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Johnson 70HP,1984 no power when in gear.

G

gapel33

New member
Hi.
Im getting problem with my outboard....... befor I bought this engine cought fire with previouse owner.Faulty rectifier blown all main harnesses.I did replace main harnesses,rectifier,spark plugs,power pack,new water pump with
water tube,fixed carbis(new carb kits) and still Im not happy how that engine runs.when its in gear is very low power performance.The Engine Idle fine.The engine is almost to die when trottles are open.The last think to do is fuel pump.Has that engine got fuel filter?Any one who ve got same issue.Thank u Jan
 
First, check compession... should be in the 100+ psi range and even on all cylinders. What are your readings?

Second, with the spark plugs removed, check to see if the spark will jump a 7/16" gap with a strong blue lightning like flame (a real SNAP!) on all cylinders. Does it? If not, describe what you have.

If the above areas are as they should be, I'd suspecct that you've overlooked something within the carburetor area. Did you manually clean the high speed jets that are located in the bottom center area of the float chambers? If not, do so with a piece of single strand steel wire.

Let us know what you find.
 
yes I did compression test ...top cylinder 115,125,125psi....I have done carbis ...i got kit to replace all seal,gaskets,needles etc.I played with idle screw and with linkages.So maybe then need to adjust.
Starts good running fine on idle ,perfectly responding ,when i pull throttle linkages down revs nice...after few minutes its different story....when i try to bring revs up dieing....no power at all...just idle fine.
Im to short at this stage.Spark are fine.....maybe i need to check timing,how can i adjust timing and put on right angle?
Thanks u helping me.Jan
 
yes I did compression test ...top cylinder 115,125,125psi....I have done carbis ...i got kit to replace all seal,gaskets,needles etc.I played with idle screw and with linkages.So maybe then need to adjust.
Starts good running fine on idle ,perfectly responding ,when i pull throttle linkages down revs nice...after few minutes its different story....when i try to bring revs up dieing....no power at all...just idle fine.
Im to short at this stage.Spark are fine.....maybe i need to check timing,how can i adjust timing and put on right angle?
Thanks u helping me.Jan
 
The timing on your motor is " fixed " at the factory and it should not be messed with.----------------Did you remove the highspeed jet ( orifice ) in the bottom of the carburetor float bowl for cleaning ?????-----------------Have you removed the float seat from carburetor body for cleaning and to blow out any debris that might be there ??---------------Your waterpump impeller has been replaced ???----------------It is not uncommon for folks to have to take carburetors apart a couple of times to get it right.-------------Sometimes you have to do what the teacher / coach tells you to do !!!
 
The last line in the "Racerone" reply above just about says it all. I asked and suggested making sure that the high speed jet is absolutely clean (in not so many words).... the owner wants to talk about timing.

Now, are you sure those high speed jets (all three of them) are thoroughly clean? If any of them are restricted, the engine will fall on its face when throttle is applied.
 
yes I have done it...they are clean....no dirt nothing....I just pulled fuel pump out....I got kit to replace all gaskets and seals.Its look to me pretty old and one of rubber gasket (round one got a lot of small cracks around).I ll see it tomorrow
when I split it in pieces.I ll let u know guys if any difference.....Thanks Joereeves and Racerone.Gapel
 
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