1972 20hp Johnson hard starting

[sbassman]

I just recently purchased a 1972 Johnson when I started the motor with the muffs connected in the driveway the motor started quick and easy and ran great. Two days later i take it to the lake and now the motor is hard to start, once started I ran the motor for about 10 or 15 min and shut it down, then tried to restart immediatly and the motor was hard to start again, is this possibly a spark plug problem, or do you think a fuel pump???? Motor once started idles and runs just fine

 

[kbait]

Re: 1972 20hp Johnson hard starting

First, unless you have an adapter, muffs don't work on that style lower unit. Read up on 'top secret files' at the top of this message board. You'll wanna check spark w/a tester, determine compression.. etc. Good luck!

 

[tashasdaddy]

Re: 1972 20hp Johnson hard starting

it may have run hot. you probably need a new impeller, if not complete water pump kit. muffs are not for those motor, leg has to be submerged, 1/2 way up.

green is exhaust relief port and tale tell, yellow exhaust, RED is water pick up intake.

 

[1946Zephyr]

Re: 1972 20hp Johnson hard starting

If this motor is hard starting, I would look over the condition of the coils. Bad coils will allow the motor to start good at home, but hard to start out on the lake. I've seen this many times. These tend to get old and cracked and a lot of times will cause hard starting. Motors like these are generally very responsive to a pull start. If you remove the hand starter assembly, you should see a small plate on top of the flywheel. This will open up a sight hole through the flywheel, so you can see the coils. Rotate the flywheel (clockwise only) and you can see both coils. Front coil is for the top cylinder and rear coil is for the bottom cylinder. Also check and make sure points are set at .020 With the sight hole above each point set, that will position the cam in the right location to set the point gap at it's correct gap.

 

[jasper60103]

Re: 1972 20hp Johnson hard starting

Also, what do your plugs look like? I was running too rich and fouled plugs made my motor hard start.

 

[sbassman]

Re: 1972 20hp Johnson hard starting

First, unless you have an adapter, muffs don't work on that style lower unit. Read up on 'top secret files' at the top of this message board. You'll wanna check spark w/a tester, determine compression.. etc. Good luck!

Acrtually it pumped water just fine with the muffs, and the motor seems to pump water just fine when its running.