Float valve adjustment on Johnson 4

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paulwornell

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Having fuel problems with my J4 (circa 2000). Can anyone advise how to adjust the float valve. And out of curiosity can enyone enlighten me as the the function of the 'bladder' (little orange condom within a housing in the float chamber that seems to connect to a fuel line the runs to a connection on the block). Thanks in anticipation.
 
Generally carb floats are set so that the top of the float is parallel with the carb body when the valve just shuts.

Usually checked by tuning upside down.

Make sure the little clip is in position linking the foat arm to the needle. #14 in the DIAGRAM

I think I know what the bladder does but I'll check and report back.

but it connects to the integral tank doesnt it?

The hose from the crank case is surely the pulse line for the fuel pump.

tell us the model number and we can confirm the year.


In fact give noth America time to get sat in front of their computers and see HERE
 
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Vic, yes connects to internal tank. Model is 2000. Has internal tank and connection for external. The external tank connects to the upper body of the carb while the internal connects to the valve assembly on the side of the float chamber. The bladder locates in a chamber beneath a one way valve. All very confusing??
 
Id never thought about what the bladder did. I knew it was in Johnson/Evinrude carbs that accept two inlets so obviously something to do with that. I expect if I'd had an outboard like that I'd have figured it out by now!

No joy by asking the iBoats forum yet. I'll bump the question up if I dont get an answer by the end of today.
In the meantime I have asked on another outboard forum. We'll see if I get any joy there.

Anyway what are your problems?
 
I think I have now figured it out.

I think combined with the two one way valves (#31 in the diagram I gave a link to earlier) and using pressure/vacuum pulses from the crank case via the hose connection that it may be a small pump to pump fuel from the integral tank.

There is a separate diaphragm pump and filter in the fuel line between the remote tank connector and the carb to lift fuel from the remote tank.
 
Pink thing, top left?

Got to be a filter, hasn't it?

Back to the original question....

In 30 years of tinkering with various engines, large and small, I've yet to encounter one which needed the float level adjusting - plenty where the needle valve had worn or was full of dirt, but not anything that would be cured by adjusting the float level.

Suggest you get everything cleaned out and see if you still have a problem.

N.B. as already mentioned: Make sure that the needle valve is propely engaged on the float arm - on some carbs the float arm just rests on the end of the needle valve, but on others, there's a fork on the float arm which needs to hook around the end of the needle valve. It's not obvious without close examination.

What problems are you having?

Andy
 
Got to be a filter, hasn't it?
Click to expand...
No its a "bladder". There is a filter in the integral tank outlet and there is another on the fuel pump that pumps fuel from the remote tank
 
I think that makes sense.

I thank Vic for his analysis of the function of the bladder - which in combination with the tiny one way valve would achieve a pump action when fed from the internal tank. That must make the function of both components quite critical (as I always run on the internal tank).

Comment on float adjustment also welcomed. I will focus on valve function.

This all started because engine would start, if a little reluctantly, but only run at top revs and meanwhile fuel was seeping from the (new) rubber gasket between the float chamber and the carb body (hence question about float setting). I hasten to add that jets had already been out and cleaned and inline fuel filter changed. I had also tried running on the external tank with same result.

Back to the workshop.
 
It sounds as though you have a problem with the float valve not seating properly.
Try cleaning it but probably you'll need to replace it.
Watch out for that little clip I mentioned or you have the opposite problem ... the valve will stick shut

I reckon it is flooding slightly. Kills it at low revs but manages to keep going at high revs.
 
Like Vic said the needle valve is not seating properly
Most likely the 'seat' is ok but the needle could be worn, they kinda get a groove/lip.
Especially if rubber tipped.
Poor low speed running and difficult or temperamental starting would suggest a pilot jet/ air passage blockage.
As per Misterg
I have hardly ever had to adjust the float level on engines such as yours in 40 years !!!
 
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