The fuel primer bulb collapsing indicates a fuel restriction, read on..........

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(Fuel Anti Siphon Valve)
(J. Reeves)

Many of the later OMC V/6 engines incorporate a fuel restriction warning via a vacuum device attached to the powerhead. If the engine overheats, or if you have a fuel restriction, the warning is the same.... a steady constant beep.

NOTE... Only the V/6 & V/8 engines have the above "Fuel Restriction Warning". The warning horn will not sound on the other models.

The fact that a engine is not overheating, but the warning horn sounds off with a constant steady beep, and that the rpms drop drastically would indicate that the engine is starving for fuel due to a fuel restriction. Check the built in fuel tank where the rubber fuel line attaches to the tank fitting. That fitting is in all probability a "Anti Siphon" valve which is notorious for sticking in a semi closed position. It will be aluminum, about 2" long, and the insides of it will consist of a spring, a ball, and a ball seat. If this valve exists, remove it, knock out those inner components which will convert it to a straight through fitting, then re-install it. Hopefully that cures the problem.

The above procedure will cure a restriction problem with the anti siphon valve as stated. BUT, it may also allow fuel to drain backwards to the fuel tank when the engine is not running (siphoning backwards) due to the fact that the carburetors/fuel pump etc are higher than the fuel tank. This condition is not an absolute as the valves in the fuel primer bulb usually prevent this backwards siphoning problem. However.... if this does take place, the cure would be to install a new anti siphon valve.

NOTE: There has been cases when the output valve in the fuel primer bulb would come apart, and the inner portion of the valve would actually reverse itself and be drawn back into the primer bulb's output valve body. This in effect would create a shut off valve and result in a fuel restriction. If this is the case, you should be able to feel something laying in the bottom of the primer bulb when held horizontally.

Johnson 110 fuel problem

Today I took the fuel line that is screwed into the internal tank out for the fourth time to check for restriction. It is made up of an aluminum tube threaded into a square 90 degree connector to the fuel line to motor. You cant just look down the middle to see if it is stopped up.
So first I blew air thru it with air compressor with no problem. Then I used a led light to shine in on the 90 degree connector and look thru the tube and could barely see the light. Finally realized that the tube would come apart and after removing the tube I removed a very long screen filter that was stopped up on the end.
I have everything back together and planning to test out this evening. Wish me luck.

starving for fuel

I am at wits end on this problem. I thought I had found the issue in the metal fuelline in tank. Took boat out today and still have the same issue, sometimes I cant even get the bulb to prime from tank and tank is nearly full. I have three new bulbs and fuel line and have the same issue with all.

Time to check the fuel pickup line inside the fuel tank.

I'm having the same issue on my 175. And I've rebuilt carbs changed all lines rebuilt the pump replaced pickup removed anti siphon valve replaced separator. Today I replaced the pulse limiter I'll post Results. Btw it runs mint on a 6 gallon tank

Johnson 110 fuel problem

I have replaced everything from the internal tank to the connector on the motor. I have had the carbs rebuilt by mechanic. Also replace the fuel pump.
I removed the metal pickup tube from the tank , took it apart, removed the screen that was in the tube and just knew that this was my problem. But same result, travel about a few 100 yds and engine dies from something.
Not even sure where to look now.

It's my understanding that the fuel primer bulb has also been replaced... and that the fuel supply line from the engione's pump clear through to the fuel within the tank is now absolutely a clear shot so to speak.

If so, does having someone constantly pumping the fuel primer bulb, acting as a manual fuel pump make any difference now?

Johnson 110 fuel problem

Not absolutely sure. I tried this yesterday with my wife running the throttle and I was pumping the bulb. The motor started loosing power and I am not completely sure it was motor or what.

I think I know how a outboard 2 cycle works and it is all mechanical except the electrical starting solenoid, correct? So is there any chance that the starting solenoid engages somehow flooding the motor. Reason I ask is that it starts acting like it is flooded after trying to get it running for awhile.

In questioning the operation of "the electrical starting solenoid,"... I a$$ume that you are asking about the "Fuel Primer Solenoid". If so the proper positioning of the RED lever should be carefully turned clockwise so that it is against its stop and aimed directly at the other end of the solenoid. This is the proper running condition.

To see if the unit leaking internally, simply remove one of the small lines that connect to the carburetors or intake manifold... whichever is the case with your engine, then pump the fuel primer bulb that leads to your gas tank. If the primer solenoid diaphragm is faulty, fuel will shoot out of that small hose.

Johnson 110 fuel problem

What I am asking/suggesting is can the fuel primer solenoid be activated without pushing in the key which is how I understand it is to be used. I can hear it click when I push the key. This may be grasping at straws but I have tried everything. I ask this because when it starts acting up on the water it starts acting as if it is flooded.
Today I straightlined the fuel line from tank to fuel pump. I plan to put the old fuel pump back on that I rebuilt. The primer bulb will now pump up with ease and in the yard with muffs it runs with no hesitation.
Motor has new plugs, new power packs, new plug wires, it has good compression, fires on all cylinders, had mechanic to rebuild carbs and it will run like new for only a few hundred yards before stalling.

The fuel primer solenoid can only be activated by pushing the key in which supplies 12v to its terminal OR by turning the RED knob so that it faces away from the solenoid.

Johnson 110 fuel problem

Then that is not the problem. Is there any other part that can restrict the fuel flow or flood the carbs?

When this problem takes place, press the key in to activate the Fuel Primer Solenoid. Does this make any difference... and if so, what difference?

Also, when this problem takes place, does the fuel primer bulb still have a tendency to collapse?

Your initial post #1 was that the engine was running out of fuel and that the fuel primer bulb would collapse which indicated a fuel restriction.... What makes you think that now a flooding condition exists?

Johnson 110 fuel problem

I do believe that I did have a restriction in the metal fuel line coming out of the internal tank. The metal tube had a screen inside that appeared to be stopped up with trash. I have now removed that screen and every other filter from tank to fuel pump.
I have done so many things trying to eliminate possible problems that I may have fixed one issue like the restriction and introduced a new one by replacing the fuel pump with another pump.
The reason I was asking about flooding is the last time I ran boat(after removing restriction in line) it ran fine for several hundred yards and then started acting like it was out of fuel. It would start back and run for another distance but shorter and died, still acting like it was out of fuel.
After several tries like this the motor starts to skip like it has flooded cylinder.
My plan is to put the fuel pump back on that I rebuilt, take to the lake with an external tank and see what happens.
I will report back.