HELP! 15 h.p. Johnson fuel problem

jpooter

Recruit
Joined
Jul 18, 2008
Messages
4
I have a 15hp 1974 Johnson that quit running. I purchased a repair manual and decided to try and fix it myself. I bought a spark tester and have good spark. when I did a fuel pump test, I found that no fuel is coming out of the hose between the pump and the carburator. If I pump the bulb it comes out, but when pulling the starter rope, nothing. I purchased a new fuel pump, and borrowed a different fuel hose from a friend. Still nothing comes out when turning the motor over. Compression is about 120 in both cylinders and the hole from the fuel pump to the cylinder is not plugged. I'm using a 6 gal plastic tank I bought last year and the vent is not plugged. I even tried it with cap off. Any help would be appreciated.
Joe
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,721
Re: HELP! 15 h.p. Johnson fuel problem

I have never investigated a fuel pump operation but i am pretty sure that you wont get much fuel out when pulling the engine over. You have proved that you can pump fuel through with the bulb so you should be able to fill the carb bowl initially.

You should at least then be able to start it and get it to run for a short while. If the fuel pump is not working you should be able to keep it running by pumping the bulb. If you cant then there is a problem elsewhere.
 

freddyray21

Commander
Joined
Jun 10, 2006
Messages
2,460
Re: HELP! 15 h.p. Johnson fuel problem

I agree the pump will not give you much there. the primer bulb will give you gas to the float to get it running then the pump will keep gas coming in. If you are not getting gas to the cylinders check the carb. could be something plugging the float valve.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: HELP! 15 h.p. Johnson fuel problem

Engine FAQs, "Outboard won't start".

Let us know what you find.
 

jpooter

Recruit
Joined
Jul 18, 2008
Messages
4
Re: HELP! 15 h.p. Johnson fuel problem

Thanks for the help. My manual says the fuel should squirt out. I've tried several times to start it and all I've gotten it to do is pop once or twice. I purchased a caburator kit when I bought the fuel pump so maybe I will go ahead and rebuild it first and go from there.
Joe
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: HELP! 15 h.p. Johnson fuel problem

Why should we give you advice if you simply ignore it, pooter?

You have already tried changing stuff and that didn't work.

Find out what is wrong first. Then fix it.
 

jpooter

Recruit
Joined
Jul 18, 2008
Messages
4
Re: HELP! 15 h.p. Johnson fuel problem

Man you guys are a rough crowd! I thought I was following your advice. I can't find the engine FAQ "engine won't start". I thought you guys were indicating I probably have a carb problem.
Joe
 

dajohnson53

Lieutenant Commander
Joined
Apr 28, 2004
Messages
1,627
Re: HELP! 15 h.p. Johnson fuel problem

Man you guys are a rough crowd! I thought I was following your advice. I can't find the engine FAQ "engine won't start". I thought you guys were indicating I probably have a carb problem. Joe
Joe, it's really not a rough crowd, but they did suggest you go to the FAQ for "engine won't start" and go through the steps to trouble shoot. Otherwise you're just skipping from possibiltiy to possibilty without focus, and it's hard to give advice.

Look for the FAQ here: http://forums.iboats.com/forumdisplay.php?f=4 Good luck
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,721
Re: HELP! 15 h.p. Johnson fuel problem

You have already tried changing stuff
I have noticed that chucking loads of new parts at a problem is quite a common practice. Fit loadsa new parts and when that fails find out what is really wrong, I assumed that was the American way. :) The British way would be to buy new parts as an absolutely last resort!
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: HELP! 15 h.p. Johnson fuel problem

You may want to check that the gasket between the fuel pump and the engine is in good shape and airtight.

BTW, it doesn't surprise me that one cannot find a thread called "Engine won't start" since it doesn't exist in the Engine FAQ. I know a lot of users get lost trying to find that link to the Engine FAQ forum, it is doubly confusing to have a FAQ link at the top of this page.

"....I can't find the engine FAQ "engine won't start. I thought you guys were indicating I probably have a carb problem.
Joe"
 

dimock44

Petty Officer 1st Class
Joined
Sep 7, 2007
Messages
275
Re: HELP! 15 h.p. Johnson fuel problem

I have noticed that chucking loads of new parts at a problem is quite a common practice. Fit loadsa new parts and when that fails find out what is really wrong, I assumed that was the American way. :) The British way would be to buy new parts as an absolutely last resort!

Not really the American way but I think more of a learning curve. Of course I just plain tight. out of the last 10 or so boats and probably 25 or so carbs I have only needed to buy I carb kit. I just hate to wait or go to the parts house. And like I said I am just plain tight.:D
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: HELP! 15 h.p. Johnson fuel problem

Did not suggest FAQs or "Engine won't start".

Suggested Engine FAQs, "Outboard won't start".

Truth is in the details. :)
 

kglade

Cadet
Joined
Jul 17, 2008
Messages
24
Re: HELP! 15 h.p. Johnson fuel problem

For what it's worth, I have a 1986 15 hp evinrude and when I pull the rope, gas spurts out of the hose from the pump to the carb.

Ken
 
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jpooter

Recruit
Joined
Jul 18, 2008
Messages
4
Re: HELP! 15 h.p. Johnson fuel problem

OK, I have tried squirting fuel both in the carb and directly into the cylinders. (I put the carb kit in because I already had bought it. Didn't see anything plugged inside the carb, but the spring clip was missing from the float needle?)1 small pop with about 30 pulles of the rope. I'm wondering if my spark is strong enough and consistant enough. When I attach my spark tester and turn it over, it does not spark on every pull. Every other and sometimes every third pull. Is that normal? I don't know if it's hot enough either. It jumps about 1/4" on the tester???
Joe
 
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