1989 Johnson 20HP

[northwoodslivin]

Re: 1989 Johnson 20HP

Hey Guys,

WELL I finally got around to testing the new water pump I installed "success" She pisses like me drinkin beer

Problem though, she runs, but I dont know how to describe it "first off, could someone that knows tell me that when the motor is running do I need to pull out the primer at all? the description on the label confuses me"

I dont know how to describe it but its almost like it runs off and on on one cylinder some times. If I put it in gear and give it a bit of throttle or increase the low speed setting it will idle but I am not sure if it is 100%. I just ran a bit of decarbing stuff through it hoping that would help, then ran it out of the motor 10 or so minutes later and relplaced the plugs, same deal. So I sprayed the remaining 2/3rds of the can through the carb giving it throttle in forward and shut it down and I am going to let it sit a good 15 minutes "almost that time now"

I made sure the gap was correct and pushed on all the plugs and what not to make sure they we're tight. Other then that she runs good, I let the motor run for a good 15 minutes. Will do so now, will report back, in the mean time if anyone has any suggestions?
PS plugs and coils look like new!

 

[northwoodslivin]

Re: 1989 Johnson 20HP

Well... Finished decarbing, noticed some black stuff coming out of the little relief holes, other then that it runs slightly better. has that little sneeze that shakes the motor and gives it a semi grougy acceleration.

For instance, when I put it in forward gear and rev to about 5k and let it come back down to idle, it will give off "not always" a little sneeze, the idle will shoot down for a split second and a little puff of exhaust comes out.. What could this be? I hope it is nothing serious :S

 

[ezmobee]

Re: 1989 Johnson 20HP

Dirty carb most likely.

 

[northwoodslivin]

Re: 1989 Johnson 20HP

Dirty carb most likely.

Ya.. I was starting to think that as the culprit myself... hmm. Will that stable marine stuff that you put in the gas clean it up you think? I really dont want to rip the carb apart

 

[northwoodslivin]

Re: 1989 Johnson 20HP

Should mention, I used the Mercury Power Tune stuff today to decarb it. Next time I am in town I am going to pick up a can of Sea Foam as I found out that NAPA in town now stocks it and dump a whole bottle in a fresh tank of gas and see how that does. Hopfully it is just gummed up from having sat so long, plus I let the gas I used to try it in the winter time sit in the carb until now so that does not help either.

Hopefully that will take care of it, if not. I will rebuild it but something tells me Sea Foam might be my easy ticket

 

[ezmobee]

Re: 1989 Johnson 20HP

From what I understand...SeaFoam (and other additives) do nothing to clean a dirty or clogged carb. They can only help keep a clean carb clean.

I have to rebuild the carbs on my 90. I'm very afraid

 

[bob johnson]

Re: 1989 Johnson 20HP

was at the mechanics today asking about picking up some seafoam...he showed me the OM factory stuff...that screws onto a VALVE on the primer..

he said that stuff can eat a hole in a piston in not used properly...very caustic, or something like that....wasnt exactly sure why ...

he said onloy a guy who really knows what he is doing should use that stuff..

he sold me some additive that goes in the gas...doesnt smoke...1 oz per 8 gallons of gas...he says use it often and it helps decarb constantly

bob

 

[jbjennings]

Re: 1989 Johnson 20HP

Should mention, I used the Mercury Power Tune stuff today to decarb it. Next time I am in town I am going to pick up a can of Sea Foam as I found out that NAPA in town now stocks it and dump a whole bottle in a fresh tank of gas and see how that does. Hopfully it is just gummed up from having sat so long, plus I let the gas I used to try it in the winter time sit in the carb until now so that does not help either.

Hopefully that will take care of it, if not. I will rebuild it but something tells me Sea Foam might be my easy ticket

There's no way to get around cleaning your carburetor when it's gummed up. All the sea foam and such will do for your carb is keep it from getting gummed up. Squirting sea foam into the carb. throat is absolutely pointless unless you're going for decarbonizing the cylinders. It won't clean the carb.
It's totally simple to clean it, so don't be afraid to do it. Just make darned sure that you don't break off the plastic nipples and stuff that the tiny fuel lines go on the primer body. It's really frail and if it's cold outside they will almost break if you look at them funny. The carb itself is a really simple design and particularly easy to rebuild from my experience. You might even get away with not buying a carb rebuild kit. Just clean out all the tiny passages and stuff with carb. cleaner---wear eye protection!
If it's surging like you describe, you could very easily be losing spark intermittently to a cylinder due to a bad coil, etc. Just because they LOOK good means nothing. Run it in the dark to look for arcing from cracks in insulation, etc.
Good luck and glad to hear she's staying cool now!
JBJ

