Auction purchase 1973 18hp evinrude issues

[Kawaiikeno]

I picked up a nonrunning 1973 18hp evinrude cheap at auction after cleaning the carb, replacing the water pump changing the oil in the lower end, new spark plugs, replacing one ignition coil and the pickup coil resetting the points and changing the condensers I now have a running motor.
Only thing that doesn't seen right is it wants the low speed needle jet open between 3 and 4 turns to get rid of the coughing.
Compression is good at low 120's on both cylinders, timing on both cylinders falls with in the two marks when running as checked with a timing light.
I've sprayed evinrude engine tuner around all gaskets on the intake side with no change noticed.
As soon as I get the rest of the parts to convert it to electric start I'll take it to the lake for a real test.
Question Does it sound like maybe I should be replacing the crank seals?
Thanks Mike

 

[racerone]

I have seen the carbon seal on the bottom cracked.----Even found that seal assembled wrong on one parts only motor.

 

[kbait]

LS needle should be 1 to 1.25 turns open from seated. Likely some debris under the larger compression plug on top of carb. If you didn’t remove/clean/replace, do so. If you did clean that chamber/replace plug, something likely came through to plug one port inside..
Did you replace fuel line from pump to carb(5/32”)? If original - and had ethanol fuel sitting inside, the inside of hose may be deteriorating and sloughing off to gum up carb.
One way to clear that chamber w/o pulling that disc.. Drain carb bowl, remove LS needle, and blow compressed air through LS port. Usually this will force any crud through ports into carb throat. Now test run and hopefully you are setting it at about 1 turn open.. Good luck!

 

[Kawaiikeno]

I've cleaned the carb 3 times the last time I blew a lot of cleaner and compressed air through the low speed circuit.
I do have a 1965 18hp carb I can try on it, although not the same if it requires the same 3-4 turns out it will confirm if there is an vacuum leak before the carb
Thanks for the replies
Mike

 

[racerone]

Carburetor " problems " usually turn out to be something else.----Good trouble shooting will find what the problem is.

 

[Kawaiikeno]

Yea I'm thinking it's an air leak somewhere and I'm ok with that.
Half the fun is taking a rough looking non running old motor and bringing it back to life.
The only thing I haven't gone through yet is the power head and I'll have less than $300 into it and that's adding electric start taken from a $50. parts motor.
I will say this hobby is addicting so far I've done a
1955 7.5 Evinrude
1958 7.5 Evinrude
1972 4hp Evinrude
1973 18hp Evinrude (In progress)
1979 15hp Evinrude
1981 7.5hp Honda 4 stroke
1981 25hp Mercury (So far this one is beating me)
Mike