1975 70hp Johnson - won't start after running

[AllatoonaBayliner175]

This has been an ongoing issue. I have rebuilt the carbs, put in a new stator, replaced the power box, replaced all three coils, new plug wires and plugs, replaced the lower unit oil (which was fine i.e. no water) but still the motor will just not start after running. Today we ran a short was WOT to a cove and sat for a few hours until we left. The motor started up first crank as always when she starts. Usually if it doesn't start first crank it's not going to. We ran back to the dock and right as I said "keep it running", it died. If I waited a bout 45 mins it probably would have started. It usually willl, But I am out of ideas. I've tried everything I can think of but one thing, Seafoaming the engine which is what I am doing tomorrow.
Is it possible that could be enough? Any other ideas?

 

[JDusza]

Re: 1975 70hp Johnson - won't start after running

Stalls at idle from running and then won't start right away after running...check.
I would start with the fuel system, trying to determine if it is flooding or if it is starving for fuel. One of those two.
What would you do to "keep it running"?
If you choke it to keep it running, you're starving for fuel.
Once it is stalled and won't start, check the spark plugs to see if they are wet or dry.
J

 

[AllatoonaBayliner175]

Re: 1975 70hp Johnson - won't start after running

I just happened to say keep it running as a joke when it does. Plugs seem a bit wet to me. Which carbs should I adjust?

 

[Daviet]

Re: 1975 70hp Johnson - won't start after running

Your carbs don't have any adjustments, they have fixed orifices.
You might try removing the air box cover, run the engine at WOT for awhile, and then watch and see if any fuel puddles in the carb throats when you shut it down. Maybe you have a needle seat in the carbs allowing it to flood when shut down.

 

[emdsapmgr]

Re: 1975 70hp Johnson - won't start after running

Looks like you've replaced most of the ignition system on that engine. All but the timer base. You should quality it to be sure it's not the problem. After the engine is well warmed up.

 

[AllatoonaBayliner175]

Re: 1975 70hp Johnson - won't start after running

Please forgive my ignorance, but how would I go about doing that?

 

[emdsapmgr]

Re: 1975 70hp Johnson - won't start after running

You can find excellent troubleshooting information for your specific engine at this website: cdielectronics.com They have specific measures to determine if the timer base qualifies as "good" or not. You may need to rent a "peak-reading" voltmeter from an auto parts store to measure the cranking voltage output of the timer base.

 

[ron riddle]

ive a 35 e77h it stared went three. Miles it died wont start back up

 

[F_R]

3 year old thread. Expect the moderators to move your question

 

[GA_Boater]

ive a 35 e77h it stared went three. Miles it died wont start back up

ron riddle Welcome aboard.

This would be moved but your question is missing too much. New motor to you, any recent work done or did it used to run well?

Look at the Help Tip on top of the page and start a new thread with your question.

Closed.