max rpms 115 merc

[dcf]

New bee here,
whats the max a 1992 115 should rev, We purchased a prop that was to be identical, well its not, also when the motor is held at about 1850 to 2100 rpms (just the speed we need to pull littler kids tuben), the motor will spuder, will do this under a load only, just raising the rpms in neutral it runs fine, take off from a dead stop, runs fine, it almost sounds as if a couple cylinders will misfire.
thanks, Dean

 

[daveswaves]

Re: max rpms 115 merc

New bee here,
whats the max a 1992 115 should rev, We purchased a prop that was to be identical, well its not, also when the motor is held at about 1850 to 2100 rpms (just the speed we need to pull littler kids tuben), the motor will spuder, will do this under a load only, just raising the rpms in neutral it runs fine, take off from a dead stop, runs fine, it almost sounds as if a couple cylinders will misfire.
thanks, Dean

s

It could just need to be richened up a bit, thats just the rpm range where the mid speed carb circuits come into play, often a lean condition will be felt here. As a quick test you could turn your low speed carb screws counter clockwise 1/4 turn and try it again. The high speed jets are fixed, the low speed will be the only ajust screw. If you still have problems at this speed you may have to change to a lower pitch prop to get the rpms up when pulling the little guys.

 

[dcf]

Re: max rpms 115 merc

found my service manuel and it states the max rpms range is 4900 to 5200, my motor will rev to at least 5600 full throttle, thats too much so I'm going to look into a different prop. will try try the screws a quarter turn tomorrow. thanks daveswaves,