Repairs and test results

[muskyjim]

I finally made the repairs and upgrades that I have been asking all the questions about.
First off: My OB is a 1979 70hp Johnson, 6 amp unregulated system.
I installed a new rectifier, a tachometer, new plugs and tested cylinder compression in all 3 cylinders.
The results: the motor idles at 1000 rpms.
Cylinder compression is 120 at all cylinders.
I would like to hear back from the forum on how this sounds. Do I have any worries, do I need to run more tests and what would they be?
The installation of the tach and the rectifier went so well I'm almost worried.
Jim

 

[iwombat]

Re: Repairs and test results

More on your idle . . .

Is that under load (in water) or no load (muffs)?

In gear, or in neutral?

1000rpm is high. But real high, or just a little high depends on those factors.

 

[muskyjim]

Re: Repairs and test results

Sorry about that.
It was no load. (Water muffs).
I don't know if it makes any difference, but the carbs were not covered either.
I took the piece off that covers the carbs so that I could spray some deep creep in before I changed plugs and did my testing.

 

[jtexas]

Re: Repairs and test results

I have the blue version of that motor...compression 119, 119, 120, unchanged over the last 4 years...treat her right she'll never let ya down.

 

[iwombat]

Re: Repairs and test results

Cowling and covers off makes a difference too.
Given all those factors, I'll bet is settles down to around 600-700rpm in gear and in the water. That's right where it should eventually land.

 

[jtexas]

Re: Repairs and test results

yah it'll scream & fly with the airbox off, make you want to run her that way all the time....but don't....[sigh]....

 

[muskyjim]

Re: Repairs and test results

I never planned on running without the carb cover. I took it off before my compression test so that I could spray some Deep Creep into the carbs. I also had to make a new gasket for the cover. I'm confident that now that it's all put back together it'll run great.

 

[iwombat]

Re: Repairs and test results

Just for future reference, if you look on the side of the airbox there's a small hole for "fogging". You can inject your deep creep in there via the straw.