Mercury 200 20hp wont start

[stretch8668]

I just picked up an aluminum jon boat last weekend and guy said the motor runs and was gone thru last year. I put it in a bucket and its a no go heres what i know from messing with it today. Theres no gas going to carb as i disconnected line to carb and squeezed primer. It has spark but i think its to weak cause i put gas on plugs and it still didnt fire. Im hopefully gonna clean up points and clean the carb but can i take fuel pump off to check for a blockage. Another thing i noticed is i can turn gear selector forwards from nuetral but cant turn it backwards.

 

[flyingscott]

What year and serial #

 

[stretch8668]

No idea on either but by looking at pics ive seen im guessing late 60 early 70 its has the thunderbolt ignition

 

[merc850]

Don't shift into reverse without the motor running

 

[stretch8668]

Ok thanks for the heads up probably why it wont go back

 

[flyingscott]

Need the serial#. Thunderbolt covers several different versions of mercury ignition system. And they are not the same

 

[stretch8668]

Serial number is 2151379

 

[merc850]

The only Thunderbolt motor I know of was the 1950-4 40hp. 4 cyl.

 

[stretch8668]

It says thunderbolt ignition on front of motor under cowl

 

[stretch8668]

After some searching i found out its a 1967 is this correct and can i take fuel pump off to inspect diaphragm and a blockage

 

[flyingscott]

The thunderbolt designation for the ignition systems was used from the 60s to the late 70s possibly early 80s. Yes you can take the fuel pump apart to look at it to check the diaphragm.

 

[stretch8668]

Got good news i got it to run for lil bit but wont stay idling is idle screw on top and how many turns out. Are there any other adjust ment screws on it.

 

[flyingscott]

1.5 turns out on the low speed jet on the carb should get it running and will have to adjust from there as the motor gets warm.

 

[stretch8668]

Think it needs a fuel pump cause it wont stay running unless squeezing bulb. Cept when i had it apart it looked fine any way of telling.

 

[stretch8668]

Finaly got boat runnin good i think the idle mixture hole was clogged. I disconnected fuel line to carb and pulled it over and saw gas squirt out. Then i took idle needle out and sprayed carb cleaber in it. Is there suppose to be an o ring at end of idle mix screw cause i noticed theres a groove like theres suppose to be one

 

[merc850]

Doubt it's for an Oring probably from closing the screw in too hard.

 

[stretch8668]

Its on the head end of screw the needle end looked fine and didnt look like it had been over tightened.

 

[stretch8668]

Finaly was able to take boat out today but in order for it to start i had to have choke open and turn throttle to open butterfly for it to start. Once started i had to let it idle in nuetral while holding throttle open a lil then put it in gear and very slowly give it gas as it picked up speed. I also dont feel as though it was going in upper rpms as it didnt get on plane. The boat is a 14' blue star aluminum with 3 adults and a 4 year. I just feel as though itd be faster then what it is and i think its loading up on gas. I know float isnt stuck as i already took carb apart and valves in fuel pump move freely also. When i did idle mixture screw i set it 1.5 out how do i adjust it properly

 

[stretch8668]

I also noticed when i got it home i forgot to open vent on tank but i dont know if thatll cause it

 

[stretch8668]

Took it out agin today and it ran better but still not into the upper rpms. This time i made sure vent was open