83 Johnson 70hp outboard want run full power on water

[TLW64]

My 83 70hp johnson outboard want run full throttle on water . i have adjusted all cables rebuilt carbs (twice in fact) replaced fuel line all new lines on carbs new fuel tank everytime i go to the lake the engine cranks and idles great but when i go to full throttle i have very little power on land i can hook up the ear muffs and have no problem but in the water i have to ride around for about 20 to 30 minutes then if i press the primer in and out several time the engine will sudenly jump a few time the all power comes. but if i stop and then try it again it does the same thing but doesnt take as long to get going this time. the prop is not slipping . i have double checked to make sure the high speed jets are open . new plugs on land with the earmuffs hooked up in gear the motor has a slight miss every now and then but other wise runs greathave checked resistance on plug wires but not sure on how to check coils . If anyone can help with this problem please let me know . thanks

 

[JB]

Re: 83 Johnson 70hp outboard want run full power on water

Howdy, TLWilkes.<br /><br />Have you verified that it is running on all three cylinders and that it has spark to all three?<br /><br />That engine will start and rev just fine on 2 cylinders with no load.<br /><br />From your description I would suspect that you are missing one cylinder until the ignition parts get warmed up.<br /><br />You need to do some reading. Do a search for power loss.<br /><br />Let us know what you find.

 

[Steve135]

Re: 83 Johnson 70hp outboard want run full power on water

tlwilkes I am with JB on this. I had a bad cd3 powerpack. It did just what you said till it got warm. Go out and pull a plug and listen . I hit it on the first try. Pull # 1 and it stalled.You should also check to see the timing is advancing. It will rev. in the driveway on muffs but won't in the water if the timing isn't advancing also. This could be from old grease that heats up also with the engine just look to see the top arm moving fwd with throttle advancement. You can do this with thee motor off. <br />steve

 

[TLW64]

Re: 83 Johnson 70hp outboard want run full power on water

Thanks for the information JB i will try testing the cylinders for firing this weekend will let you know what i find . tlwilkes

 

[TLW64]

Re: 83 Johnson 70hp outboard want run full power on water

HI stinky2 i will test the cylinders this weekend like JB said but i also noticed that with engine off when i go to full throttle that the advance is very slow to respond .The rod takes a long time to go to full advance. could be what you said you have ran into in the past . if so do i need to remove the flywheel to get to the problem are is there an easier fix . thanks for any info you may have . tlwilkes.

 

[Hooty]

Re: 83 Johnson 70hp outboard want run full power on water

The part about bumping the primer and getting a responce leads me to lean towards a fuel/carburetion problem. <br /><br />c/6<br /><br />Hooty

 

[spaznkat]

Re: 83 Johnson 70hp outboard want run full power on water

my 15 johnson did exactly the same thing. i took it in and it had a tune up and the carb cleaned. it ran fine for 2 days and did the same thing again. i'm thinking the carb or gas has problems.

 

[TLW64]

Re: 83 Johnson 70hp outboard want run full power on water

Hey guys i tested the cylinders today compression was 125psi on all three . Found that #3 cylinder was not firing tested coils and all three tested good . Found that i could wiggle wires going into power pack and #3 cylinder would start to fire . Going to try another power pack / will let you know if it takes care of problem . tlwilkes

 

[G DANE]

Re: 83 Johnson 70hp outboard want run full power on water

Hi tlwilkes<br /><br />It is usually possible to remove some of the poly on back of the PP and solder a new wire on. My 1988 that I am going to make ready for the summer has same kind of slow moving stator plate as you describe. It kind of follows trottle slowly by spring power is this normal ??? Or should I ( any you )pull flywheel and wash all old grease away, regrease and assemble ??

 

[JB]

Re: 83 Johnson 70hp outboard want run full power on water

That's a good question that deserves its own thread, G Dane.<br /><br />I would get in there and free the stator up to track the throttle.<br /><br />Good luck.

 

[G DANE]

Re: 83 Johnson 70hp outboard want run full power on water

Thanks JB<br /><br />I guess tlwilkes, stinky2 and I will have to pull our flywheels then.

 

[TLW64]

Re: 83 Johnson 70hp outboard want run full power on water

hey guys the power pack fixed my problem . thanks for the help. tlwilkes