compression test = 70 psi.. good? bad?

[noob_boater]

1970 johnson 20R70E. After 4-5 pulls, i got 70 psi max on each cylinder. Good? Bad? Kept pulling but wouldnt move pass 70. Wonder if this is the reason motor wont fire up.

 

[boobie]

Re: compression test = 70 psi.. good? bad?

The 70 psi should make the mtr run. Better check your spark, which should jump a 1/4 " open air gap on a spark tester. If it passes that test, squirt some premix fuel into the carb throat and see if it pops off. If it does, do the carb. Got new plugs ??

 

[noob_boater]

Re: compression test = 70 psi.. good? bad?

new plugs champion J6c. Having a hard time testing spark. Can't concentrate enough on the spark plug and pull the rope at the same time. I, do, however noticed a slight darkish burn mark on the tip of the new plugs after many pulls... BUT probably not enough spark. Gonna try it in complete darkness tomorrow..

i sprayed from premixed fuel into spark plug hole, but not into carb throat. If this fails, gonna pull the whole starter group apart. Any other methods of pulling the fly wheel off without a special tool?

 

[JB]

Re: compression test = 70 psi.. good? bad?

70 psi is fine for a rope start outboard, noob. Your trouble is elsewhere.

 

[noob_boater]

Re: compression test = 70 psi.. good? bad?

70 psi is fine for a rope start outboard, noob. Your trouble is elsewhere.

what are these hoses here for?

>>leaking

>>> No fuel when unplugged. Fuel suppose to be there?

i think i am leaning towards no sparks or clogged carb down the path somewhere

 

[boobie]

Re: compression test = 70 psi.. good? bad?

You can buy an open air gap spark tester at most parts houses for around $8.00. Checking the spark with the plugs will tell you nothing.

 

[noob_boater]

Re: compression test = 70 psi.. good? bad?

i made an air gap tester like this, looks just like the ones at the auto parts stores.

tested in total darkness and didnt see any spark at all, so i think there is NO spark. sprayed fuel into spark plug holes, no fire. Tried spraying into carb throat, no fire, still. Sprayed spark plugs with fuel, no fire again..

how the hell do i remove the flywheel?

 

[nwcove]

Re: compression test = 70 psi.. good? bad?

you need a harmonic balancer puller , but try moving the nails closer to see if spark will jump at any distance.

 

[noob_boater]

Re: compression test = 70 psi.. good? bad?

if i dont have a puller, any other ways to do it? what's holding the flywheel on so tight anyway?

 

[nwcove]

Re: compression test = 70 psi.. good? bad?

if i dont have a puller, any other ways to do it? what's holding the flywheel on so tight anyway?

no other way to remove it and be able to re-use it, its a cheap tool. the tapered shaft, and 40+ years are whats holding it on. ( you can actually just set a flywheel on the tapered shaft and not be able to lift it off by hand 5 mins later!),

 

[BonairII]

Re: compression test = 70 psi.. good? bad?

if i dont have a puller, any other ways to do it? what's holding the flywheel on so tight anyway?

http://www.harborfreight.com/46-piece-bolt-puller-set-37824.html

 

[noob_boater]

Re: compression test = 70 psi.. good? bad?

Using a 2x4 wood, i place it under flywheel and whacked it a few times and it popped out, but look like this little piece broke off. AM i fugged!!?? with wheel puller, i would assume that piece would've still broken off..no? yeh?

Are both suppose to be touching?

 

[nwcove]

Re: compression test = 70 psi.. good? bad?

appears to be a sheared flywheel key...cheap part. points open and closed are what delivers spark to the plugs....with the sheared key it wont happen at the right time. ( points open= spark, points closed= waiting to open to deliver spark....i know it seems backwards, but thats the deal. get a new flywheel key )

 

[BonairII]

Re: compression test = 70 psi.. good? bad?

Sorry to be the "arse" here, but what possessed you to get a 2X4 and whack the flywheel off?? Being cheap(not wanting to buy the proper tools) will cost you more money/aggravation than the tools cost.

The flywheel will need to be torqued down to a specific value when installed....are you planning on using a torque wrench or just "winging it"?

 

[noob_boater]

Re: compression test = 70 psi.. good? bad?

seems like this flywheel has been taken apart before by looking at screws. not sure if the flywheel key was already broken or i broke it. anyways. i adjusted the screw and got both parts touching. Before no sparks, this time i get SPARK, but only on the lower one . so are you saying i should adjust the screw and leave the other open as it was before?

 

[noob_boater]

Re: compression test = 70 psi.. good? bad?

Sorry to be the "arse" here, but what possessed you to get a 2X4 and whack the flywheel off?? Being cheap(not wanting to buy the proper tools) will cost you more money/aggravation than the tools cost.

The flywheel will need to be torqued down to a specific value when installed....are you planning on using a torque wrench or just "winging it"?

i have a torque wrench.. seems like the flywheel came off rather easy though. looked like it was removed before.. i only whacked it like 2 times on each side and it wasn't hard whacks too. i was surprised to see it popped off..

 

[tx1961whaler]

Re: compression test = 70 psi.. good? bad?

The points open and close as the flywheel turns around. Yes one set is supposed to be open and one is closed.
The broken thing is the flywheel key. That's why you need to use a 3-bolt puller to get the flywheel off properly.
You can normally borrow one for free from the parts store.

7/16" is very optimistic for the spark gap. 1/4" is good for the universal magneto system.

 

[noob_boater]

Re: compression test = 70 psi.. good? bad?

thanks guys. i'm slowly learning.. just placed an order for 2 flywheel keys on boatsDOTnet. i am wondering if the flywheel key was always broken and that's why it stopped working when a few hours before, it was working just fine. if this doesn't solve my problem, time to buy new motor...

will this motor operate on one cyclinder?

 

[boobie]

Re: compression test = 70 psi.. good? bad?

As Tex said, 1/4 " gap is the proper gap for testing that ign system. Nice job on the spark tester.

 

[tx1961whaler]

Re: compression test = 70 psi.. good? bad?

thanks guys. i'm slowly learning.. just placed an order for 2 flywheel keys on boatsDOTnet. i am wondering if the flywheel key was always broken and that's why it stopped working when a few hours before, it was working just fine. if this doesn't solve my problem, time to buy new motor...

will this motor operate on one cyclinder?

Less than 24 hours and you're ready to give up?
Yes, a sheared flywheel key will cause it to quit working. The timing will be completely off with a broken key.
The last guy maybe didn't torque it down, which is also why it was easy to pop the flywheel off.
The motor will operate on one cylinder.