steps of compression test

[cparkerc]

Can anyone please direct me to some instructions to test compression on a outboard? I want to at least act like i know what i'm doing!


Thanks,

Carrington

 

[iwombat]

Re: steps of compression test

1) Remove all spark plugs.
2) (somewhat optional) ground plug wires to block. (Nails or spark tester works).
3) Screw in compression gauge.
4) Crank until gauge peaks on high reading (usually about 3-5 revolutions).
5) There is no step #5.


Edit: Clarification on #2 - If you simply jump the starter manually w/o turning on the ignition you don't need to ground the plugs. Otherwise, it's recommended you ground the plugs to avoid any potential damage to the coils, or making things go FOOM from the gas spraying out the empty plug holes.

 

[cparkerc]

Re: steps of compression test

Thank you Sir, appreciate it!

Carrington

 

[yellowbelly]

Re: steps of compression test

step 5 is either you say .... shxx motors bad or... everything's a ok

 

[mhg]

Re: steps of compression test

have the throttle wide open
M.

 

[flatheadlakemonster]

Re: steps of compression test

how about steps for a hand started outboard? Same thing, but pull the handle instead of keying the starter?

 

[flatheadlakemonster]

Re: steps of compression test

How about on a hand started motor? Same thing except pull the handle rather than keying the starter?

 

[F_R]

Re: steps of compression test

See step 4.

 

[flatheadlakemonster]

Re: steps of compression test

I think my Step#5 was

everything's a ok

I got between 100 and 105psi on both jugs, this is good, no?

 

[freddyray21]

Re: steps of compression test

have the throttle wide open
M.

doesn't matter one way or the other.

 

[F_R]

Re: steps of compression test

I think my Step#5 was



I got between 100 and 105psi on both jugs, this is good, no?

Sounds good to me. You are talking about the Evinrude 18, right?

 

[flatheadlakemonster]

Re: steps of compression test

Yup, it is a Fastwin 18. And getting more exctied about it by the day.....what a dork I am!

 

[asdasc]

Re: steps of compression test

You are my kinda dork though! You will fit in well here.

My first was also a Johnson 18hp from 1959. Almost identical motor to yours. I was the same way, couldn't sleep because there was so much to learn and see and take apart and figure out. When that thing fired up the first time...what a rush. Once the carb was properly adjusted, it would idle so smooth you wouldn't beleive it.

Keep asking questions, I did, and everything will work out great. Now I have no fear of taking them apart and putting them together and they so far have worked everytime.

I am nogotiating now for a 40hp Johnson and can't wait to take it apart. I did a bunch of threads when I did mine with lots of pictures which you may find interesting.

Good luck and keep us posted!

 

[flatheadlakemonster]

Re: steps of compression test

Thanks for the encouragement! I will look up your thread here soon. I think I am going to start ordering parts this weekend. I have already found a tank to eventually run it in.