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1990 Johnson 4hp, carb not drawing in fuel.

mckibben23

New member
Hi Folks. I have a 1990 Johnson 4 hp that I bought recently (not running) with a suspected carburetor problem. Having fixed carbs previously I stripped this down, it looked very clean but I cleaned it again. The issue is that fuel is coming to the carb but not through it.

The float did not looked balanced and the pin was clipped through a hole in the arm of the float so I sorted that out, and got the float level. When I put it all back together and try to blow through the carb's fuel in-take it's blocked. When i remove the pin (from the seat in the carb bowl) I can blow fine through it.... the pin looks new, the float looks fine... is it possible that the seat for the pin is too tight? is there another way to adjust this/

Slow/Idle adjustment needle needs a new washer but I've put in one that should work okay, so I dont think that's a problem. Also when I spray gas into the carb it turns over ok... I've also confirmed that there is fuel coming to the hose attached to the carb's fuel intake. Any ideas? Thanks in advance.
 
One thing to note is when you turn on the fuel and shut it off, if you then remove the float bowl is it full of fuel? I notice normally fuel will start to come out as soon as I start to unscrew the bowl so I know it's full. If the bowl is filling with fuel and the main jet is clear then could it be the main needle running too lean? Just an idea. My fuel filter was clogged so had to strip it all to check it was all clear and my jet had gotten a bit of muck jammed in it.
 
One thing to note is when you turn on the fuel and shut it off, if you then remove the float bowl is it full of fuel? I notice normally fuel will start to come out as soon as I start to unscrew the bowl so I know it's full. If the bowl is filling with fuel and the main jet is clear then could it be the main needle running too lean? Just an idea. My fuel filter was clogged so had to strip it all to check it was all clear and my jet had gotten a bit of muck jammed in it.

Thanks. I checked that... no fuel at all. I'm thinking that the pin is getting stuck or maybe the seat for the pin is problematic... thanks
 
Thanks. I checked that... no fuel at all. I'm thinking that the pin is getting stuck or maybe the seat for the pin is problematic... thanks

When you say "pin" you are referring to the float needle valve? Part of #12 in the diagram below

If so make sure it is fitted pointed end into the seat and that it is clipped to the float arm with the little spring clip #14. This clip mikes sure that the needle is pulled off its seat when the float drops. Soft tipped needles are inclined to stick otherwise.

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Hi. apologies. thought I had replied. Yes I checked all of that and was aware that the needle can get stuck. the issue was on of the float not having enough space to drop the needle to the open position (when the float bowl was replaced)... i had to put a kind in the float arm to get it to work but it was very tricky to get this right while still maintaining as level a position as possible (with the carb upside down, as per instructions on youtube and so on).
 
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