TOPIC: 1974 Johnson 85hp - running - but not the best.

finished swapping out my motor. I picked up a 1974 85hp johnson for a great price - came attached to a free boat & trailer : )


Took the boat out on the water this weekend & gave it the first shake out. In the water is always different than running it on the garden hose in the drive - you get a better idea of issues.


So here's the story - It is a little hard to start when cold (surprise!!) but once its warmed up it pops right to life & idles nice - though a little higher than I'd like.

On the hose I dialed the idle down as far as I possibly could - but on the water that took away my top end - so I've switched it back.

Question: Why would it have such a high idle - like 1500 rpm idle when I want it around 700.


Second issue - When I tested it I still had the idle set low with no top end, but a decent slow idle - but after driving at speed when I slowed down & went into neutral the engine races. I pump the high idle lever a few times & it drops back where it should.
When looking at this on shore - I shift & run it up to full throttle but when I return it - the cables return but the levers do not return all the way back. I pump the high idle lever & it cycles back to the idle position.

Question: Is this a lube issue for the throttle cable? Is there some other throttle return not adjusted right?

One thing I would do is disconnect the throttle cable at the engine. Then run the remote throttle up and down and see if the cable is sticking.

Do the same with the throttle arm on the engine. As you increase throttle, it should smoothly operate the carb linkage, and the timer base should move. Eventually you'll hit the spark advance stop and the spring-loaded throttle arm will continue to open the carbs to full throttle.

A very common problem on the V4's of this vintage is for the timer base to drag, due to corrosion buildup. Then you'll get erratic throttle operation and the engine may not achieve full power due to lack of timing; or the timer base won't go back to idle timing and you can't get the idle speed down to normal.

A good way to check this is to disconnect the linkage to the timer base. There's a rod attached to the throttle arm, with a ball on the other end that snaps into a plastic insert in the timer base arm.

Just snap the ball out of that socket and you should be able to move the timer base with your fingers.

If it's hard to move, or stuck, you may need to pull the flywheel to gain access. Pull the timer base and clean/grease the friction parts. If I recall the stator has to come off to get at the timer base.

Sometimes you may be able to just spray-lube from the bottom and loosen it up, then you wouldn't have to pull everything apart. But most times there's a lot of crud built-up and it'll have to come apart for clean/lube.

HTH & let us know what you find........ed

I fixed it!

The high idle cable where it goes into the controls box wasn't mounted correctly. There is a knob for lack of better term that goes into a metal stay or notch when you put the bottom of the shifter box back on.

I didn't have it correctly in that notch so when the throttle went up the cable moved as it should but when I throttled down it wouldn't go all the way back.

Once I fixed that I was able to adjust the idle & it runs like new!

I put the boat in the river yesterday & ran it for 30 miles!

Thanks for your help. I got my budget boat running like new!