Fuel Problem - Help!

[Bereforest]

I have just purchased a 96 Bayliner with a 4.3 LX V6 Mercruiser. The boat had half a tank of fuel in which I topped up with another half tank of fresh fuel. After 40 minutes running we developed a bad misfire. On advice to check the fuel I have taken a sample which unfortunately smells heavily of varnish. I suspect the old fuel had sat for some time. I'm a bit reluctant to dump 40 odd gallons of fuel, but concious of not doing any further or long term damage to my engine. Are there any solutions that could allow me to burn off the old fuel without any lasting damage?

Also do I need to check / replace all fuel lines that may have developed a residue from now having pumped through this bad fuel?

Thanks.

 

[oops!]

Re: Fuel Problem - Help!

hi.....welcome to i boats...

bad/old fule is a real problem.....boat motors dont like it at all.

i would suggest to drain the tank and use the fuel a little bit a time in your car.

as far as the carb being varnished......you might want to try some carb claener thru it with new fuel.

HOWEVER......

i would check the electrical system for problems.....do you still have points and condenser?....if so check that first.

cheers
oops

 

[Bereforest]

Re: Fuel Problem - Help!

hi.....welcome to i boats...

bad/old fule is a real problem.....boat motors dont like it at all.

i would suggest to drain the tank and use the fuel a little bit a time in your car.

as far as the carb being varnished......you might want to try some carb claener thru it with new fuel.

HOWEVER......

i would check the electrical system for problems.....do you still have points and condenser?....if so check that first.

cheers
oops

Thanks oops. Really appreciate your advice. I have checked the electrical system and the coil is arcing out of the top casing. I have a new coil, leads, plugs, disy cap and rotor arm in the post to give the ignition a full service. Plus new fuel seperating filter.

Im concerned there may be some remnants of the varnish effect in the delivery pipes or even the tank. Is this common?

 

[Chris1956]

Re: Fuel Problem - Help!

As oops has advised drain the old gas out, filter and add it back in slowly with fresh fuel. Pull the gas line off and use the fuel pump to send some fresh gas thru the lines, and catch it in a clear container for inspection. Pull the fuel pickup on the tank and clean the screen and antisiphon valve.

 

[Silvertip]

Re: Fuel Problem - Help!

Do not run this fuel in your car. If it doesn't run well in the boat it will not run well in the car either and you run the risk of clogging fuel injectors, oxygen sensors, and other fuel related components that you may not have on your marine engine.