Re: 1979 evenrude fuel fillter question
A couple of things: 1. The original factory fuel hoses inside the 1979 cowling are not compatible with today's ethanol fuels. If you run ethanol blend gas through it, you may eventually find small black bits inside the jets of the carbs. (Small pcs of fuel hose.) A fuel restriction can run the engine lean-potentially a real problem. You can go to a Bombardier dealer and buy all the same fuel hose part numbers again. The new hoses will be compliant with 2011 fuels. (Those internal hoses that have part numbers assigned are heat formed so that they maintain the hose diameter when bent to a 90 degree corner.) 2. There was a 1986 OMC service bulletin 2159 that talked about the new fuels. At the time, new gas was first being produced with no lead at all. That became a concern for powerhead durability. The bulletin addressed the engine timing. If you ran with the normal 87/89 octane, that crossflow engine should have it's timing reduced by 4 degrees. If you chose to keep the timing at the high factory setting for performance, you could do so only if you ran 91 octane fuel. That's your call on how you want to handle that issue. Ethanol fuels are ok, if fresh. 3. If the fuel is 3 months old, it's probably ok. When I store over the winter (6 months,) I drain my tanks completely-then get fresh fuel in the Spring. If the fuel is over 6 months old, I would dispose of it-burn it in your car or other 4 stroke engine like a lawn tractor. The ethanol in the fuel attracts water over time and really old/stale fuels can go through a bad process called "phase separation"-when the ethanol separates from the fuel and settles to the bottom of the tank, along with the water. 4. A three year old Mercuy service bulletin states that their preference for long-term storage is to drain the fuel tanks completely-the opposite of earlier preferences to fill it for the winter. 5. Today's lead free fuels are harder on the crossflows-they tend to accumulate carbon around the ringsets more than when we had leaded fuels. Bombardier makes a product called Engine Tuner. You can give your engine an annual dose of this and it really works to keep carbon of the pistons/rings. If you think that decarb process takes too long, you can purchase their XD50 2 stroke oil-it has that carbon guard additive measured into it-which works as you operate the boat.
