1977 Johnson 70 - Starts, idles won't go

Took my boat out yesterday & it started right up & idled smooth but when gave it throttle would not go. I had fresh gas. I did change out metal tanks for a Tempo plastic 9 gallon tank. What should I do?

Re: 1977 Johnson 70 - Starts, idles won't go

Lots of possibilities.Has the boat been laid up for a while.If so,dirty carbs are the hot topic this time of yr.Or fuel pump,squeeze the ball ,if it get better ,likely fuel pump.If the motor was running and lost power,then ,be sure to check spark and compression.

Re: 1977 Johnson 70 - Starts, idles won't go

Thanks for the reply. One thing I failed to mention is that while out trying to get it going, I had my son pump the bulb to see if it made a change, only 1 time when he pumped the bulb did it seem to make a difference.

Re: 1977 Johnson 70 - Starts, idles won't go

I took my boat to our local marine dealer thinking needed carb cleaning. They said carbs were fine, compression 125 on all 3 cyl., spark good. So they thought my problem in planing had to do with the CMC tilt/trim unit, pt130 IO have on my boat. But then put it in test tank & wouldn't run right. Checked coil, 1 not firing, then swapped coils around & firing on all 3. The expereinced guy is not there & the one that is, is puzzled by it. It seems to be afuel issue to me, other than the coil. What might ya'lls ideas be?

Re: 1977 Johnson 70 - Starts, idles won't go

As far as the spark goes, may have been a poor connection at the coils ground, making it intermittent?

If it is stalling when put in gear, may be time for a carb bath and rebuild. Will spraying pre mixed fuel into the carb throats pick her up? Also, check to see if the timer base (starboard side, under the edge of the flywheel, linked to the throttle lever) moves smoothly without sticking when you advance the throttle.

Take the airbox cover off & observe whether the throttle plates are parallel.

Also, the timer base should start it's travel before the throttle plates start to open, otherwise the old girl will fall flat when you give her the throttle.

BTW, "The expereinced guy is not there & the one that is, is puzzled by it.." What kind of a shop is this! lol