84 Johnson 35 not pulling fuel from carb

[Gregg P]

I have an 84 35hp Johnson, Fuel pump pumping, all new hoses, carb soaked for 3 days no blockages. It seems to not pull fuel from carb into engine. It has 122 & 121 compression, float bowl is full, bottom bowl jet is not stopped up. I can get it to start by holding hand over carb, then it pulls gas into intake and runs until thats gone and bowl is still fuel. Also has new reed valves. This thing is driving me insane. I'm familiar with 4 strokes but this is baffling. Any help we be appreciated.

 

[daselbee]

Double check the status of the nozzle gasket that seals the top of the fuel pickup tubes. Cracked, missing, smashed....the carb will not draw fuel if that gasket is damaged.

On the parts pages drawings it is ref# 7.

 

[Gregg P]

It was brand new with the carb kit, but I did think about doubling them up. That's should be the only place the fuel comes from right.

 

[daselbee]

Try it...won't hurt. But they are thick anyway. Maybe too thick to double up....

Yes, all fuel goes up that pair of tubes, one inside the other. Those tubes, especially the small one, are they clean?

 

[Tim Frank]

Double post

 

[Tim Frank]

Did you pull all the welch plugs and clean in behind them?

 

[Gregg P]

All of the orifices are clean, at least when I spray carb cleaner in it sprays out somewhere else. Thought about the plugs, but not sure what tool I need to knock them back in. But I have not pulled the plugs.

 

[Gregg P]

It was brand new with the carb kit, but I did think about doubling them up. That's should be the only place the fuel comes from right.

 

[Gregg P]

Double post

All the orifices are clean, but did not pull the welch plugs. not sure of what tool to put them back in with.

 

[Tim Frank]

All the orifices are clean,but did not pull the welch plugs

Then all orifices are NOT clean. It is a bit like trying to clean the bathroom....from the kitchen.... with the door closed.
You usually don't reuse them.
I am surprised that the kit that you bought did not have the plugs included.

 

[F_R]

You keep insisting that all orifices are clean. And so I have to believe you. But are you SURE??? Certainly sounds like the one in the bottom of the float bowl is dirty. Must be absolutely CLEAN with no trace of any dirt or varnish, etc.

 

[Gregg P]

That was my 1st inclination, but I can shine a light from the top and see light thru the jet with the drain plug removed.

 

[Gregg P]

You keep insisting that all orifices are clean. And so I have to believe you. But are you SURE??? Certainly sounds like the one in the bottom of the float bowl is dirty. Must be absolutely CLEAN with no trace of any dirt or varnish, etc.

That was my 1st inclination, but I can shine a light from the top and see light thru the jet with the drain plug removed.

 

[Tim Frank]

I have never trusted that the orifice plugs are clean unless I take them out and check....they also have to be the right size....and open to their full rated diameter.
Your jet is nominally 0.063"....a 1/16 drill bit should pass through snugly.

You don't say whether you've had this motor for a while and this is a new problem, or the motor is new to you and has had this problem since you acquired it.
The jet should have a number on it....63D....I've seen a few instances where used carbs were substituted by a well-intentioned DIY-er, but had the wrong jet size.
A 15HP carb on a 9.9.....30HP in a 35HP....etc. The carbs are often interchangeable, but the jets are not.

 

[Gregg P]

I bought this boat from the man that bought it new in 84. I started it up this year on the hose. Ran perfect till I took to the lake. Fired up 1st time left idling then it just died off. Then no fuel, I'll pulled the carb twice since then checking all the ports in the carb.

 

[oldcatamount]

Drill a small hole (1/8") through the Welch plugs being careful not to jam the drill bit through to hard. (There is a small pocket of space underneath the plug about 3/8" deep).Take a small punch and use it to pry out the plug. To re-install new plug, be sure it's sitting square with the casting (dome up), using a blunt punch, lightly rap it with a mallet to crush down the dome.

 

[Gregg P]

Thanks

 

[AlTn]

would add this to carb cleaning...note that the bowl to body gasket has 5 holes...4 are for the bowl screws and the 5th hole seals the passage way for fuel to flow up to the idling circuits...if you'll remove your idle mixture needle < count the number of turns out from a light seat first > and remove the core plug on top of the carb you can get at this passageway with spray carb cleaner and a round tiny brush..note of caution: be aware that this passage is small and you don't want to break anything off in it that you can't retrieve....

 

[Gregg P]

Thanks, but its clean.

 

[bonz_d]

Go back and check the float, float needle and the little clip that connects them together. If that clip is not put back on correctly the float will not open properly.