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70 hrs Johnson runs but not under load..

I

iwannafish

New member
okay so we have checked the spark (fixed low spark.. jumps 7/16) rebuilt the carbs and great gas flow... the only thing left is the advanced timing... 17 to 20 BTD according to the manual.. the only problem is.. the damn book don't tell you how to set or adjust it... :mad::mad::mad:

If anyone has a '78 Johnson 70hrs 2 stroke with three carbs.. could you please measure how far out the rubber stopper is from the the holding bracket under the fly wheel just above the carbs.. just to give me a starting reference point... ( the manual also says to have motor under a load and to rev up to 5000 rpms for my model)


please help because as my name says ; i wanna fish

thanks..
 
The timing normally does not change.-----It is fixed at the factory , not to be adjusted.------You have checked compression ????-------Checked flywheel key ????
 
yes we did that too... the old one was sloppy and worn.. and compression is ( from top to bottom) 125, 124, 123.... the funny thing is that the book says i should have a sealed control box.. and this one you can open and unscrew the wires jumping to the cylinoids ...
 
What " box " are you talking about ???-------------The 78 had a powerpack / cdi / ignition module that had a removable cover and all the connections have terminals with screws.-----------------The 3 cylinoids you are referring to are actually the ignition coils.-----When you run the motor on the boat , shine a strong flashlight into the carburetor bores and see / compare the fuel coming up the main nozzles.------------Very effective and cheap trouble shooting technique.---There may be a problem with reed valves / crankcase compression.
 
raceone is right .. i was talking about the coil.. and it turns out that one of the ornge wires was frayed and worn and it wasn't connecting right in the ingnition module.. she is back up on a plane .. thanks for the advice...

raceone ... thank you.. as you can tell this is the first boat that i've had to work on... hell it is my second boat.. but the last boat i had was put in the shop when there was a problem with the engine...it was my brothers engine and my boat... so truely the engine work is all new to me...
 
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