i have a 1972 Johnson 50 hp 50ESL72C Outboard Motor,that i need some help with .

i have a few questions about this engine so i hope maybe someone will know and be able to give me a hand . ok first thing we just rebuiltthe carbs and it doesnt want to start unless i hold the linkage down to open plate, fast idle doesnt seem to do a thing ,started with 1 1/2 turns each mixture screw and have gotton to over 2 1/2 turns out and back in with the mixture and still wont start on its own without helping it and for sure no idle. does someone know the correct timing specs ,are they betwen 18 and 22 deg or am i off? and what is the correct idle mixture setting. also wondered if the shift/throddle cable being worn and case cracked will cause the engine not to run and idle . the boat when running before we did carbs worked ok and did idle started great . we had an issue with the engine not getting up much past 3000 rpm at full out on the lake and stood on its tail and bogged when i had more then just me in the boat . did well with just one person and i thought prop but didnt want to change prop until engine was getting the rignt power to it . compression check today was not real good top cyl was almost 150 and bottom about 110 so way over 10 % .then a guy told me that pouring some brake fluid in the spark plug holes and let sit overnight it will fix compression at least for a while ? any help will be great ! i am new to outboards but i want and need to learn ! thanks so much for any help

These motors have a history.----With those compression values your next step is to remove the cylinder head.-----Inspect piston, head gasket and cylinder wall.----------There is no amount of adjusting that will make this motor run properly with that compression being bad.

ty i was hoping you did not say that lol, was hoping not to have to do that yet but i guess i have to . any help with the timing specs and the idle screw settings and the right gap for the plugs ? i need to buy a book for it but dont have the cash atm ,things are tight and the boat doesnt rank high with the mrs as far as spending money atm .But i want to go fishing ! lol and thanks for the feedback racerone ! you will most likely be hearing more from me as i get into this motor and being a rookie i will need all the help i can get ! thanks bud

Simply put the timing on these motors is fixed at the factory and rarely needs to be adjusted.----A sheared flywheel key does throw the timing out.----Best to have a proper manual handy to see how timing is checked / adjusted.

150 psi on the top cylinder? That seems awful high. I've got the same motor, and it's about 110 - 115 psi on both. You say it won't start unless you hold the throttle plates open. Sure you aren't holding the choke closed? Is the choke working? And there is no shift cable on that motor...it's electric shift. So if your throttle cable isn't working right, and the fast idle isn't working, it will be hard to start. Buy a manual. A factory one if possible.

Won't rev past 3000 rpm on the lake. Bogs down, won't plane with more than one person. Sounds like it is way overpropped. Too much pitch. I don't know what boat you have it on, mine is on a heavy 15 foot fiberglass runabout. I run a 17" pitch prop with just me, a 15" with more people or for skiing. Runs right around 5000 rpm with just me, at about 30 mph.

Idle mixture screws....what were they at before you did the carbs? I have no idea where mine are set, I've never touched them or the carbs, and I've had the boat/motor for over 10 years.