1992 40 hp johnson wont stay running

[stump01]

I recently bought a used boat with a 40 johnson on it. I had it out a couple of times and noticed that the motor ran rough at slow speed. I ran some seafom through it and didn't help. so i tried to adjust the carbs I turned them in all the way and backed them out 1 1/2 turns this is were they were set originaly. now the motor wont stay running, it seams like its not getting enough gas. any ideas on what happened?

 

[seaswirl71]

Re: 1992 40 hp johnson wont stay running

have you verified the fuel pump is working correctly? tried pumping primer to see if it will stay running?

 

[stump01]

Re: 1992 40 hp johnson wont stay running

yeah i tried to pump the blub and that didn't work.

 

[seaswirl71]

Re: 1992 40 hp johnson wont stay running

if the fuel pump is working and you have good spark either the carbs are dirty and need a rebuild or they aren't adjusted right, that vintage i bet the carbs are all clogged up, but i AM STILL RATHER NEW TO outboards myself

 

[stump01]

Re: 1992 40 hp johnson wont stay running

the thing is that it ran o.k (a little rough at idle) before I turned the carb adjustment screws all the way in and back them out to the original position and now it runs really rough and wont idle at all. Pumping the bulb does not do anything, but pumping the primer will keep it running.

 

[tx1961whaler]

Re: 1992 40 hp johnson wont stay running

but pumping the primer will keep it running.

The carbs need to be thoroughly cleaned.
Instructions are here:
http://forums.iboats.com/showthread.php?t=244013

 

[Thirsty Turtle]

Re: 1992 40 hp johnson wont stay running

Have you checked the plugs to make sure that they were not fouled. If you adjusted it too rich you may have fouled them out.

 

[stump01]

Re: 1992 40 hp johnson wont stay running

I did check the plugs they seamed ok the strange thing about this is that when I turned everything back to the original position it didn't run right.

 

[seaswirl71]

Re: 1992 40 hp johnson wont stay running

there are adjustment procedures to set the low speed needles, I think you start at 1 1/2 turns out and adjust them with engine running until smoothest operation is achieved, well at least thats how my 1970 60hp was done.

 

[tashasdaddy]

Re: 1992 40 hp johnson wont stay running

your jets are #9 and #3, all you did was mess with the air mixture. http://shop2.evinrude.com/ext/index.aspx?s1=bf6ad09c53cead335fcfd8a6471c0f7f

 

[Steveb353]

Re: 1992 40 hp johnson wont stay running

Hi, Just went through the carbs. on my J40ELENM..The idle screw settings are 2 1/2 turns out..You said your settings were 1 1/2 turns..My manual has a notation footnote explaining this..Just wondering if this could be your problem.
Regards.

 

[Bugman1]

Re: 1992 40 hp johnson wont stay running

Hi, Just went through the carbs. on my J40ELENM..The idle screw settings are 2 1/2 turns out..You said your settings were 1 1/2 turns..My manual has a notation footnote explaining this..Just wondering if this could be your problem.
Regards.

Remember that the fuel/air mixture settings you are tinkering with are for NEW MOTORS/FACTORY SETTINGS. Unless you have rebuilt your motor to OEM specs, those settings are "guidlines", work around them.

Bug.

 

[crxess]

Re: 1992 40 hp johnson wont stay running

In answer to your original question.
If your settings Were 1-1/2 turns out and are now 1-1/2 turns. Turning the needles in probably packed down debris in the tiny openings cutting off air flow.
Crab rebuild it the least expensive way to try and correct your idle problem.

You can adjust all day, but if they are restricted or blocked it is not going to run right.