1974 Johnson 9.9 quits while running

ErnieLearns · Aug 9, 2017

My 1974 Johnson 9.9 quits runs great at idle and full throttle and everywhere inbetween. Within the last week it has started to die suddenly as if its starved for fuel. It runs great at full throttle for 30 to 50 yards until it dies. It runs longer on idle until it dies. The motor will not start back up until you squeeze the bulb several times on the fuel line. The motor sounds great until it dies. There is one or two brief pauses before it quits almost as if the fuel line got disconnected. This made me think that it was a fuel delivery problem. I got a brand new fuel hose and bulb but the problem continues. I then changed the fuel filter but the problem continues. Any ideas?

Shaugh · Aug 9, 2017

Check the fuel pump.

Johnny · Aug 9, 2017

like Shaugh said: disconnect the fuel hose on the "outgo" side of the fuel pump
and connect a longer hose to it to flow into a clear plastic bottle.
crank the motor over. this will give you an idea of fuel flow.
also - if you are running SeaFoam in your gas, you may have an accumulation
of water in the bottom of the gas tank.
fuel delivery issues will drive you nuts before you finally find the problem.

oh - what brand of fuel hose and primer bulb did you purchase for replacement ???
how is the primer situated to the motor? it should hang in the vertical position
to maintain proper fuel flow. (photos of your fuel tank and hose might help).
did you change the "fuel filter" in the gas line or inside the fuel pump ?

.

ErnieLearns · Aug 10, 2017

So after ruling out the fuel hose (tank to the motor) and since I replaced the fuel pump and was still having problems, I took a spare gas tank I have and put new gas in it and mixed the oil and the motor seemed to work good with the earmuffs on. Today I took it to the water to test it again and the outboard worked flawlessly. So the issue was either with the fuel tank itself (probably 5 years old) or the brass fitting that connects to the fuel tank for the hose. I am going to rule out the gas which came from the same pump where I got my new gas. Thanks for everyone's input.

bassoreno · Aug 24, 2017

Johnny" if you are running SeaFoam in your gas said:
I never heard this before but I have a friend who always uses Seafoam and has frequent water in her gas issues... :shock:

Johnny · Aug 24, 2017

there ya go - SeaFoam is good if you run the motor ALL THE TIME.
like your automobiles - frequent use will not facilitate the moisture buildup.
if the motor sits over 30 days, that is when I have experienced this phenomenon.
out of a full six gallon tank with SeaFoam, I have siphoned 16 ounces of water.
many many MANY threads on this forum as well as all across the internet about
the pros and cons about gas additives.
tilt the gas tank on one end and let it sit overnight - then with clear plastic tubing,
put the end into the lowest corner and get a clear plastic water bottle and siphon into
the bottle until it is full - - - let that sit over night - then you will see where the problem lies.
Sta-Bil is a fuel "stabilizer" that is designed to keep fuel from going sour if you think it will sit for a few months.

I have switched to non-ethanol gas with no gas treatment additives UNLESS
I plan to run the whole six gallons in a weekend.

jus my Dos Centavos

Read, Understand and Follow the instructions on the label of all products you use.
Pay particular attention to the safety notes and heed the warnings accordingly.

.

LDUBS · Aug 24, 2017

Johnny said:
there ya go - SeaFoam is good if you run the motor ALL THE TIME.
like your automobiles - frequent use will not facilitate the moisture buildup.
if the motor sits over 30 days, that is when I have experienced this phenomenon.
out of a full six gallon tank with SeaFoam, I have siphoned 16 ounces of water.
many many MANY threads on this forum as well as all across the internet about
the pros and cons about gas additives.
tilt the gas tank on one end and let it sit overnight - then with clear plastic tubing,
put the end into the lowest corner and get a clear plastic water bottle and siphon into
the bottle until it is full - - - let that sit over night - then you will see where the problem lies.
Sta-Bil is a fuel "stabilizer" that is designed to keep fuel from going sour if you think it will sit for a few months.

I have switched to non-ethanol gas with no gas treatment additives UNLESS
I plan to run the whole six gallons in a weekend.

jus my Dos Centavos

Read, Understand and Follow the instructions on the label of all products you use.
Pay particular attention to the safety notes and heed the warnings accordingly.

.

I can't get ethanol free gaso anywhere in California -- wish I could just for peace of mind. I guess I'll just have to take the boat more often to keep gas from sitting too long. It is a tough job but someone has to do it. :LOL2:

1974 Johnson 9.9 quits while running

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