 

[northwoodslivin]

Re: 1989 Johnson 20HP

JBJ Don't say that! I hope none of the coils are bad

I totally realize that spraying "anything" in a carb throat will do nothing in the means of cleaning the carb, what I had wanted to do with the sea foam, was to add a can to a fresh tank of gas and run it through the carb/motor that way.

Well... I guess I am gonna have to pick up some carb cleaner and rip her apart, will be the first carb I have ever done myself. It was usually my father that did all that for me when I was a young kid with my dirt bikes etc. He told me I was crazy for attempting to take it apart and use an additive in the gas Hmm, I should probably order a rebuild kit huh? I know I could probably get away with using some of the stuff, but I hear that you have to replace the gasket on the manifold if you remove the carb, and of course the needle jet rubber ends may be worn.

 

[northwoodslivin]

Re: 1989 Johnson 20HP

just an update, cleaned the carb and now she runs like a champ!

 

[northwoodslivin]

Re: 1989 Johnson 20HP

Another update.

Well, I finally got around to testing the boat out with the motor yesterday out on my lake. I am back to square one, I can start it, and most of the time it will idle ok. If I put it in gear and start going slowly it will sneeze/cough when doing so a big plume of smoke will come up through the water. I am taking it that I reclogged the idle jet again. "Must get an inline fuel filter! can I use an automotive fuel filter? If so I am taking it I should get a big one?"

Secondly, when I cleaned the carb, there was this little silicone cap that went over the idle jet screw, I forgot to put this back in, would this cause a problem/suck air with out it in or does that cap just prevent the jet from turning out? Thing is, after I cleaned the carb, I tested the motor on muffs and it ran amazing and idled very nice. Also, the motor, at WOT will run ok but I am finding that it isnt no where near as fast as I thought it would be? I forgot to bring my GPS but I am guessing it is going around 8-10MPH? Which I would tend to think is nowhere near as fast as it could be, what could be the problem there? With just myself in the boat it will get on plane just fine, but with my father in the front it wont, but maybe I need to put the transom bracket pin back another notch?

Could really use some advice fellas.
PS, from what I am reading, could a link and sync be my problem for the speed? when the motor is WOT, it does not cough or anything, which leads me to believe my idle jet has some gunk in it again.

So strange, ran beautiful when I cleaned the carb, ran the carb dry, put it away for a few weeks, brought the boat to the lake and it is running like it was before I cleaned it

Help!

 

[northwoodslivin]

Re: 1989 Johnson 20HP

Also should mention, if I let the idle get to low it will sneeze and stall leaving a plume of smoke rising up in the water, surely sounds like a dirty idle jet again huh? or if I give it just a bit more throttle, it will keep going but will sneeze once in a while, leaving that plume of smoke rising up. I docked the boat and made sure the idle jet was 1 1/2 turns out from snug just to make sure, what about that silicone cap, does that need to go back in there? or can I put a blob of marine silicone in there in place of the old one? NEEDED? or not?

This is not really the issue I am asking, the issue is the power seems to not be there, has the speed of a 9.9 it seems?

hope to get this resolved so I can get back out on the lake!

 

[northwoodslivin]

Re: 1989 Johnson 20HP

Anyone?

 

[northwoodslivin]

Re: 1989 Johnson 20HP

Well I bought a fuel filter for marine use and will clean the carb again and see how that works.

 

[northwoodslivin]

Re: 1989 Johnson 20HP

Just an update.

I have come a long way with this motor since I have last posted.

For some reason my carb kept getting plugged up, I blamed it on the gas, bought a good marine fuel filter, same thing kept happening. Then I did some research on Ethanol and what it can do to older fuel lines. Well sure enough, one of my fuel lines was starting to get eaten by the Ethanol in the gas. I ended up replacing all of the lines. All was well, till about 15 minutes on the water then that darn cough/sneeze happened again, frustrated I ripped the carb off AGAIN, but this time I ended up pulling the two orifice plugs, sure enough there was 3 specks of fuel line rubber in the one passage. Put it all back together and now it runs like a champ. BUT!

