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Discussion Starter · #1 ·
Can anyone give me some advice on cleaning carbs for a Johnson 150 outboard. Does this require removal, disassemby? How much time is involved?
 

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Franks Seaswirl said:
Can anyone give me some advice on cleaning carbs for a Johnson 150 outboard. Does this require removal, disassemby? How much time is involved?
Hello

You should have a connection on your motor that you can hook up a can of decarb to. It looks like a Valve stem.

If my memory serves me right you release while the engine is running, one blast for each cylinder then give it another longer blast. Shut the motor off and wait about 2 hours, then fire her up at a fast idle. Or better yet do this procedure in the water.

Misty Lady
 

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MISTYLADY2 said:
Hello

You should have a connection on your motor that you can hook up a can of decarb to. It looks like a Valve stem.

If my memory serves me right you release while the engine is running, one blast for each cylinder then give it another longer blast. Shut the motor off and wait about 2 hours, then fire her up at a fast idle. Or better yet do this procedure in the water.

Misty Lady
Decarboning the engine will not clean the carbs if they need it. There is no juice that will clean a carb without first disassembling it. And you don't want to burn an automotive type carb cleaner thru your outboard. Dirt in a carb has to be removed manually. Gum/varnish, use a carb cleaner and small jet brushes to clean the jets and passage ways.

Frank, go to Barnacle Bills web site and get the Bomb parts diagram for those carbs. Do one at a time and lay out the parts on clean paper in front of you. Don't be afraid to take pictures(digital camera) of the carb linkages before you start pulling carbs off the engine. Once you do two you'll wonder what you were worried about. Just take your time and make sure every little crevis, hole, valve and passageway is clean. Becareful not to bend the float arms or you'll need the gauge to reset them.

What is the engine doing that you think the carbs need cleaned? Do you have a fuel filter(Racor) between the tank and the engine? Have you changed the white plastic inline filter under the engine cover? If you clean the carbs change all the filters.


This brings up a good point of having a couple of disassembled carbs on hand for this Outboard Maintence Seminar.
 

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Discussion Starter · #5 ·
Dunk,

Thanks for the advice. It was running rough at idle last year. Ran ok at higher RPM's. I do need to change the water separator as you mentioned.

My thinking was cleaning the carbs would at least eliminate that as a source of causing it to run rough. And its never been done and this is a 2000 Johnson OB.

Frank
 

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Start with the basics before you dig into the carbs. Take a fuel sample if it looks good, I doubt you would have to remove the carbs. The carbs on that engine are prone to warping and causing air and fuel leaks. Before you do anything take a fuel sample, compression test the engine, and check each cylinder for spark with the engine running. If all of that looks good remove the air box and start the engine -- prime the primer bulb while the engine is running and look for leaks on the vapor separator and the individual carbs. Also be sure to look for fuel spewing out of any one of the carbs at a particular rpm range, which would tell you that you have a float or air leak at the float bowl. Don't over look the obvious and jump into the more difficult things. If you decide to remove and rebuild the carbs , get a manual and perform the proper sync and link after installing the carbs back on. If not you could actually make the engine run worse.
 
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