As the title states, I'm working on a 1972 Evinrude 18hp outboard. New points, condensers, plugs, and a new flywheel key after a torque mishap. We took the boat out (1967 Richline 14') and after putting around for a bit decided to open the motor up and see what happens. It comes up in RPM pretty well, but after a second or so at the top, seems to fall about 3-400 (by ear) RPM. Bring the throttle down and back up and it does the same thing. I'm pretty sure it's a fueling issue as pulling the choke while it's up top gives back some of the RPMs. Another possible clue is that the low speed adjustment only likes to be backed out 1/2 a turn from soft stop and it's extremely touchy. IIRC, it should be closer to 1 1/2 turns.
Things that I know:
1) Great spark on both cylinders
2) Timing is as correct as I can make it. I had to fiddle with the points a bit to get them to open to .020 and start opening at the right point. I have a timing tool from Richard for the motor.
3) Closing the choke seems to help it run a bit better up top
4) Carb has new gasket, float, needle, etc... high speed jet looked clean and clear.
What I don't know:
1) Is there more inside these carbs that controls fuel flow up top than just the high speed jet?
2) When I pulled the carb apart, there was what appeared to be a rubber grommet/ring around the base of the high speed jet that wasn't in the kit. What function does that grommet perform? It appears to just sit in the crevice around the jet and doesn't block anything. I'm wondering if it doesn't have something to do with fuel flow/pressure.
I'm going to pull the carb back off and drop it in my ultrasonic cleaner to make sure there isn't any debris or clogging that I missed. Is there anything else I should be checking for?
Things that I know:
1) Great spark on both cylinders
2) Timing is as correct as I can make it. I had to fiddle with the points a bit to get them to open to .020 and start opening at the right point. I have a timing tool from Richard for the motor.
3) Closing the choke seems to help it run a bit better up top
4) Carb has new gasket, float, needle, etc... high speed jet looked clean and clear.
What I don't know:
1) Is there more inside these carbs that controls fuel flow up top than just the high speed jet?
2) When I pulled the carb apart, there was what appeared to be a rubber grommet/ring around the base of the high speed jet that wasn't in the kit. What function does that grommet perform? It appears to just sit in the crevice around the jet and doesn't block anything. I'm wondering if it doesn't have something to do with fuel flow/pressure.
I'm going to pull the carb back off and drop it in my ultrasonic cleaner to make sure there isn't any debris or clogging that I missed. Is there anything else I should be checking for?
