johnson 3 hp model j3renm

[jeremy r]

the motor will not run full throttle, but will run full throttle in idle at high rpms , like its bogging down when you open it up goes into gear fine, but seems like its only half power when you try to go full throttle what could be wrong?

 

[Vic.S]

check it has a good spark on both and is firing on both cylinders. Do cylinder drop test.
New plugs if in doubt ( Champion QL82C gapped at 0.030")
Check compressions if you have, or can beg, borrow, or steal, a compression gauge

​Then suspect that it needs a carb clean, esp the high speed nozzle and orifice.
Check the little bladder that forms the fuel pump when using the integral tank while you are looking at the carb

 

[jeremy r]

ok I will do that, also I have to transport the motor inside the boat laying on its side don't have a trailor yet will this hurt the motor? someone also told me that the lower gear unit oil prolly needs changed it could be tight I have no idea what that means, I keep the motor inside when im not boating standing up no boat dolly motor yet, and I accidently broke a plastic threaded piece on the throttle cable tinkering with it but I had this problem before that, but I did noitice a nut was loose the first time I opened up the motor plastic housing don't know reall how that throttle works with the 2 nuts on each side of the plastic threaded piece around throttle cable I tried to upload pics but allways says error loading

 

[jeremy r]

oh what compression should it be if I can test it ? im new to boat motors so any help would greatly appreciate it

 

[F_R]

It runs, so don't worry about actual compression numbers, just make sure they are reasonably equal. What you are looking for is something drastically wrong with one of them.

Otherwise, I agree with what has already been said. It very likely is running on one cylinder. Very likely an ignition problem. Don't ignore the spark plugs.

 

[jeremy r]

the spark plugs that's it there are ql77jc4 vic do you recommend the spark plugs you posted ?

 

[jeremy r]

ok I just changed the plugs seems better but I dontknow if its me or the fact that I run in in water in a barrel before I go to the lake seemed to open up on wot hopefully it did the trick I have to try it on the water to know for sure

 

[Vic.S]

the spark plugs that's it there are ql77jc4 vic do you recommend the spark plugs you posted ?

Sorry that was wrong QL86C are the currently recommended plug although the originals would have been QL77JC4. QL86C are sightly hotter

 

[jeremy r]

turns out it was the throttle cable, piece broke off have to get it fixed plastic piece with threads that has two nuts on each side ???? for the throttle cable but still can run pretty good,