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1991 Evinrude 70hp Getting fuel in the bottom cylinder

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Will Wrenn

New member
I have a 1991 Evinrude 70hp getting fuel in the bottom of the cylinder. I just rebuilt the carburetors and adjusted all of the floats to spec. When I prime up the motor with fuel I not only get fuel pouring out of the intake side of all carburetors but I realized that fuel was getting into the bottom cylinder causing the motor to struggle cranking. I am also having an issue with no spark getting to the motor. Any help would be appreciated thanks.
 
Few questions that must be answered.-----What fuel pump is on this motor ?----VRO or something else?----Does tell tale hose come off the side of the exhaust manifold or top of the engine block?
 
Red lever on the electric primer valve in the correct position.-----And You may have to revisit carburetor float / float valves.
 
Will Wrenn said:
I have a 1991 Evinrude 70hp ...I just rebuilt the carburetors and adjusted all of the floats to spec. When I prime up the motor with fuel I not only get fuel pouring out of the intake side of all carburetors...fuel was getting into the bottom cylinder
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If the floats are adjusted properly you should never have fuel coming out the carb throat when pumping the primer bulb. If you are getting fuel coming out all 3 carbs then there is either something missing or the floats aren't set right. Be careful, the carb rebuild kits cover many different model years and will come with a washer (circled in red) meant for the seat. Not all carburetors use this washer and if you install it when not needed, or leave it out when the washer is required, it will drastically effect your float adjustment.

SOP for setting floats is to install the seat, float, pivot pin, and needle in the carb body. Next, hold the carb upside down, looking at the side of the carb you want to have the float parallel to the carb body or the end opposite the needle can be about 0.010" higher. Anything different than that is incorrect and will cause issues.

Fuel getting in the bottom cylinder sounds like a possible bad fuel pump diaphragm allowing fuel to flow through the pulse hose into the crank case. It might be something else, but that's the first thing I would check. Leave all fuel hoses installed to the fuel pump but remove the pulse hose. Next, pump the primer bulb and look to see if any fuel is coming out of the pulse hose fitting. If fuel comes out, you have a bad diaphragm but if not, your problem is elsewhere.

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racerone said:
Few questions that must be answered.-----What fuel pump is on this motor ?----VRO or something else?----Does tell tale hose come off the side of the exhaust manifold or top of the engine block?
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I’m not to sure what fuel pump is on the motor. And the tale hose comes out the left side of the motor but exits on the right hand side of the engine
 
kevinj said:
If the floats are adjusted properly you should never have fuel coming out the carb throat when pumping the primer bulb. If you are getting fuel coming out all 3 carbs then there is either something missing or the floats aren't set right. Be careful, the carb rebuild kits cover many different model years and will come with a washer (circled in red) meant for the seat. Not all carburetors use this washer and if you install it when not needed, or leave it out when the washer is required, it will drastically effect your float adjustment.

SOP for setting floats is to install the seat, float, pivot pin, and needle in the carb body. Next, hold the carb upside down, looking at the side of the carb you want to have the float parallel to the carb body or the end opposite the needle can be about 0.010" higher. Anything different than that is incorrect and will cause issues.

Fuel getting in the bottom cylinder sounds like a possible bad fuel pump diaphragm allowing fuel to flow through the pulse hose into the crank case. It might be something else, but that's the first thing I would check. Leave all fuel hoses installed to the fuel pump but remove the pulse hose. Next, pump the primer bulb and look to see if any fuel is coming out of the pulse hose fitting. If fuel comes out, you have a bad diaphragm but if not, your problem is elsewhere.

View attachment 36435
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That’s what I was thinking the fuel pump diaphragm was bad. The engine has been sitting for a while and I know I rebuilt the carburetors correctly and made sure I had the red washer under the brass fitting where the needle valve goes
 
I am still getting no spark to the motor. I am not sure if it is bad coils or could it possibly be a stator how do I go about testing the stator if possible thanks
 
I can not see your motor !-----There was a service bulletin in 1994 to move tell tale hose to the top of the block.-----Is the VRO pump on this motor , yes or no or no idea what that is ?----Charge the battery and have it load tested.----Take starter apart for inspection and ohm test on armature.
 
Does it come off the TOP of the block or way down on the side?----The VRO pump is fairly big / plastic and has wires coming out of it for the no oil warning.----Do you mix at 50:1 in your fuel tank ?
 
How did this motor run for you last season ?----Post the results of a compression test.-----Is the VRO tested and actually in service?
 
racerone said:
How did this motor run for you last season ?----Post the results of a compression test.-----Is the VRO tested and actually in service?
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I am working on this boat for a friend of mine. He said the last time it was parked it ran fine. I’m not sure how true this is because every time I dive deeper into the motor I find something else wrong. I also have no spark to the motor I haven’t ran a compression check on the engine yet but I will do that. How should I go about getting spark back to the engine. I put a spark tester on it from the coil to the spark plug on each cylinder and I have no spark.
 
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