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1990 70hp johnson wont start

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sea nymph12

New member
hey guys im new to the site, i have a 1990 70 hp johnson outboard the im having trouble starting. i just rebuilt the carbs, new water pump, thermostats, plugs, wires, and head gasket. when i got to start it it will crank and crank, when i put my hand ove the carb to cut air off and richen it will fire up but not run for long and occasionly it will seem like the rpms just randomly jump up and take off. if i could have some advice that would be great.
thanks, Dan
 
Need to know the facts on the engine.-------Do you have spark on all 3 cylinders that will jump a gap of 7/16" with a snap you can hear ??------Does your electric primer click when you push the key in ??---Do you advance throttle while cranking ?------Do you push the key in while cranking ?--------Is the starter motor in good shape, as a slow cranking motor will not have proper spark ?
 
yes i have spark that will jump 7/16" with a snap in all 3 cyl, i have great compression in all 3 cyl, primer works good, i advance the throttle very little while cranking and the starter motor is good with a good battery
 
okay i got the motor running finally, it will only run for abour 2 min max then it will bog down. after it dies the primer bulb is soft (could my vro pump be bad and not keeping pressure to pull fuel and push into carbs. and when the motor is running the rpm just completly take off and the go back down before it bogs out. any help would be great thanks dan
 
Repair kits are available for VRO pumps. Primer bulbs do not have to stay hard after motor is running.------What happens when you operate the manual fuel pump ??
 
The VRO pumps are elegantly simple to inspect and repair.------Where does the hose for the water pump indicator exit the block ?-Is it from the side or from the top of the block ?
 
When testing the primer solenoid, did you check that fuel actually got through the nipples and into the intake, or just that fuel got out of the solenoid?
The solenoid is not a pump, it just releases the fuel pressure in the lines. primer bulb must be pressed hard before priming, and when cranking the fuel pump pulses gives the pressure.
One way of 'testing' the pump, is to have the primer solenoid 'open', and leave a hose down into a canister, then crank. Fuel should be pumped through solenoid and into cannister. On a VRO engine this will not happen at every turn of the engine as it will on the non-VRO engines due to fuel pump design.
 
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