Need Help with 70HP Johnson

[cmchesse]

I am looking for some advise on what to do next.

I have done the following:
Cleaned the Carbs
Lync and Sync
New Plugs
New Ignition coils
New Power pack
New spark Plug Wires
New fuel tank and lines

With all this I have a few other issues on this engine. As you watch the video the bouncing yellow thing is a wire nut. The previous owner used several of them. My Winter project is to rewire the engine. In the mean time as you hear from the video it just seems to run ruff. If you advance the spark it runs better, but I just cannot seem to get it to idle very well.

Please help, I do have a manual and my father was a diesel mechanic. But we just cannot seem to get this engine to smooth out.

Please help!!!



by the way, I have a longer video available.

 

[bigpoppakdog]

Re: Need Help with 70HP Johnson

compression test. did you adjust for rich/lean?

 

[cmchesse]

Re: Need Help with 70HP Johnson

I forgot to list the compression

115 on all 3 cylinders. By Rich/lean do you mean adjust the idle screw? If so, yes. That was the only way I could get it to idle at first. With the new ignition parts we have slowed it down to what seems to be a normal setting. By the way, the wiring harness is horrible, so no tach.

 

[bigpoppakdog]

Re: Need Help with 70HP Johnson

how did you clean the carbs? How did you set the idle screws? you have spark at all 3 cylinders? fuel filter?

 

[cmchesse]

Re: Need Help with 70HP Johnson

On the Carbs, I removed and dismantled them, cleaned in fresh gas and blew out all the jets. No low idle on thecarbs, so adjsted the screw on the throtle linkage. The spark was not great to all 3 cylinders. That is why I changed the coils and powerpack. They all seemed suspect. I have an inline fuel filter that is brand new. There was no fuel filter on the engine.

 

[bigpoppakdog]

Re: Need Help with 70HP Johnson

hmm...i'll let the experts take over.

 

[Benny1963]

Re: Need Help with 70HP Johnson

run comp check spark test under load with timeing light
soak carbs iver night blow clean with air .
inspect reeds with carbs off .use guality carb kits check your float weigh them or just use brp complete kits sound like it dropping a cyl at idle or idle jets are clogged check your plugs and post back

 

[cmchesse]

Re: Need Help with 70HP Johnson

3 questions this morning,

When I cleaned the carbs I was not able to remove the low speed jet on 2 of them. The tabs were gone and I did not know how to remove them without it. I blew all of the jets out with compressed air and ran a small piece of wire through the low speed jets I could not remove.

Also, the motor is a 1985 model. Based on the condition, (and Wire nuts, lamp cord, and orage extension cord the previous owner used as a wire harness) I am not sure how old the fuel pump is. Would this cause idle issues? When I cleaned the carbs they were really clogged.

Will carbs from a 1977 model fit work on the 1985 I have? Would this cause any problems? Loss of power, fuel economy, etc.

 

[James R]

Re: Need Help with 70HP Johnson

Two big mistakes in cleaning the carbs. 1/. Gas will not clean the carbs.Dont use the "spray on" carb cleaner. It will not clean shelac out and will damage finish and plastic parts. Go to Advance Auto or similar and purchase the 1gallon carb cleaner made by the manufacturers of Gunk products. Follow the instructions and your carbs will be clean. If there was very heavy muck, clean them twice to be sure. 2/. Never run anything metal thru the jets. If you are lucky you will not have done any damage. Keep your fingers crossed.
If you dont have a manual you had better get one.
From here on always use Stabil in your fuel otherwise carb cleaning again a little way down the road.