1977 Johnson 70 hp

[RapidRog]

What are the settings for the Command Center? The motor runs very nice but when I slow the idle down to the point where I can shift into forward or reverse, the motor kills. A quick movement into the far position for forward also kills the motor

 

[oldcatamount]

Re: 1977 Johnson 70 hp

I've got a 50 hp that did the same thing. You may need to clean and re-build your carbs. A pair of new spark plugs will certainly help to.

 

[jtexas]

Re: 1977 Johnson 70 hp

been like this since you got the motor? how long?
Any other symptoms? cold start, warm start ok?
When it dies does it immediately restart?
What recent maintenance has been done to the motor?
Is the fuel fresh?
Tank free from water/debris?
Spark plugs -- are they Champion QL77JC4 gapped at .030, in good condition?
What's your idle RPM?
Can you get it to run full throttle? If so what's the RPM?

Not sure what "settings" you mean.

Do a compression test and spark test (not a "spark plug" test): get an inline spark tester (couple bucks at autozone), set the gap for 7/16", clip it to the engine block, attach the plug leads (one at a time) and look for a strong blue spark while cranking. If it can't jump a half-inch gap in the open air without a spark plug, it's not firing in the hole under heat & compression.

Report your results.

 

[RapidRog]

Re: 1977 Johnson 70 hp

FOR JTEXAS: Will you send me your phone number for I'd like to talk to you. My email address is: rogmatthews@sbcglobal.net
Thank you very much.

 

[jtexas]

Re: 1977 Johnson 70 hp

FOR JTEXAS: Will you send me your phone number for I'd like to talk to you. My email address is: rogmatthews@sbcglobal.net
Thank you very much.

I'd rather not.

Repair & maintenance of that motor is well within the scope of the average do-it-yourselfer with some basic tools & a good service manual, even if you never turned a wrench before. You can get the original factory shop manual, about $45, from www.outboardbooks.com or www.marineengine.com - it has saved me literally $thousands.

Starts with compression & spark tests.

Do the compression test before spending any more money on it, it'll indicate the basic health of internal engine components. Follow the "compression testing" link from the "top secret file" at the top of this forum. Compression tester, less than $40.

 

[RapidRog]

Re: 1977 Johnson 70 hp

JTEXAS:
Thank you for all of the tips. I have changed sparkplugs (found one of the leads from the coil very loose), replaced the gas and added some JE fuel conditioner. I've also advanced the idle screw a couple of turns. I n\hope to put it back in the water later this afternoon.
You mentioned "top secret file". Where do I find that?

 

[jtexas]

Re: 1977 Johnson 70 hp

top secret file is the very first thread in this forum.