9.9HP Johnson engine cuts out

[Zman-2]

I have a late 1980s or early 1990s johnson 9.9 hp motor. once I start it, it runs for a while then cuts out. The pressure on primer bulb always is gone when the engine dies. after priming it again she starts but dies after short ride. I thought it could be bad primer bulb, so a bought a new one and same problem continues. could it be a bad fuel connector or perhaps fuel pump? someone help, help me, please. I would like to use it this memorial day holiday. I have not repaired the motor myself -- so if it is the fuel pump, is it easy to install. The motor is a pull-start engine.<br /><br />Your help is greatly appreciated.<br /><br />Zman-2

 

[Chinewalker]

Re: 9.9HP Johnson engine cuts out

Some easy checks...<br /><br />Is the fuel tank vent open? <br /><br />To see if the fuel pump is working, prime it up with the bulb, then remove the fuel line from the carburetor. and route it over the side of the cowling into a clean coffee can.. Now, start the motor and note what happens. If you don't get a steady series of spurts of gas then the fuel pump is not working properly. If it does pump fuel then your problem lies elsewhere... <br />- Scott

 

[BF]

Re: 9.9HP Johnson engine cuts out

Hi & welcome,<br /><br />It doesn't sound like a clogged tank vent problem to me... if it was, then the bulb would be getting sucked flat, and loosening the fuel cap would relieve it. I think it's more likely to be an air leak somewhere in the fuel line (engine sucks air instead of gas). The bulbs don't normally say hard, but if you squeeze it, it should feel like there's fuel in it, and there shouldn't be air between the bulb and the motor. If there is no air between bulb and motor, then it's more likely to be a fuel pump I think.<br /><br />Borrow another fuel line to try, or check for potential air leaks at the fitting ends of your hose (or you could just buy another one). <br /><br />here's lots of info on your motor.<br /> 9.9 / 15 hp page <br /><br />good luck.<br /><br />Brent

 

[umblecumbuz]

Re: 9.9HP Johnson engine cuts out

Another old tip.<br /><br />Put grease round every joint between bulb and fuel pump. Then see what happens. If motor runs fine, remove grease from each joint in turn, starting at fuel pump end. If motor dies after any joint is cleaned up, there's your air leak.<br /><br />Having said that, I go with Scotty every time - it sounds more like a punctured fuel pump diaphragm than anything else.<br /><br />And the site Brent mentioned is almost as good as a manuf manual.

 

[Swider]

Re: 9.9HP Johnson engine cuts out

I had the same problem. Turned out to be the vent cap.

 

[Zman-2]

Re: 9.9HP Johnson engine cuts out

Thanks guys for all those helpful suggestions. It turned out to be a faulty fuel pump. I replaced it with a new one and my little 9.9hp johnson runs good. <br /><br />I however have found something else mysterious. whenever I run the motor and then take it out and put on a hanging stand, I have noticed oily substance oozing out of the exhaust holes ( I think it is exhaust) right above the stablizer shield near the lower gear unit and also on the prop. I replaced the gear lube oil but the oozing continues. It does not appear to be oozing while in the water running because I do not see oil floating.<br /><br />This is what I am thinking-- I started the motor once by pouring some mixed gas directly into the spark plug holes. Some of the gas was coughed out after I started it. Could it be some gas got into engine parts and is thining lube grease and therefore causing it to ooze down??<br /><br />I am a rookie at this and I am not sure whether it is safe to continue running the motor. Please, please and please help. Your help is greatly appreciated.<br /><br />Good ridding and great outdoor life to you all!!<br /><br />____<br />zman-2