82 johnson 7.5 hp won't start

[boatwrecker10]

last time it ran it suddenly started to run sluggish. i shut it off to fish for a few hours and it never started again. i rebuilt the carb, because it didn't seem to be getting fuel. i noticed it seemed to have no compression when pulling starter rope. i removed head to inspect. pistons looked good, no holes or cracks. cylinder walls were smooth. it has spark. pistons seem to be a little loose in cylinders if you shake them. i can push pistons up and down with my finger. do i need rings? don't know what else to check on this 1982 johnson 7.5 hp.

 

[tx1961whaler]

Re: 82 johnson 7.5 hp won't start

I'd check the spark and compression before going any further. You're shooting in the dark otherwise.

 

[boatwrecker10]

Re: 82 johnson 7.5 hp won't start

checked spark by taking plug out and leaving connected to wire and pulling starter cord, and saw nice blue spark. can't start to check compression, but noticed i could spin flywheel with one finger when motor was assembled. this is my first attempt at outboard repair.

 

[tx1961whaler]

Re: 82 johnson 7.5 hp won't start

checked spark by taking plug out and leaving connected to wire and pulling starter cord, and saw nice blue spark. can't start to check compression, but noticed i could spin flywheel with one finger when motor was assembled. this is my first attempt at outboard repair.

The compression is checked without starting the engine.

 

[boatwrecker10]

Re: 82 johnson 7.5 hp won't start

sorry it to so long to get back, i had to borrow a compression tester. compression is 40-45lbs. is this good enough?

 

[JB]

Re: 82 johnson 7.5 hp won't start

That is pretty low, wrecker, but possible given that you have had the head off and probably didn't replace the head gasket or torque the head bolts.

Your statement that you can spin the flywheel with one finger is alarming. Just how "assembled" was the engine? Plugs in?

You need to take a systematic approach, rather than making random checks. You may have introduced new faults by fixing stuff (carb, cylinder head) without verifying that they are broke.

Go to Engine FAQs Forum and do "Outboard won't start". Let us know what you find.

 

[boatwrecker10]

Re: 82 johnson 7.5 hp won't start

motor was fully assembled with plugs in and i could spin the flywheel with one finger. will check starting forum next. a big Texas style thanks for the help!

 

[boatwrecker10]

Re: 82 johnson 7.5 hp won't start

waiting for new head gasket to arrive. what about slight play piston has in cylinder when i wiggle it with my finger? is this ok? what should head be torqued to?