Just can not figure it out

That old Mercury

Petty Officer 2nd Class
Joined
Oct 12, 2023
Messages
143
It is a new motor to me I will do all the checks that you all suggested and I will let you know the results thank you for all of your help stayed tuned
I just found out i have the exact same issue but with a 1984 150mercury.
I have some parts ordered for mine, hopefully by the weekend i will let you know what solved my problem or maybe what you find out i will try.

Good Luck
 

stresspoint

Lieutenant Junior Grade
Joined
Sep 19, 2022
Messages
1,045
OP , most older 2 smokes can be a bit of a PIA to cold start , ' in general " if you find a procedure that gets the motor to fire up and high idle with a few seconds or less of cranking you are in the ball park.
my older Merk procedure from memory was:
prime ball till hard > most important.
push key / choke in > crank till a sputter > shift high idle lever full > crank till start > slowly lower fast idle > warm up for a few min before attempting to use gears.
this procedure was how i used to set most older 2 smoke motors , Merks ,Johnnos and Rudes .are much the like when trying to get cold start set up .
the othe problem i used to face was people tinkering with screws and stuff .
most times the motors would start fine but under acceleration or high RPM they would be pigs..

FWIW to those that condescend , i stopped working , playing on old 2 smokes 20 or more years ago to move on to more complex marine engines, so lots has been forgotten.
 
Last edited:

That old Mercury

Petty Officer 2nd Class
Joined
Oct 12, 2023
Messages
143
It is a new motor to me I will do all the checks that you all suggested and I will let you know the results thank you for all of your help stayed tuned

frog man 63​

This may be a long message so if you want to skip through untill you see the 5 capital T
I replied that we had the same problem but different size motors and year models and i had ordered parts for mine and that i would let you know what i found out and maybe it would help you after you checked everything reccomended by the Great people here.
If you want to you can have my post deleted , I understand if you do.
Sympton
2-1/2 days earlier when it ran for the first time
Ran one whole can sea foam, one whole can of quick silver engine restore.
Cold start , will start with lubricated starting fluid while motor is cranking , sprayed towards carbs 5' away then cranks fine rest of the day.
Parts i installed for reliabilty, after changing tried cold start with normal cranking procedure All failed.
Stator,trigger wheel, corrected timming, two cdi boxes, complete carb rebuild, fuel pump rebuild. New gas tank , new black rubber gas line, new plugs NGK 2 were shorted internally used 2 old plugs in place
Set timming close to specs
TTTTT
I done all testing with motor submerged 2' deep in water, No muffs
This is what got mine to cold start
#1-Raise idle tab all the way up.
#2- Crank engine over and while cranking push in key for enchiner count to 3 let go of key.
#3- pull idle tab down to half way crank engine without pressing in enricher.
For my engine 150 black max this works.
May not work for you , you may have to try different idle lever positions because you have to find the air fuel ratio that makes your motor start.
Hope this may help you.
Good Luck
 

brodmann

Chief Petty Officer
Joined
Jun 17, 2008
Messages
426
If it cranks on starter fluid, it's a fuel delivery problem. Send me the year of the motor and I'll send you a diagram of your carb and let you know what to focus on in cleaning it up.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,905
First test before you start spending $$$ on parts...what is compression of cylinders?
 
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