aferland66
New member
Hi, this is my first post so thank you in advance for any help you can give me.
I boat a used Johnson 70hp 1978 (70el78c) that I want to get running properly. I had a tune up done but the mechanic did not do anything to the carbs so I will have to get it done myself. Just so you all know this is my first boat, first time working on an outboard but I do have mechanical expertise in cars (of course they where all fuel injected). This is my first try and fixing carburator issues.
So I put the boat in the water after the tune up, tried to start the motor, and after multiple cranks it did start but would not idle properly even after a 15min warmup. Yes it's new supreme gas with 50:1 ratio oil. I got it running by shutting the idle lever quickly and putting it into gear real fast before it died, and it did run very well at high speed, but every time I put it out of gear it dies. I removed the motor cover and noticed a lot of gas and oil coming out of the bottom of the front of the engine and noticed oil in the water around the engine.
The compression is 118, 120, 118, motor is firing on all 3 cylinders, spark plugs are new with 30 gap.
I have since opened the air intake cover in the front of the motor and ran it at home to try and figure out what is going on. The carbs are leaking gas and oil from the front when at medium idle and gas and oil is leaking from the hose at the bottom of the manifold.
I have looked for an adjustment screw for the fuel and can't find one.
I have now pulled the carbs off the motor and will try a good cleaning, but everything I find on the net all talks about restricted gas flow and not enough gas, in my case it seems I have too much gas coming into the carbs. I have thought it could also be the gas spray not being fine enough and the gas is not being sucked into the piston and just flows out.
Noticed from my research that the top carb is not like what I see on the internet and does not have a top cover that can be removed.
So any input would be greatly appreciated so I can figure out what is going on.
I boat a used Johnson 70hp 1978 (70el78c) that I want to get running properly. I had a tune up done but the mechanic did not do anything to the carbs so I will have to get it done myself. Just so you all know this is my first boat, first time working on an outboard but I do have mechanical expertise in cars (of course they where all fuel injected). This is my first try and fixing carburator issues.
So I put the boat in the water after the tune up, tried to start the motor, and after multiple cranks it did start but would not idle properly even after a 15min warmup. Yes it's new supreme gas with 50:1 ratio oil. I got it running by shutting the idle lever quickly and putting it into gear real fast before it died, and it did run very well at high speed, but every time I put it out of gear it dies. I removed the motor cover and noticed a lot of gas and oil coming out of the bottom of the front of the engine and noticed oil in the water around the engine.
The compression is 118, 120, 118, motor is firing on all 3 cylinders, spark plugs are new with 30 gap.
I have since opened the air intake cover in the front of the motor and ran it at home to try and figure out what is going on. The carbs are leaking gas and oil from the front when at medium idle and gas and oil is leaking from the hose at the bottom of the manifold.
I have looked for an adjustment screw for the fuel and can't find one.
I have now pulled the carbs off the motor and will try a good cleaning, but everything I find on the net all talks about restricted gas flow and not enough gas, in my case it seems I have too much gas coming into the carbs. I have thought it could also be the gas spray not being fine enough and the gas is not being sucked into the piston and just flows out.
Noticed from my research that the top carb is not like what I see on the internet and does not have a top cover that can be removed.
So any input would be greatly appreciated so I can figure out what is going on.