johnson problem

J

Jacob Holliman

Cadet
Joined
Nov 25, 2011
Messages
11
hey folks im new to iboats needing some help... my 150 Johnson fast strike has a problem. could use some help. it acts like it runs out of fuel. rebuilt an cleaned carbs, new fuel lines an filter, tank cleaned. when i pump the bulb up i can pull of a fuel line an it pumps fuel out when i turn it over. but then it stops like fuel isnt makin it to the bowl or wut ever on the pump. any ideas?
 
J

Jacob Holliman

Cadet
Joined
Nov 25, 2011
Messages
11
Re: johnson problem

jus tried taking the gas cap off to make sure it was venting fuel still isnt getting to the pump unless i pump it but when i stop pumpin it doesnt makin flow.
 
HighTrim

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: johnson problem

Constantly pumping the primer bulb keeps the motor running?

Fuel pump is the culprit.
 
Faztbullet

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,938
Re: johnson problem

A cracked or leaking cover on vapor separator can cause the VRO not to pull fuel....
 
OutOfControl

OutOfControl

Petty Officer 3rd Class
Joined
Nov 26, 2011
Messages
92
Re: johnson problem

"Constantly pumping the primer bulb keeps the motor running?

Fuel pump is the culprit."

I can verify that diagnosis from experience!
Luckily we were within 2 miles of shore when she starting stalling out, had to pump bulb while someone else steered. Docking and loading the trailer was a real pleasure.
 
fshrgy99

fshrgy99

Seaman
Joined
Jun 4, 2010
Messages
69
Re: johnson problem

Maybe sucking air. How old are the lines? ANY fuel leak, drip or whatever when you're pumping the bulb is FOR SURE sucking air when it runs. Check the filter for clog. Try getting a long clear hose from the hardware store (like 10 feet), connect to your line at fuel pump and start a siphon from the tank when the boat is on the trailer. See any bubbles or crapola? ....that's the problem. no bubbles ... attach after the pump and crank/reinspect for flow. Also, 'how it sounds' is often a liar. Even sometimes will run good at idle and drop cyls or sparks under load so seems to run perfect on muffs then poops out when launched. I wasted a whole summer looking at the fuel side. Repeat, Outboards are LIARS. Don't assume anything.
 
J

Jacob Holliman

Cadet
Joined
Nov 25, 2011
Messages
11
Re: johnson problem

all the fuel lines are new an vaccum lines. no leaks anywhere. no trash in fuel system. have cleaned the tank. mixed a gallon jug of fuel last night an hooked fuel line rite into it. carbs cleaned an rebuilt. new fuel pump. im about to pull all my hair out.
 
J

Jacob Holliman

Cadet
Joined
Nov 25, 2011
Messages
11
Re: johnson problem

have not changed primer bulb. they didn't have the rite size when i bought the fuel line or would have. it isn't dry rotted or anything tho. looks brand new. guess a possibility tho. wuts the vacuum switch do exactly? or the vapor pump i think its called, lil square diaphragm vacuum deal on top of the reservoir. anyone know alot about that stuff? called a mechanic today but he refused to give any friendly guidance after i bought a expensive fuel pump their yesterday. he wanted me to bring it in. no way i can swing that tho. fuel pump was bad enough. an im so used to being able to fix everything. this is driving me insane.
 
C

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: johnson problem

O-ring in quick disconnect fitting may be leaking, allowing air to suck IN yet still seal when pressure is applied by the primer bulb.

Many do away with all disconnect fittings and run hose directly to the pump, effectively removing a possible problem.
 
toddschubert

toddschubert

Chief Petty Officer
Joined
Sep 3, 2011
Messages
504
Re: johnson problem

Switch you taking about red and have a tire pump fitting? Fogger valve for injecting additives and winterizers evenly into all carbs/cyl. I think
 
B

Boss351

Cadet
Joined
Oct 12, 2011
Messages
10
Re: johnson problem

Had this happen with a buddy with a 120. His fuel bulb had a leak. We got another one and that took care of that.....Don't know if that is your issue but would suggest replacing the bulb if you haven't done so already.
 
toddschubert

toddschubert

Chief Petty Officer
Joined
Sep 3, 2011
Messages
504
Re: johnson problem

Bulbs usually come with adapter fittings like foe 3/8, 5/16 etc
 
J

Jacob Holliman

Cadet
Joined
Nov 25, 2011
Messages
11
Re: johnson problem

im not talkin bout the red primer selonoid deal. theirs a deal called a vacuum swicth an a vapor diaphram deal. an the primer buld the guy had was jus a 1/4. i am going to try that tho soon as im able.
 
You must log in or register to reply here.
Top