Johnson 30 hp help

[Ouachita]

I ran my 1997 Johnson 30 hp in the lake last weekend for the first time in about 2+ years. It has been previously run in a barrel at home but only idling. It started fine and ran strong for about a minute. Then the rpms dropped and it would only run at idle speed. Initially I thought it was the fuel line. It had been kinked a little during storage. Changed it out and it did the same thing. I think there is a safety shutoff the limits the rpms if the motor starts to overheat. I was getting flow out of the pee hole and the motor didn't seem to be hot. I am going to go ahead and change the impeller as it hasn't been changed since I bought the motor 3-4 years ago. Maybe a stuck thermostat? Anyone have any ideas what the problem might be. Thanks.

 

[E-Rawk]

Carb may have dropped the main jet in the float bowl. (if it has one) Also check the Airfilter for any obstructions. I'm not a boat motor guy, but I had a race quad do the same thing that you are talking about once. I happened to be that the main jet in the carb came loose and fell into the float bowl. Idle's great then bogs down the minute you open it up.

 

[Jim]

Check the spark plug. It could be all fouled up. Thats what caused my issue.

 

[E-Rawk]

I always over complicate things. My wife and daughters are rubbing off on me.

 

[Ouachita]

Check the spark plug. It could be all fouled up. Thats what caused my issue.

Did it abruptly power down on yours? I had just gotten up on plane after leaving the ramp and it just dropped suddenly when at full throttle. Ran smooth at idle speed, but when I hit the throttle it just sputtered.

 

[Jim]

Check the spark plug. It could be all fouled up. Thats what caused my issue.

Did it abruptly power down on yours? I had just gotten up on plane after leaving the ramp and it just dropped suddenly when at full throttle. Ran smooth at idle speed, but when I hit the throttle it just sputtered.

Exactly what happened!

 

[Captain Ahab]

If it is sputtering then I agree - spark plug(s) or fuel problem. Generally, the overheat control will let the engine run smoothly at idle but when you hit the gas it just does not move up in the rpm range significantly.


Are you able to increase the RPMs when in neutral?

 

[Ouachita]

If it is sputtering then I agree - spark plug(s) or fuel problem. Generally, the overheat control will let the engine run smoothly at idle but when you hit the gas it just does not move up in the rpm range significantly.


Are you able to increase the RPMs when in neutral?

I didn't try that. When I hit the gas with it in gear it doesn't move up and it sputters like it is missing.

 

[Popeye]

How old is the gas?

 

[Ouachita]

How old is the gas?

new this week

 

[Ouachita]

well, so far I have replaced the spark plugs, fuel line, fuel tank (all three needed) and yesterday I replaced the impeller. I think this was definitely the problem.

It was pumping with only 3 of the blades still intact. When I put it in the barrel the water output was 3 times as strong as it was before. We had planned to take it to the lake today to try it out and were met with 50 degree temps and high winds in the Dallas area so maybe one evening this week I will put it in the water and see if it is fixed.

 

[Jim]

Wow look at that impeller. Surprised it even peed water at all!

 

[Quackrstackr]

I would say that impeller was a problem but not the problem.

If you get a motor too hot to run it's not going to idle very well either. I'm not familiar with if that motor would have an alarm but if it does, it should have been singing a tune for you.

I've had problems like you are describing in the past. They ranged anywhere from clogged jets to fuel pump diaphragms with pinholes to more serious powerhead issues.