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1983 Johnson 75HP

S

streamer

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"Just rebuilt completely my mo

"Just rebuilt completely my motor. Cranks and runs fine except after being run a while and I stop for a while then try to start and it won't. Seems flooded. I have gone thru carbs changed all fuel lines, replace tank line. The tank is 40 years old. I am suspicious of the sending unit on the tank but I do not leave the tank hooked up to the motor to rule it out. I took apart the fuel pump and bought a new kit for it. Unfortunately it
does not work due OMC changing the old parts over to a slightly smaller pump. The Johnson dealer I buy my parts from said they had seen this problem before on pumps this age. Inspection of the pump parts really shows no problem just replacing gaskets etc to rule this part out. Cranks fine if the motor sits for a long time. Have check fire to plugs in the dark and all three are bright blue
coming off the plugs. Help what am I missing."
 
"Seems flooded ? Check the pl

"Seems flooded ? Check the plugs next time, tap onto your palm get anything ?"
 
"Yes it has to be flooded but

"Yes it has to be flooded but why? I don't squeeze the bulb, don't even hook up the line until just
before starting. I have changed the all the plugs 2 times to rule them out but they looked fine. All symptoms point to flood but why? Both my tanks are original OMC oval red tanks. The sending units cost
$150.00 dollars. One of mine if there is any pressure in the tank, like from being in the sun
then it will drip from the connection. I just place a small piece of fuel line with a bolt in it attached to an extra fuel supply line connector to just stop it from dripping. I do not use tank now. I have tried to rule out anything which could be causing flooding but have not found the fix yet."
 
"[b] if there is any pressure

" if there is any pressure in the tank, like from being in the sun

Could be, do you have your Vent on the tank open? you should when running.

Carb flooding is either the floats are set to high or the idle mixture screws are set to rich or the fuel pump diaphram has tiny pin holes.

What does the fuel look like when you put it in a jar ? is it orange? if so then there is rust in your tank (happened to me but not with outboard tnak)"
 
OMC tanks do not have a vent t

OMC tanks do not have a vent they are a closed system. I checked the gas tanks before using and they were good except for the sending unit on one.
No mixture or any other adjustment other than linkage on these type carbs. I suspect the fuel pump diaphram. but am still looking for a the reason.
 
"Should have a little thumb sc

"Should have a little thumb screw on the top of the cap, that's the vent. Unless you are using a pre-56 OMC tank, those caps dont have vents.

The little cap thumbscrew is the vent(white square area), granted this is a newer tank, you could open your cap to releive the pressure.

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