Question about ethanol gas and 1957 big twin 35hp

[cocaptain5280]

I have a 1957 Evinrude Big Twin 35hp that worked great last season. Unfortunately, due to not having a reliable tow vehicle this year, it has remained in my garage (sad face).

The boat had to be rescued last year in November, and e10 gasoline with stabil was put into the tank to get it back. That gas was the last gas to run through the engine. We did let the engine run, pull the gas line, and let it die. But it is my thinking that some of the e10 gas is still in the motor and fuel lines.

I have since learned a great deal about these older motors, and now I know that ethanol gasoline should not be used in this older motor. Unfortunately, it has been in there for 10 months now...

What should I do? I can run the motor in my driveway with new (non-ethanol) gas this weekend. But what damage (if any) should I look for to see if the e10 fuel corroded any of the parts?

From my knowledge, the motor has been worked on recently over the last several years and had the older rubber fuel lines replaced, since all the inside parts look pretty new and clean. How much should I worry about the e10 sitting in the motor all this time, and is it really a big deal? What would you do?

Thanks

 

[Scott Danforth]

welcome aboard

fuel should never sit.

however if the fuel doesnt smell like varnish, top off the tank with fresh and go boating.

if it smells like varnish, then drain, clean your fuel system, then fill up with fresh fuel and go boating.

 

[cocaptain5280]

welcome aboard

fuel should never sit.

however if the fuel doesnt smell like varnish, top off the tank with fresh and go boating.

if it smells like varnish, then drain, clean your fuel system, then fill up with fresh fuel and go boating.

How do I drain and clean the fuel system?

Where and what damage should I look for due to old e10 sitting in there? I heard that ethanol ruins older components of these vintage motors, but I’m not sure where to look.

Thanks

 

[Scott Danforth]

the three biggest issues with ethanol

it breaks down faster than pure fuel
it acts as a solvent
some plastics do not get along with it

so are you saying the fuel smells like varnish. if so, you pour the crud from your tank and you fix your tank. you then pour the crud from your carb bowls and probably clean your carbs

 

[shrew]

You can pull the fuel line from the carb, drain the fuel line and then drain the carbs.

 

[mike_i]

If your boat runs top the tank off with fresh gas and go for it. Before I re powered my boat I had a 1987 Yamaha 175 2 stroke. A couple of times last year the boat sat for 5 to 6 months at a time with e10 gas. I did add sta bil, it started right up and ran just fine. After my fishing trip I topped the tank off with fresh gas and sta bil, the boat sat for several more months then once again started right up and ran fine. I think you'll be fine just top off the tank with fresh gas before you run it again. Good thing you have all new alcohol resistant hoses.

 

[superbenk]

If you pulled the fuel line & then ran the motor until it died then you shouldn’t have any fuel in the fuel system (at least beyond the point where you disconnected the fuel line). What’s left in the tank is a different matter that has been discussed above. Fuel lines & seals can have issues with the ethanol but it doesn’t sound like you ran it on ethanol much so I’d be surprised if anything is currently in a bad state.

 

[Sea Rider]

Are you using a portable or fixed under deck fuel tank ?

Happy Boating

 

[cocaptain5280]

Are you using a portable or fixed under deck fuel tank ?

Happy Boating

it is a portable tank

 

[cocaptain5280]

If you pulled the fuel line & then ran the motor until it died then you shouldn’t have any fuel in the fuel system (at least beyond the point where you disconnected the fuel line). What’s left in the tank is a different matter that has been discussed above. Fuel lines & seals can have issues with the ethanol but it doesn’t sound like you ran it on ethanol much so I’d be surprised if anything is currently in a bad state.

Correct. I did pull the fuel line and let the engine run until it died, but I still suspect that there is some residual ethanol gas coating the parts. I know the hoses are all newer, but worry about the parts I may not be aware of since I am new to boating.

I need to find a good video of how to drain and clean the carbs on this motor...

 

[superbenk]

My snow blower manual says to run it dry at the end of the season. This is to clear any gas from sitting in the system that could turn to varnish or phase separate into sludge. Anything left coating would evaporate pretty quickly & not be a problem in my opinion.

Only way way to really clean a carb is to pull it apart and make sure all the tiny orifices & passages are clean (compressed air and/or thin wire pushed through).

I personally think your engine’s fuel system is probably fine & I wouldn’t worry about it until you have reason to. I have yet to see ethenol gas phase separate but I did have problems with my snow blower last year when I didn’t heed the instructions. Never had an issue with any other gas thing I own.

Get some ethanol-free gas for piece of mind & go boating.

 

[JimS123]

My Big Twin is a 1953, with the pressurized tank. It sits on a restored woodie, and it only gets used once or twice a year.

I fill the tank full with 24:1, then take a boat ride a couple times in the Summer. In the last 20+ years all it has seen is E10. The fuel line from the tank to the motor was replaced and the carb rebuilt. Basically everything else is original.

I stabilize the gas when it is put in the tank. Last year due to weather it only had about 3 gal run thru her. So, this year some of that gas was maybe 2 years old.

The motor runs like a top and the gas looks fine.

Of course, garage kept and covered in between boat rides.

 

[cocaptain5280]

My Big Twin is a 1953, with the pressurized tank. It sits on a restored woodie, and it only gets used once or twice a year.

I fill the tank full with 24:1, then take a boat ride a couple times in the Summer. In the last 20+ years all it has seen is E10. The fuel line from the tank to the motor was replaced and the carb rebuilt. Basically everything else is original.

I stabilize the gas when it is put in the tank. Last year due to weather it only had about 3 gal run thru her. So, this year some of that gas was maybe 2 years old.

The motor runs like a top and the gas looks fine.

Of course, garage kept and covered in between boat rides.

This gives me hope!