1980 Johnson 150 not running right need help

[Milligan123]

I have a 1980 Johnson 150 on a 18 foot bass boat. It takes the motor a while to get on plane. When the motor planes out it runs good for about 300 feet then Boggs down. I have cleaned the carbs and have checked the timing. I think I am getting to much fuel or not enough. But from a stop the motor does not feel like it has the power that it should that motor should up my boat up on Abe no problem. Can anybody help

 

[Bosunsmate]

try manually priming engine with primer ball, might be the fuel pump
then check spark and compression

 

[Milligan123]

I tried priming the ball while I was wide open yesterday. Motor had a little more but then bogged down couple seconds later

 

[Bosunsmate]

check primer bulb holds firm with engine off

 

[emdsapmgr]

Hard to fault the fuel system, esp if it does not pickup any rpm's when you constantly prime the fuel hose bulb a WOT. Any results when you checked for spark on all 6 cyls?

 

[Milligan123]

I checked spark and everything is good. Compression is good. The primer ball is not holding pressure when not running. I'm going to change it out when I get home today.

 

[pn]

a primer bulb that goes soft while not running indicates a bad float or needle valve sticking open or a bad fuel pump diaphram, or a loose fitting. try pumping up firm adn take a looksee areound.

 

[Milligan123]

I switched fuel bulb and righted some stuff and put some new fuel lines in. And everything is holding pressure good. I'll be taking it out for a test drive this weekend. So we'll see how it does

 

[Milligan123]

Motor gets up on plane faster but I'm still having an issue with the motor bogging down. I think it is a fuel issue what should I try next. I'm going to disconnect my fuel tank and hook a portable one to is if the pressure changes. After that I'm thinking the fuel pump

 

[Milligan123]

Motor gets up on plane faster but I'm still having an issue with the motor bogging down. I think it is a fuel issue what should I try next. I'm going to disconnect my fuel tank and hook a portable one to is if the pressure changes. After that I'm thinking the fuel pump

 

[Bosunsmate]

compare your spark plugs

 

[emdsapmgr]

If a friend constantly primes the fuel hose bulb and the engine will run fine at WOT, then you have a fuel supply issue. Are you using a 3/8" fuel line? These are things to check: ball valves in the hose bulb, anti-siphon valve at the top of the tank, fuel pickup tube in the tank. Testing with another supply hose and tank is a good idea. Keep in mind that any original fuel hoses inside the cowling are not rated to handle ethanol-blended fuels. They can break down and bits of hose can migrate downstream into the carbs and possibly cause problems. If you have any original 1980 hoses still on the the engine, probably best to replace them.

 

[Tim Frank]

how did you test spark?