1969 9.5 Evinrude Sportwin - Low Speed Missing

[Grandpa7]

I bought this motor from a neighbor knowing it would not run without squeezing the primer bulb. Thought it would be a simple fix. Then it wouldn't even start - neighbor moved to Florida. Got it to start on 1st pull, runs like a top at speed……misses, sputters, coughs, and dies at trolling speeds. No amount of Low Speed Adjusting will cure it.

What I've done so far:
1. Rebuilt fuel pump (OEM overhaul kit)
2. Rebuilt carb (OEM overhaul kit)
3. New plugs
4. New gas tank & all hoses
5. All tests with cover OFF (eliminating exhaust) in barrel and on boat
6. Coils, condensers, and points appear new
7. Set points per spec. 0.020. Lightly sanded
8. Runs on either cylinder with only slight drop in RPMs
9. Low speed orifices (3 in carb throat) open
10. Low speed adjust set per spec (3/4 turn open) and adjusted while running thru range.

Runs at speed perfectly. Starts on 1st pull. Hesitation when going from idle to full throttle. Misses once every 3 seconds at idle like clockwork.

Two things on the carb give me pause.
1. There is a pin sticking out of a hole in the body of the carb above the low speed adjust screw behind the smaller Core Plug. (See attached photo) Doesn't look right.

2. I could not remove the Calibration pocket Filler Plug (Item 47) located behind the larger Core Plug.

This one really has me stumped? Any suggestions?

Grandpa Bill in Grand Rapids, Michigan

[steelespike]

Sure sounds like a lean sneeze.I've heard a bad crank seal can cause
idle problems.I think it might also cause hard starting.
You might truy raising the float level a little.The blowup in my aftermarket manual doesn't show show any pin.The pin looks like it droops a little Perhaps it has vibrated out of the hole where it belongs.

[Grandpa7]

Sure sounds like a lean sneeze.I've heard a bad crank seal can cause
idle problems.I think it might also cause hard starting.
You might truy raising the float level a little.The blowup in my aftermarket manual doesn't show show any pin.The pin looks like it droops a little Perhaps it has vibrated out of the hole where it belongs.

What is a "lean sneeze"? I'll raise the float first thing tomorrow. That pin is solidly locked into the hole. Can't budge it with vise-grips. I suspect that somewhere in the past a shade-tree mechanic like myself removed a shot plug from the carb and replaced it with the pin.

[Rick.]

Try opening (counter clockwise) the slow speed needle 1/8 turn at a time and see if the miss (actually a lean sneeze) goes away. No idea about the pin. Best of luck. Rick.

[kbait]

If you blow air through the low speed needle hole, air should come out 2 places. Out of the holes in carb throat and out from the bottom of the bowl, where the low speed circuit gets it's fuel supply. Fuel is metered by the needle on its path from bowl to carb throat. If these passages are clear, it should idle nicely once the needle is adjusted. If it doesn't, inspect spark closely w/spark tester. You want a 1/4" blue bolt on both sides. If one's weak, it can give you the symptoms described.. Good luck!

[blimp]

I had this problem with my 30hp 1988. Get yourself a manual and do the link n sync, mine went from sneezing and sometimes stalling to purring like a kitten at idle. Linkage had become mis-adjusted and timing was too retarded at idle.