1980 115hp johnson bogs at high speeds, bulb flat

I have a 115 johnson on a pontoon boat. It runs ok at lower speeds but when you run at cruising of wide open it bogs down terrible. I noticed that the bulb running from the gas tank to motor is squeezed flat. How do I fix this?

Re: 1980 johnson bogs at high speeds, bulb flat

speegler said:

I have a 115 johnson on a pontoon boat. It runs ok at lower speeds but when you run at cruising of wide open it bogs down terrible. I noticed that the bulb running from the gas tank to motor is squeezed flat. How do I fix this?

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Change the bulb, and it flows in the rigt direction, but make sure the bulb is a tight fit to the fuel lines, do not use the plastic clips, use stailess steel clamps. Also if you have a metal fuel tank, check the pick up tube for rust. I had this same problem on my 115hp.

Re: 1980 johnson bogs at high speeds, bulb flat

There is a arror on that fuel primer bulb that must point towards the engine. If the bulb is pointed in the right direction, see the following.

(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.

Re: 1980 johnson bogs at high speeds, bulb flat

I'm no expert but you may also want to look at your fuel tank vents. If it is not venting correctly it will pull a vacuum on your fuel system. Good luck. tgh3fan