All the times I had it out I always thought something was not right, for example. At WOT with my father up front I couldn't even get my boat to plane out. Well guess what. Yesterday I fired up the motor as I haven't had the boat out in over a month so I wanted to cycle the gas in the carb. And for the heck of it, I looked into the carb throat when reving the motor and noticed the butterfly at WOT was hardly even opening! Well, I adjusted it now so it is almost flat when WOT, wow! what a difference, it rev's way higher now, I am so anxious to get out on the water to try

Boy has this motor been a headache from day one, but all my problems are finally taken care of.

One final question though. It is to my understanding that the idle jet adjustment should be 1.5 turns out from snug correct? I let the motor warm up, put it in gear and adjusted it but I feel it may still be running a tad rich, because when I shut it off you can see unburnt fuel coming out of the one relief hole above the cavitation plate. Should it be less? I was going a little more and a little less when adjusting it trying to get the smoothest idle. It wont stall or anything but does shake a little when idleing, just curious as to what to do there... I also have seafoam in the gas, I added way to much "smokessssss lol"

 

[bob johnson]

Re: 1989 Johnson 20HP

your troubles are the exact reason many people say that if it your own motor, the first thing to do is go buy a factory manual...

it can clear up most issues and it does it methodically..or it guides you through it anyway.

second is all the settings needs...they are there in the book!!!!

as for the gas...when you shut downm the motor the spark is killed but the rpms wind down somewhat and as such the last few strokes brough gas in that didnt get burned....and maybe have also got pushed out...i wouldnt worry too much about the residue after you stop the motor.

you should err on the rich side as opposed to the lean side...lean give you more power, but burns thinghs up if too lean...

rich isnt as destructive

good luck

bob

 

[northwoodslivin]

Re: 1989 Johnson 20HP

Thanks Bob, I appreciate your reply. I do have a manual for it, well it is .PDF and covers so many motors and is not very detailed to my exact motor. Just wanted to make sure.

Thanks!

 

[Cofe]

Re: 1989 Johnson 20HP

Thanks for reporting back northwoodslivin!

Just goes to show what new rubber gas lines can do.

Heck grain alcohol and old rubber got me in trouble before.

Good to see you got your motor going! Now to catch fish

 

[northwoodslivin]

Re: 1989 Johnson 20HP

I guess these we're the original lines! They looked like new on the out side though lol. The ones I bought are approved for ethanol so I am good to go. What a difference! Yep, hope to get her out and do some fishing this weekend or possibly tonight, been having some health problems that have been keeping me down and out. Very anxious to try the motor out now, she's gonna fly

Cheers and tight lines!

 

[northwoodslivin]

Re: 1989 Johnson 20HP

Hey guys,


Sadly, I just finally got around to testing the motor out "wow it hauls butt now!!!"

I have a question, the relief/upper ports that expel water when the thermostat opens and closes, is water supposed to always be coming out of those two big ports or only when the thermostat opens? I have a feeling my thermstat is stuck open because from the second I start my motor it is expelling water from those two ports and does not stop?? I watched a guy that has the exact same year and size motor as mine on youtube and his wasn't expelling water then opened up and you could see it shooting out of those two ports. Could anyone confirm that for me? it is not a mist it is coming out but not SHOOTING out? but not gushing out either, like when you turn on a tap a bit

Motor runs much much better, I took it out to a big deep lake tonight so I could test it WOT. It runs amazing WOT, but when I back off to a little bit above idle I get the odd backfire still, I am wondering if this could be in conjunction with my plugs gaped at .40 "intended to basically only troll/slight above that mainly with this motor" and my thermostat that could be stuck open?

I would tend to think if it is stuck open this could be a problem as my motor would not be getting up to operating temp?

Sorry, but my manual mentions nothing of this so this is why I am coming here to ask the pros

Thank you much for your help in advance! "If it sounds like my thermostat is shot I will go pick up a new one tomorrow"

ETA: I should also mention that before I took the motor out on the lake today, I ran it on the muffs for approx 5 minutes with the hood off, I was feeling the cylinders and they we're cold after 5 minutes, before I shut it off I felt them again and they were room temp warm "ever so slightly warm" and the water coming out of the tell tale and exhaust baffle is cold, not even the slightest bit warm.