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1997 johnson 70hp full throttle problem

arild_johannessen

Contributing Member
"With the throttle wide open,the engine runs only with 3/4 of the rpm it should have. Then after some minutes,suddenly the "rest" of the rpm comes
and the engines runs like it should until next time starting from idle and "throttles up".

Any suggestions?"
 
"My guess , you have one carb

"My guess , you have one carb not 'starting' the main. The 3 cyl's are a bit tricky on that from time to time.
If idling OK, forget about ignition.
Do following test at sea:
Remove the front cover of the carbs and try to accelerate.
If lagging, then VERY swiftly block one carb throat after the other and see if that helps. You may even be able to see which carb that does not deliver.
This test is a bit off recommended, as they carbs may have problems 'starting' the high speed system with the cover removed, but try anyway."
 
"Hi Morten !
I will try that


"Hi Morten !
I will try that when the weather up here in "the old country" gets a little warmer,now its about 10-15 below.
If this is the problem then what? new carb or?
Are you sure its safe to run engine at high rpm with cover off?

By the way. Remember the Ev. 115 with idle problem I had? Changed both carbs and problem was gone. Sold it when summer was over.

The Johnson 70 its my brothers,and he asked me fore help, so I thougt I should try here before start tearing things apart."
 
"Pull the carbs, and clean. Ta

"Pull the carbs, and clean. Take special notice of the main jet and float level. Float level slightly low and the problem gets worse."
 
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