Johnson 70 hp 3 cyl / 2-stroke dies when giving more throttle

[oldboat1]

Thanks, OK we will try. So the idea is that the air lock from time to time triggers a high temp signal which makes the engine run on low rev /emergency mode only? No overheat alarm is heard from the controller but it might be broken.

air lock causes engine temp to fluctuate. Overheating is the main threat, but temp fluctuation could likely cause uneven running. Change the impeller if you haven't done that in a year or so -- special kit was prescribed, I think, so might do a search here ("move tell tale" or similar).

 

[racerone]

There is no point testing for this problem on a hose , on the trailer !!!-------Does timer base rotate freely and easily ?-----When accelerating on the boat in the lake / river do the following.-----Look into the carburetor bores with a strong flashlight.-----Compare amount of fuel coming up the main nozzle tubes.-----When you find the problem you will likely say -----" that was easy "-----" If only I had known what to look for "-----Just my opinion as always.

 

[elyfinn]

Bernt< I am having the exact same issue with my 1984 Johnson. Did you ever fix the problem?