Engine bogs out and dies?

[fsutim]

1978 70HP Johnson, I did a complete carb rebuild, soaked overnight and replaced all jets screws. When I took it out to the lake the first time it ran great, two days later I take it out and it can barely even idle without stalling out. It would continually start and barely idle, and if you attempted to give it any power it would die quickly. As I was giving it throttle I tried to pump the fuel bulb at the same time to make sure it was getting enough gas and it would still die out. The engine then started to pick up and gain power after about two hours of running at low speeds but I noticed gas dripping out of the motor. Upon opening the outboard cover I saw one of the fuel lines leading from the middle carb to the T-connector that connects to the other carbs was loose and gas was dripping everywhere. Earlier in the day I took off the engine cover to examine everything a few times and there wasn't a fuel leak, I then fixed the fuel leak and my engine was back to the same problem. My question is, Any possible ideas why this leak would help the engine gain power which it hadn't been able to do all day? Also, At the end of the day I checked my spark plugs, sometime after taking off the top plug, some oil leaked out of the top cylinder hole, not much but enough to run down the engine past my second plug, Is this anything to be worried about?

 

[OBJ]

Re: Engine bogs out and dies?

Sounds like it's flooding out Tim. When the hose came lose, the engine got more are to go with the excess fuel and leaned it out to where you picked up speed.<br /><br />Make sure your choke plates stay open and that the needle valve floats aren't hung up.<br /><br />Next theory....Do all the cylinders have spark? Each cylinder spark should jump at least a 7/16" gap with a hot white spark. I'd start here and also do a compression test as well.<br /><br />Keep us posted.

 

[Scooby]

Re: Engine bogs out and dies?

Sounds like your vent is closed on the gas tank. Make sure the tank is properly vented.

 

[jim dozier]

Re: Engine bogs out and dies?

I agree with OBJ that it is flooding. It may be because of a jammed open float (try rapping on the carb bowls with a screw driver handle). You may also have set the float adjustment incorrectly when you did the rebuild. It may be due to a tear in the fuel pump diaphragm which can, depending on the location, inject fuel directly into the intake port of the cylinder to which the fuel pump is attached which results in a rich cylinder.