johnson throttle problems ?

[JamesM56alum]

Iv got a 5.5 johnson seahorse and for some reason it doesnt go full throttle, even looking at the handle it wont go wide open. I havent touched the throttle linkage because i dont want to break anything cause it's a pain in the rear here to find parts for that motor and i dont want to ruin my chance at fishing opener in march.

 

[bbstacker1]

I think you need to be a little more specific as to the year of the motor. Does your motor have a neutral safety on it? If it does and you are in neutral the throttle will not open all the way.

 

[CodyPomeroy]

This may be a shot in the dark, but I have a '68 6hp johnson and had a similar problem. It was intermittent. I would be going along fine, and the throttle down for some reason and it wouldn't go back up. I figured out the problem was a colar that was labeled with "Off, Start, Slow, Fast", and this colar was slipping under the handle that turns to operate the throttle. All I had to do was wrap a ziptie around it so it wouldn't move. Problem solved. Maybe this helps. If not, good luck...

 

[richg99]

Many motors have a "fail safe" slow-down process. If the motor recognizes low oil; improper cooling etc. it kicks into a slow speed to save the engine. A manual will tell you what to look for. Often the "fail-safe" mode is accompanied by a beep or whistle signal of some kind.

Just one more thing to think about. R

 

[Pappy]

No fail safes on a 5 1/2! That engine was built long before that was ever thought of. To begin with how do you know it is not going to full throttle? The way to tell is to twist the throttle grip and watch the throttle shaft rotation and see if it is either coming up against it's stop or is rotating to a roughly vertical position. If not chances are your gears between the throttle handle and the steering bracket are either mis-timed or severely worn. There also may be a worn or broken drive pin that sits at the bottom of the vertical shaft that rotates the mag plate. That drive pin is visible in the slot on the driven gear in the steering bracket. If that engine is built prior to 1964 I sincerely hope you are running it on a mixture of 24:1 instead of 50:1. If some rocket scientist buddy of yours has led you to believe that it can be run on 50:1 then take a look at the Sea King thread a few down from this one. This is exactly what happens when a plain bearing engine is run on insufficient oil.

 

[richg99]

Thanks Pappy for the clarification. You the man!

R

 

[JamesM56alum]

Thanks for the replys guys, sorry i wasnt more clear it isnt the sound of the engine thats got me wondering it's the actual throttle linkage, the motor doesnt slow down sporadicly it just doesnt seem to go full throttle when looking at the handle as i turn it, You have the dial that says Stop,Start,Shift an then the high an low throttle, as you twist it it wont go all the way into the high it just stops, im not use to working on small engines so bare with me lol

 

[bbstacker1]

As Cody said about, it may just be the indicator sleeve moving.

 

[JamesM56alum]

I will check that thanks! also i run 16:1 do you think thats a little rich ? Hopfully not lol iv got a 3 gallon tank full in the boat and it would be a shame to not be able to use it in the boat.

No fail safes on a 5 1/2! That engine was built long before that was ever thought of. To begin with how do you know it is not going to full throttle? The way to tell is to twist the throttle grip and watch the throttle shaft rotation and see if it is either coming up against it's stop or is rotating to a roughly vertical position. If not chances are your gears between the throttle handle and the steering bracket are either mis-timed or severely worn. There also may be a worn or broken drive pin that sits at the bottom of the vertical shaft that rotates the mag plate. That drive pin is visible in the slot on the driven gear in the steering bracket. If that engine is built prior to 1964 I sincerely hope you are running it on a mixture of 24:1 instead of 50:1. If some rocket scientist buddy of yours has led you to believe that it can be run on 50:1 then take a look at the Sea King thread a few down from this one. This is exactly what happens when a plain bearing engine is run on insufficient oil.

 

[JMichael]

You can change it to 24:1 without wasting it. Pour one gal out into another container, then refill the tank with 1 gal of straight gas and that will make the fuel in the tank 24:1. Add 1/2 gal of straight gas to the gal you poured out and now you've got a total of 4.5 gals of 24:1 ready to use.

 

[Pappy]

Jmichael is correct on the ratio....and his math is pretty good as well !!
You can run 16:1 in that engine if you want with no detrimental effects however. Most of my classics (such as yours) run at 24:1 on the newer oil and my earlier vintage and antiques such as my opposed engines run at 16:1 using Aeroshell.
Main thing to remember here is that there is no substitute for using enough oil. The early engines have plain bearings vs roller bearings and have to have it for proper lubrication no matter what Billy Bob or Bubba tell you!