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1979 johnson 70 hp stall issue

J

John Watkins

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hello all, my issue is when i am out on the water. every now and then when i take it from idle or slow idle to full trottle (or anything above idle really) the engine will sometimes (not always) stall. and then it is a bear to get started again even with the choke. takes anywhere from 30 seconds to 10 minutes to get running. other times the engine starts right up and i have no problems with it and can take it straight from idle to full throttle. does anyone have any suggestions as to where to start?
 
should i seafoam it first? this is the first time the boat has been in the water in 7 years and also the first time in 7 years the motor has really been started and ran. sorry i forgot to mention.
 
John Watkins said:
should i seafoam it first? this is the first time the boat has been in the water in 7 years and also the first time in 7 years the motor has really been started and ran. sorry i forgot to mention.
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Knowing that, I would rebuild the carbs right from the start. That way you're at a known good point with the carbs.

Are you comfortable taking the carbs apart and cleaning them? If you can do a tune-up on a car, you can rebuild carbs.
 
I am sure I can do it. Im pretty mechanically inclined but I would feel much better having a guide to follow and a list of things needed. This engine is a 3 cyl so it has 3 carbs. first boat motor I have ever worked on though. Also my first two stroke.
 
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John Watkins said:
I am sure I can do it. Im pretty mechanically inclined but I would feel much better having a guide to follow and a list of things needed. This engine is a 3 cyl so it has 3 carbs. first boat motor I have ever worked on though. Also my first two stroke.
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They're very simple.

I have a 1977 70hp johnson, and have rebuilt the carbs. You will need a special screwdriver for the jet removal, but that's it.

Grab a manual from this website, it walks you through it. I did it before I had the manual, but just from stuff I learned online, I did everything right after reading the manual.
 
Yes, do not do it without the manual. (plus it will come in handy for other things)
I did my 73' 65HP after sitting for 13 years.
I also took several before pictures. It was worth it. (engine is now in the 5th season on the water with little trouble)
Leftover fuel had turned to something that looked like tar.
A regular screwdriver can be ground down to fit.
 
jim18611865 said:
Yes, do not do it without the manual. (plus it will come in handy for other things)
I did my 73' 65HP after sitting for 13 years.
I also took several before pictures. It was worth it. (engine is now in the 5th season on the water with little trouble)
Leftover fuel had turned to something that looked like tar.
A regular screwdriver can be ground down to fit.
Click to expand...

The electrical/ignition system diagnostics section is worth the price alone. Everything else is like icing on the cake.
 
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