Timing issue help

[Thompsoncustom]

I have a 1990 johnson j20cresb 20hp and I think i'm having some timing issues, got this motor with some of the throttle linkage missing and a bent prop. Replace prop and bracket and than it would die on acceleration and coughs at idle speeds. Rebuild carb and fuel pump and running a clear fuel line from the pump to the carb to check for air.

Now the motor runs good at high speed for my little 30 sec test on the river but still coughs bad at idle and when decelerating. I'm thinking it's running lean so I haven't had it to max speed more than twice so far for 30 secs as I don't want to burn anything up.

I have not done a link and sync as I am not 100% sure on how to do it yet so if anyone has some pointer what the best way to do it on a manual pull start that would be great. I do have a timing light.

You can overcome the coughing at idle a little if you pull the choke in and out just a little about every sec or 2. Idle speed screw does nothing.

 

[Thompsoncustom]

Also if anyone knows what the timing needs to be set at that would be a great help

 

[AlTn]

no timing to set on that motor...keep opening the idle mixture needle a 1/4 turn at a time until it has an effect on that idle < if it never seems to have an effect then you still have some idle circuit cleaning to do or you have an air leak into the carb/intake somewhere >...once you notice that the motor seems to load up at idle then the mixture is too rich and you needle to lean it out by turning the fuel mixture needle in 1/8 turn at a time until you achieve the idle you want...would recommend leroy's ramblings 9.9/15 hp. johnson/evinrude maintenance and repair website to you as far as link/sync info and other information on this series

 

[Tim Frank]

An OEM manual is a great accessory.

 

[Bosunsmate]

id think that the carb still has a blockage, a soft small wire and compressed carb cleaner has to go down and out all tiny passages, just doing jets wont ever do it

 

[oldboat1]

think the clues are use of the choke to keep it running at idle, and no response in adjusting the idle speed screw. would suggest pulling the carb off again, and working on the idle system at the top. Find a blow up of the carb online, and get a kit if you haven't done that. There appear to be a couple of core plugs up there (I call them expansion plugs). They need to come out, and will need replacements. There is also an orifice plug up there (front), and of course the l.s. needle you have been trying to adjust.

If it were mine, I would pull it apart and soak the upper part of the carb, then clean out all passages with a fine wire and compressed air or carb cleaner. While at it, of course, would disassemble and soak the rest as well -- same cleaning process. But think it's the idle system that needs work. May find the motor runs like new.

 

[Thompsoncustom]

Well that make sense I seen there was timing marks on the flywheel but didn't see how to adjust it.

I've had those smash plugs out and cleaned everything with a wire but maybe a couple day acetone soak is what it needs.

What are some common places for air weaks on these motors?

 

[oldboat1]

sounds like you did cover the l.s. passages. There is the orifice plug on the front. might blow that out and maybe run a small wire through it (frowned on). It's kind of a complex model, as carbs go. I think air leaks aren't usually an issue (could be wrong), but air venting -- a reason for opening up and cleaning every nook and cranny. Yeah, soaking is the way to go, but if you opened up those passages and sprayed them out, that might do the job.

Still, the symptoms seem to say the idle system has a blockage somewhere.....

(edit. can't help on those flywheel marks, offhand. If you have a timing light, you could hook it up and test using those marks, just for grins.)

 

[Thompsoncustom]

Well carb is submurged in acetone I'll leave it there for a couple days and than blow it out. Used some wd-40 to look for airleaks another the intake manifold but didn't find anything.