A fuel question... I did a carburetor 'no no'.

[Ki Ki]

Hello All, terrific forums here. My first post, but I plan to stick around a long time.

Anyways, I have an old Evinrude / Johnson 2 cylinder motor. I think I did the ultimate 'fuel' no no. Basically, I bought a winterized boat from a guy that sat for 2 seasons. I think what he did was add about 3 gallons of 'new fuel' to 3 gallons of 2 season old fuel. Boat was doing well, with a cold start. Now it has gotten to the point where it won't go into gear without stalling, except with a water hose attached.

Basically, if I ran this old gas through the motor could the carbs have got gummed up that quick? It's in the shop and the compression is great. The carbs are going to get rebuilt. Question is, I still have a small percentage of that old gas mixed in the tank. How do I safely discard this?

I noticed too that the engine was shaking at lower speeds like it was starving for fuel.

 

[Ki Ki]

Re: A fuel question... I did a carburetor 'no no'.

I should ask this too... By now, I'd say after running most of it out that the ratio of new gas to old gas is about 4 parts new, 1 part old in a 6 gallon tank. After the carb cleaning/ rebuild would that ratio still be okay to run that tank or should I start with a fresh tank of fuel?

 

[TerryMSU]

Re: A fuel question... I did a carburetor 'no no'.

Hello All, terrific forums here. My first post, but I plan to stick around a long time.

Anyways, I have an old Evinrude / Johnson 2 cylinder motor. I think I did the ultimate 'fuel' no no. Basically, I bought a winterized boat from a guy that sat for 2 seasons. I think what he did was add about 3 gallons of 'new fuel' to 3 gallons of 2 season old fuel. Boat was doing well, with a cold start. Now it has gotten to the point where it won't go into gear without stalling, except with a water hose attached.

Basically, if I ran this old gas through the motor could the carbs have got gummed up that quick? It's in the shop and the compression is great. The carbs are going to get rebuilt. Question is, I still have a small percentage of that old gas mixed in the tank. How do I safely discard this?

I noticed too that the engine was shaking at lower speeds like it was starving for fuel.

So if I understand correctly, you are running the motor with the lower unit dry? That is a big no-no. The water pump has an impeller made of hard rubber. It needs the water to keep it lubricated so it won't burn up. Do not run it without the hose connected. I assume that you are talking about running it on the "muffs".


TerryMSU

 

[RWilson2526]

Re: A fuel question... I did a carburetor 'no no'.

My opinion is that it may have been a coincidence and 2 year old gas shouldnt have any lasting effects on your carburetors...but if its only a 6 gallon gas tank just burn it in your lawn mower and start fresh to be sure.

 

[Ki Ki]

Re: A fuel question... I did a carburetor 'no no'.

I ran it on ear muffs. Should I replace the fuel tank entirely since it sat for two years after the carb rebuild? Or should I completely run out the one tank that has a percentage of two year old fuel.

 

[rbh]

Re: A fuel question... I did a carburetor 'no no'.

I ran it on ear muffs. Should I replace the fuel tank entirely since it sat for two years after the carb rebuild? Or should I completely run out the one tank that has a percentage of two year old fuel.

All metal tank's will get some form of crud on the sides and bottom over time.
I have in past taken a couple of medium sized marbles and dropped them in to a tank filled with
"varsol"
Remember gas and possible sparks do not mix
put it in the back of the truck and drove it around for a week, the marbles will break up most of the crud.
Swish it around then dump out the residue, repeat till fairly clean.

 

[northernmerc]

Re: A fuel question... I did a carburetor 'no no'.

Mixing a bit of old fuel with a larger quantity of newer fuel usually works out OK. If you have crud in the tank that built up over the years, that's another matter. Pour the gas out of the tank into a gas can, through a funnel with a screen filter. See what collects on the filter. That - and a visual inspection of the inside of the tank - will give you a better indication of whether or not you have a fuel/tank problem.

 

[Ki Ki]

Re: A fuel question... I did a carburetor 'no no'.

Mixing a bit of old fuel with a larger quantity of newer fuel usually works out OK. If you have crud in the tank that built up over the years, that's another matter. Pour the gas out of the tank into a gas can, through a funnel with a screen filter. See what collects on the filter. That - and a visual inspection of the inside of the tank - will give you a better indication of whether or not you have a fuel/tank problem.

Thanks all. It's a modern plastic tank that was properly winterized, but it still wasn't ran for 2 years. I think it's what fouled my carbs, which are now being rebuilt.

It was odd, boat ran okay, but a bit sputtery from the get go after purchase. Expected it for a 1970s engine. It then eventually went form a cold start, to stalling shifting into gear. Sounds very fuel related. I added stabil to the tank and filled the tank with new gas. So if there is old fuel after the carb rebuild I'd guess it's less than 15% of the 6 gallon tank.

 

[Home Cookin']

Re: A fuel question... I did a carburetor 'no no'.

dump the old gas (not literally) not worht saving at the risk of a follow-up carb job. Phase seperated fuel is bad stuff, and it's still there when you add new gas. It is deceptive to think new gas dillutes bad gas when the bad stuff is all at the bottom at the pick-up.
Stabilizer won't restore it

it's only 6 gallons; a lot of people are dealing with 100.

 

[Ki Ki]

Re: A fuel question... I did a carburetor 'no no'.

dump the old gas (not literally) not worht saving at the risk of a follow-up carb job. Phase seperated fuel is bad stuff, and it's still there when you add new gas. It is deceptive to think new gas dillutes bad gas when the bad stuff is all at the bottom at the pick-up.
Stabilizer won't restore it

it's only 6 gallons; a lot of people are dealing with 100.

Great point, I guess it'll become my weed wacker fuel now or lawn mower!

 

[tmcalavy]

Re: A fuel question... I did a carburetor 'no no'.

Check the fuel lines on that motor. If they are/look original, replace them. The gas we get these days is laced with ethanol and that will degrade old lines not made with ethanol in mind...the ethanol will eat the old lines from the inside out and the gunk goes into the carb(s).
So, how old is old? Modern muffs/flushing attachments aren't compatible with older motors, as previously noted by another poster. Run it in a tub/barrel and check for cooling water discharge...may need to now replace the impeller.