1984 90hp johnson fuel problem

[GerClaire612]

Driving a boat, it runs good for about a minute, ive rebuilt the carburetors, changed the fuel lines,. The previous owner took the vro off and put a regular fuel pump on it. I thought the fuel pump might be bad, so i took the fuel pump off my 1978 115 hp evinrude and put it on and no change. Im missing something, can someone please help i can push the key in to choke and itpicks up the rpms

 

[edfishing2]

Re: 1984 90hp johnson fuel problem

double check float height. Is gas old? Pull the drains out side of carbs and pump primer bulb to make sure flow is good.

 

[Joe Reeves]

Re: 1984 90hp johnson fuel problem

Did you manually clean the four (4) high speed jets with a piece of single strand steel wire? If not, do so. Sounds like they're somewhat clogged and you're bypassing them when you push the key in.

 

[GerClaire612]

Re: 1984 90hp johnson fuel problem

Yes i cleaned them with wire i will check the float level and while im at it im going to clean the carbs again it can't hurt thanks

 

[emdsapmgr]

Re: 1984 90hp johnson fuel problem

Sounds like it is running lean. What happens at full throttle if you constantly prime the fuel hose bulb? Does the rpm pick up?

 

[GerClaire612]

Re: 1984 90hp johnson fuel problem

It don't make a defferance when pumping the bulb

 

[emdsapmgr]

Re: 1984 90hp johnson fuel problem

What changes in the engine after that minute?. Does it shut down, do rpm's drop, what's it doing?

 

[GerClaire612]

Re: 1984 90hp johnson fuel problem

Drops rpm push key in picks back up

 

[Joe Reeves]

Re: 1984 90hp johnson fuel problem

You say "Drops rpm push key in picks back up."

When you do that, you are injecting fuel directly into the intake manifold, bypassing the carburetors. This indicates that you have overlooked something within the carburetors.

 

[GerClaire612]

Re: 1984 90hp johnson fuel problem

I thank i did I'm going to take a half day off tomorrow and take them apart i hope that's what i did

 

[GerClaire612]

Re: 1984 90hp johnson fuel problem

Finally took it to a shop, left bank power pack was weak, and it had water in the fuel (so i had two issues rather than one). Thank goodness i had an extra parts motor for it. Now i just have to figure out how to get the water out of the fuel, and there is ALOT of water in it. Don't know how it got in there, someone must have put it in there. I think my boy and the neighbor boy did it. But the motor runs great on a separate fuel tank.

 

[Joe Reeves]

Re: 1984 90hp johnson fuel problem

Water can be be purchased along with the fuel at any gasoline service station, especially at a marina. Been down that road myself.