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85 Johnson 70 hp not running well

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fmarando

Contributing Member
I took my boat out for the first time this year and my motor ran poorly. The motor is a J70ELCOS. Last fall on my last trip I ran the carbs out dry before I winterized it. It started and idled OK but it wouldn't go much over 2000 rpm out on Lake Erie today. When I got home I did my basic checks. 125 psi compression in all 3 cyls. 3/8 bright snappy spark on all 3. Fresh gas in the tank. Should I pull, clean and rebuild the carbs next?
 
is the timing advancing?after you check that the decision is it fuel or fire?...use an inductive timing light and make sure all 3 are firing at time of failure..you dont want to work on carbs if its a firing problem and vice versa..
 
I did check all 3 with my timing light while the motor was running on muffs and all flashed about the same, then I checked the strength of the spark with my air gap spark tester. I should make sure the linkage that advances the timing is functioning properly then try cleaning the carbs, especially the hi speed jets.
 
fmarando said:
I did check all 3 with my timing light while the motor was running on muffs and all flashed about the same, then I checked the strength of the spark with my air gap spark tester. I should make sure the linkage that advances the timing is functioning properly then try cleaning the carbs, especially the hi speed jets.
Click to expand...

Simple fixes for simple people. I checked the linkage and could readily see the timing advance. After I actuated the control lever back and forth a few times I noticed something obvious. The throttles of only the top two carbs were opening. The linkage rod had popped out of the plastic clip on the bottom carb. (Probably when I replaced the primer solenoid last week.) So the malfunction was self inflicted and fortunately easily self repaired. Lesson learned: when you play around near the carbs check all the linkages when you are done.

I learned a lot about this motor and outboards in general on this site over the past few years. Thanks to Papyson for pointing me in the right direction before I started buying carb kits.
 
glad it was simple...we all are in continuous learn mode on this site...don't forget they sell parts and supplies here...good prices and delivery..i have used them...
 
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