1982 Johnson 115 v4 fast idle problem

[Hildy39]

Hi
I'm new to the forum and new to boats. I bought an older boat with the 115 Johnson. It had been rebuilt 6 years ago and then parked since. I got it running but it idles wayyy to fast. The idle screw on the engine does not touch the stop point when the lever is all the way down. And the lever only responds once halfway up. Can I adjust that fast idle cable so that when the lever is down the screw touches the stopper and in turn slows down the idle speed? If so, how? Without saying take it in please. Is there a way I can do it myself. Thanks.

 

[rothfm]

Yes there is...Not really that hard. You may be able to adjust that cable using the knurled round knob on the cable end, providing all the other link and sync items are proper.

Or You will need an OEM Manual and follow the "Link and Sync" procedure. There is a write up here under the "sticky" area. The cables, cams and levers all need to work together correctly for the motor to be properly setup and in time.

 

[Bosunsmate]

Undo the throttle cable and run it manually by hand, once you have that right then move on to the cable to finish.
Post some photos of it if you get stuck, link and sync the throttle and timing does get a bit tricky until you get the hang of it

 

[Hildy39]

ok thanks..I will tinker this weekend. Just to be clear …undo the cable at the engine end?

 

[Bosunsmate]

Yes undo the nut and slide the throttle cable off.
Check how the engine goes by operating the throttle arm manually forward and back and if you are happy with that (timer base moving) timing etc then put back the cable and adjust the cable. The cable is the last part to be adjusted, and its adjusted to fit the motor.

Two things can cause problems here, one is if the cable is very worn and two if the timing bases grease has stiffened up or got dirty, that can stop the timing base going back to the stop when the cable trie and pulls it back

 

[Bosunsmate]

I had problems this week with mine not moving back properly, im just pulling my boat out for spring here in the southern hemisphere. What had happened was the timing base was dirty and the little screws which hold it down had come lose, i could see that by looking under the flywheel and seeing a little plate move when the timing base was moved back and forth with the throttle. I took off the flywheel cleaned out the grease gunk and did the screws up with a bit of locktite and its now moving fine back to the stop,
My cables are worn, they are a 1982 as well but it wasnt them that was the issue.
So yes undo the cable at the engine and see how it goes without them

 

[Hildy39]

Thanks for the info. I probly won't have time till Saturday evening.

 

[emdsapmgr]

Keep in mind that the idle rpm's on that engine are not set by a carb adjustment alone. The idle rpm's are primarily set by adjusting the idle timing degrees. Agree, you need to read the sync and link section of the factory manual in order to set the idle properly.

 

[Hildy39]

I got it to idle slower but now it's a hair too slow. All is good with the exception of a couple gauges not working. Thanks bosunsmate !

 

[Hildy39]

Another question. Everything is good. But the speedo doesn't work. Traced the cable from the gauge back to motore and it's basically just sitting there loose. Can anyone tell me where it attaches or if I have to purchase something. ? Thanks

 

[Bosunsmate]

There should be a hole at the front top of the gearbox. A little tee comes out of there where the hose to the gauge connects too.
Its more often then not knocked off.
But if its a wire cable you are meaning that sounds like the rpm tach gauge, that hooks up to the rectifier on the starboard side of the motor

 

[Hildy39]

It's a hard-ish black rubber cable. Looks like it would go on a tee so I'm thinking that's the one

 

[Silvertip]

That's a plastic tube. It connects to the pitot on the lower unit of the engine.

 

[emdsapmgr]

Regarding your idle rpms. You can't set the idle on the trailer. Has to be set when the boat is floating normally in the lake-set it when the engine is idling in forward gear. Set for 650-700 rpm's. That engine should idle around 1100-1200 rpm's when running on the trailer in the back yard. There is a huge difference in the exhaust backpressure when the prop is submerged 20" underwater.