1990 Johnson 200 Fixed Jets?

[27E_20]

Guys,

Over the past few days, I have came across a multitude of problems with my engine (1990 Johnson 200GT, VJ200SLESE). I have discovered a stuck float in one of the carbs, and have been trying like hell to figure out the "coughing/sneezing" at idle speed issue. After some research on these forums, I have learned that the coughing/sneezing can be caused by the idle jets running too lean (amongst other things).

I think the best starting point is to rebuild the carbs (this will be my first experience, and I have no idea when the last time the were touched), but my service manual mentions something about them being "fixed". I am nowhere near an expert when it comes to carb cleaning/rebuilding, so is this typical with this model of engine, or is there some "sweet spot" adjustment for these jets? Or do I need to start looking elsewhere to troubleshoot the coughing/sneezing, like the throttle linkage?

Any advice for a novice?

 

[daselbee]

Re: 1990 Johnson 200 Fixed Jets?

Indeed, fixed jets, no adjustment other than changing to a different size. Do not do that first!!! Look for your problem elsewhere. The most overlooked and most likely cause of lean sneezing on these motors is the throttle plate. Look on the stbd side of each throttle plate, and you will see small metal core plug. It may have a metal plate held on with two small phillips screws. Depends on the model. Behind that, there are very very tiny holes that feed idle fuel through to the venturi bore, just at the butterflies. Those holes must be clean, as well as the rest of the idle circuit. Look up my many posts on the subject of looper carb cleaning. Another issue is that the link and sync must be perfect, particularly that all 6 butterflies MUST be closed all the way at idle. If one is bent, mis-adjusted, etc, and if ever so slightly open, it will usually lean sneeze. You can get it right by making sure everything is in "factory good" condition and adjustment. You will not need to change jet sizes, which is the approach many take. One other thing, those jets are on the front face of each carb, and they are air bleed jets, not fuel jets. They will not have any fuel varnish, gum, etc in them as they are never exposed to fuel. If they are clogged, the engine will run RICH at idle, not lean....see? If you want to try it, you can do this first.....it MIGHT, just MIGHT help your problems with lean sneeze. Get a can of spray carb cleaner with the straw, and put the straw directly in each of those fixed jets on the face of the carbs. Should have 12 of them, 2 per cyl/carb. With engine running, spray that carb cleaner directly in the jet; go around to each one, keep on doing it, use the whole can if you have to, and try to clean out any gum/varnish that way. The carb cleaner will go directly to those small holes I referred to above, in full concentration, and just MIGHT clean them out. Good luck. That is a tough motor to dial in.

 

[27E_20]

Re: 1990 Johnson 200 Fixed Jets?

Are these the plugs you are talking about?

 

[27E_20]

Re: 1990 Johnson 200 Fixed Jets?

Removing the throttle plates for cleaning means going through the sync and link procedures, right? The service manual outlines the procedure, but is there any problem areas I need to be aware of there?

Also, what is meant by a "looper series", or "v-loop engine"?

 

[daselbee]

Re: 1990 Johnson 200 Fixed Jets?

Yes those are the plugs. They went to a metal plate/gasket on later models. They are problematic to remove (read as PITA) and replace. The replacement core plugs come in each carb kit. Sooooo if it were me, I would do the spray carb cleaner trick first. OK, yes if the throttle plates come off, you need to do the link and sync. Two main reasons....sync operation between both sides; 1,3,5 and 2,4,6 by adjusting that link connector across the top, and sync operation between the two uppers and one lower on each side. Example sync between 1,3 and 5, because there is an adjustment between the carbs for 3 and 5. You will see it. It is a spring steel connection part with hex head screws. Looper and v-loop are the same term, and refers to the physics behind how the fuel/air charge enters the combustion chamber. A looper's fuel/air charge swirls in or "loops in". A crossflow's fuel/air charge enters the intake port and is deflected up by a large deflector dome built into the top of the piston. Loopers have basically flat pistons, crossflows have a large dome on top. Very significant difference. Main points on link and sync: Must have all butterflies closed at idle position, and all butterflies operate in exact sync with each other. Set idle stop and WOT stop screws such that the linkage travel is fixed and solid at both ends of the linkage travel. Then adjust idle timing for proper idle speed. Then set WOT timing stop screw. Your book will outline all this. Too much to type here.

 

[27E_20]

Re: 1990 Johnson 200 Fixed Jets?

Got it. Thanks for the help!

 

[daselbee]

Re: 1990 Johnson 200 Fixed Jets?

Looked at your pics again...and I see something that can change your process in debugging this. Look at the 11 o'clock position on the front of the carbs. Is there and adj. screw down in there? If so, you have other options. As I said, these carbs differ from model to model.

 

[27E_20]

Re: 1990 Johnson 200 Fixed Jets?

Here are a few facing the carbs:


Im not sure what you mean

 

[daselbee]

Re: 1990 Johnson 200 Fixed Jets?

You see the hole with the notch cutout on the side of it at about the 11:00 o'clock position? Is there an adjustment screw down in there deep? If so, you have a different beast regarding carb adjustments.

 

[daselbee]

Re: 1990 Johnson 200 Fixed Jets?

Also, the two brass orifices there at 9:00 and 8:00 o'clock are the fixed air bleeds that I suggest you spray carb cleaner thru with the engine running. Straw method....

 

[27E_20]

Re: 1990 Johnson 200 Fixed Jets?

You see the hole with the notch cutout on the side of it at about the 11:00 o'clock position? Is there an adjustment screw down in there deep? If so, you have a different beast regarding carb adjustments.

Ah, I see what you mean now. Looked through my pictures, zoomed in, cant see anything. The boats in storage so Ill have to verify tomorrow, but I do not see any mention of that in the manual. It only mentions changing the orifice size. The idle and intermediate orifices are visible on the outside (8 and 9 oclock), you have to remove the bowl drain screw to get to the high speed orifice. Ill give the straw method a try.

Thanks

 

[daselbee]

Re: 1990 Johnson 200 Fixed Jets?

OK no adjustment screw. Here is another trick to try while you use the carb spray. Using your palm, and while spraying in each fixed orifice, slap your hand/palm over the throat of the carb completely shutting off the air flowing through the venturi bore opening. Seal it off completely with your palm. Now what this does is create an instantaneous high vacuum in the venturi bore. It can and might cause any clogs to dislodge in the small passages that air flows thru that are separate and apart from the main venturi bore. You see what I mean? Even so, the carb cleaner will have a much stronger vacuum force sucking it thru those small passages. It might stall the motor, so be aware of that. If none of this works, and it is still lean sneezing, there are some other things to try before resorting to jet changing. Jet changing is the last thing you want to try, trust me. After all, it should run as designed.