Fuel Delivery problem on 79 100hp Evinrude?

I have a previous long post about my ongoing problems here: http://forums.iboats.com/showthread.php?t=489547

To sum up, I have cleaned the carbs twice and replaced the starter. I previously had a problem with the engine cutting out and dying when i shifted into gear occasionally and then when i put it into WOT.

After replacing the starter and cleaning the carbs, I was able to get it started with the fast idle lever up, but when i put it down, the engine would die. After trying to make adjustments to the idle screw, the engine won't even start unless i spray fuel direct into the carbs, but dies moments after it starts. The 2nd time I cleaned the carbs, I adjusted the carb floats to about 1" below the carb as according to the service manual instructions (which say 7/8"-1 1/8" below level).

I am at a bit of a loss right now and have no clue what to do next. My thought is that it is definately a fuel delivery issue since i can spray fuel direct and the engine will at least start momentarily. Any suggestions or thoughts on what might be wrong or what I should do next? I really don't want to pay someone an outrageous sum to look at it, but I feel like I am about out of options. Thanks in advance for any suggestions.

Re: Fuel Delivery problem on 79 100hp Evinrude?

What happens when you squeeze the primer bulb?

Re: Fuel Delivery problem on 79 100hp Evinrude?

Monte1961 said:

What happens when you squeeze the primer bulb?

Click to expand...

Nothing at all. I have squeezed it when the idle lever was up, on its way down, and when it was all the way down and nothing at all happened. I have also done it while a friend tried to start the motor, and it didnt have an impact on the ability to start the engine at all.

I can pump the bulb to semi-firmness but it never gets rock hard. When I was able to get it started, the bulb was never firm either while the engine was running, it was always soft.

Re: Fuel Delivery problem on 79 100hp Evinrude?

When you cleaned the carbs did you remove and clean the idle orifices?

Re: Fuel Delivery problem on 79 100hp Evinrude?

Are they synced? Is the fuel pump diaphragm good?

Re: Fuel Delivery problem on 79 100hp Evinrude?

I was not able to completely remove them, but I was able to run small strand of wire through all of them except 1 of the low speed orifices. I then was able to spray compressed air through the jets i could access and they were seemingly clear. The one low speed jet i couldn't access is because one of the screws is so tight that I cannot get it clear and I was starting to damage the slot in the screw since it is soft and brass. Any chance I can maybe put the carb's into carb dip with that screw still attached? Along those same lines, can i re-soak in carb cleaner with the core plugs in?

Re: Fuel Delivery problem on 79 100hp Evinrude?

cr2k said:

Are they synced? Is the fuel pump diaphragm good?

Click to expand...

They are synched according to the service manual and I can't be sure if the diapragm is good or not. I am not quite sure the best way to test that?

Re: Fuel Delivery problem on 79 100hp Evinrude?

Anyone have any suggestions or tips on removing the brass screw covering the orifice? It is obnoxiously tight and I am starting to damage the slot in the screw with the amount of force I am using to try and loosen it. I can't really put it in the carb dip unless i get that screw out in order to remove the o-ring. However, I do have an extra o-ring, would putting it in the carb dip and letting the carb cleaner eat up that o-ring give me a better shot of getting that screw loose?

Re: Fuel Delivery problem on 79 100hp Evinrude?

bump