 4 cyl 1993

MIton Apollo
06-10-2007, 05:35 PM
"My engine sometimes stalls when I deccelerate. Stalls sometimes when I accelerated. The idle speeds varies between 950-1100 rpm. I cleaned the fire arrestor, carb, linkage,choke. tried adjustings mixing screw, idle.
I removed the themostat 2 yrs ago since it got stuck. Could this be part of my problem. What problems can occur if the engine is running too
cool. Also added dry gas.
/ thanks"

07-04-2007, 09:16 PM
"It sounds like it could be time for a Carb Rebuild,+ a Complete Tune Up........."

08-31-2007, 10:19 PM
"I have same engine and same problems, mine does have a thermostat [new]. Engine runs good overall, however the instability in idle is annoying. Idle runs stable at one RPM, but changes to another RPM each time the engine is revved. Occassionaly stalls due to this, on decel or accel. I'm thinking its time for a carb rebuild too, since my choke butterfly is slightly sticking, but got a sneaking suspecion it will not fix problem. It may be a combination of linkages/control handle, carb/vacuum and for some reason I think timing may play a part since its so sensitive to being off-timed and it floats higher & lower around the 4deg BTDC. I need to take a day to really dig into it. Have you fixed issue with tune-up and new/rebuilt carb?"