9.9hp Mid 80's Johnson

[Gary A]

Problem: when running at higher rpm for short distance the motor runs out of fuel. The bulb from the gas tank feels firm but when I squeeze it the motor picks up rpm's again. The motor starts and idles without any problem.

What I am trying to determine is do I have a gas tank/line problem or a carberator problem. I am confident it is a fuel problem of some sort.

Any suggestions for resoution will be greatly appreciated.

Thanks

 

[bktheking]

Re: 9.9hp Mid 80's Johnson

How about a little motor history. Own it long? The reason i ask is for a baseline.

 

[Genonbamagirl]

Re: 9.9hp Mid 80's Johnson

How about a little motor history. Own it long? The reason i ask is for a baseline.

Replace the fuel line for about 15 dollars. if that works for a while and then she goes back to sluggish - it's the tank. That is assuming you have a metal tank.

New line and plastic tank will probably make the issue go away completely. Keep the old tank, drop some sand and a huge handfull of ball bearings in her, place her in the back of your truck or in your trunk and drive it around for a month. Get a tank coating kit and refresh her. Now you have two working tanks. If you drive like a grandmother, pay some kids to shake the snot out of it for several hours (or drive aggressively with the before mentioned setup).

 

[Genonbamagirl]

Re: 9.9hp Mid 80's Johnson

Replace the fuel line for about 15 dollars. if that works for a while and then she goes back to sluggish - it's the tank. That is assuming you have a metal tank.

New line and plastic tank will probably make the issue go away completely. Keep the old tank, drop some sand and a huge handfull of ball bearings in her, place her in the back of your truck or in your trunk and drive it around for a month. Get a tank coating kit and refresh her. Now you have two working tanks. If you drive like a grandmother, pay some kids to shake the snot out of it for several hours (or drive aggressively with the before mentioned setup).

Remove the ball bearings and every bit of sand or it will never run right again.

 

[bktheking]

Re: 9.9hp Mid 80's Johnson

Could be a weak fuel pump as well.

 

[kenmyfam]

Re: 9.9hp Mid 80's Johnson

I'm on the pump page at this time.

 

[bktheking]

Re: 9.9hp Mid 80's Johnson

If it was a tank or line issue it wouldn't start and idle after the issue presents itself. Correct me if i'm wrong but if it were a venting line issue the fuel bulb wouldn't be hard, it would be sucked dry of fuel.

 

[Rick.]

Re: 9.9hp Mid 80's Johnson

bktheking. Your right as rain. Like you mentioned, I'm thinking weak pump or clogged pump screen. If the line is old and hard I would replace all the fuel lines (from tank to the carb.) first just in case, although not likely, there is an internal collapse between the bulb and the engine. Rick.

 

[ENSIGN]

Re: 9.9hp Mid 80's Johnson

I would suggest putting a clear piece of hose between the carb and fuel pump,look for air bubbles I would put my money on a bad hose,pickup tube or fuel pump

 

[kenmyfam]

Re: 9.9hp Mid 80's Johnson

I would put my money on a bad hose,pickup tube or fuel pump

How much money ????

 

[Gary A]

Re: 9.9hp Mid 80's Johnson

Thank you for the input. I didn't state that I have a plastic tank. If it is the fuel pump, is there a way to test it? Also, would a carberator rebuild possibly help?

Thanks

 

[Gary A]

Re: 9.9hp Mid 80's Johnson

I received this motor from a friend who has had it for several years and he didn't have any problems with it. It sat for 2 years before I received it. I did replace the impeller but it pumps water good and I know that wouldn't have any effect on the fuel situation.

Gary

 

[kenmyfam]

Re: 9.9hp Mid 80's Johnson

I received this motor from a friend who has had it for several years and he didn't have any problems with it. It sat for 2 years before I received it. I did replace the impeller but it pumps water good and I know that wouldn't have any effect on the fuel situation.

Gary

Sat for 2 years.
Fresh gas
Clean and service the fuel system, especially the carbs. Could well be varnished up.

 

[bktheking]

Re: 9.9hp Mid 80's Johnson

I received this motor from a friend who has had it for several years and he didn't have any problems with it. It sat for 2 years before I received it. I did replace the impeller but it pumps water good and I know that wouldn't have any effect on the fuel situation.

Gary

That's what I thought, it sounded like a motor that you didn't own for long and it just started. Like Ken says, service the carb as a start, soak and put a kit in it, then possibly a fuel pump kit, that pump might be weak from sitting over time, possibly with gas in it.

 

[Gary A]

Re: 9.9hp Mid 80's Johnson

Thanks, I won't be able to attack it until late January but the first thing I will do is put a carb kit in it. Cleaning and installing a kit for the carb seems fairly straight forward. I will take pics along the way so I can back track if I need to. Thanks again for the help.

Gary A

 

[kenmyfam]

Re: 9.9hp Mid 80's Johnson

I will take pics along the way so I can back track if I need to.

Photos as you tear down are a great help. With digital you can keep them for future reference and dump the ones you do not need.