Aviation fuel in the dingy outboard

Here in CA we have a problem with pump gas because of the high ethanol content. I've been told that since Av gas has no ethanol, I should use it in my outboard. Now I read that my yamaha outboard will have fouled plugs and build up on my valves if I use the leaded Av gas....

Anyone out there have any experience using Av gas in an outboard?

Check around the marines for unleaded gas, no ethanol. Last time I bought some for my outboard, it was $4/gal.

Aviation gas these days are 100 LL for Low Lead, not sure if that is enough to foul up the engine?
Some marinas sell no-corn fuel, tried to use it on my outboards, but expensive.
For 100 gallons and more a truck comes to my dock with pure fuel at $3.05 per gallon, but don’t use this quantitative anymore. (Had a Glacier Bay 2770 last year with 2 thirsty 150 HP Yamaha’s)

Use to use Mogas (an aviation fuel) in my ultralight. It's unleaded, but no ethanol. Don't know if it's available in CA.

Ted

Our little airport only has one pump, it's low lead 100oc...I know I can by true fuel at the auto supply store, but they want 7.99 a quart! That works out to $32 bucks a gallon...

Here is a search directory for Mogas. Apparently not very popular in CA.

Auto Fuel Locations | Mogas Locations

Ted

O C Diver said:

Here is a search directory for Mogas. Apparently not very popular in CA.

Auto Fuel Locations | Mogas Locations

Ted

Click to expand...

Call before you go. Seems the list has not been updated in a while.

We tried 100LL in ultralight aircraft.
Never seen so much grey-black soot on spark plugs.
It’s like low salt food in the store. Just reduce the salt amount 3% and it’s “low salt”.
There’s so much lead in avgas 100LL that you’ll probably fowl the plugs on 4 stroke OB’s and of course 2 strokes are even worse.

Use 2-stroke oil and auto gas.

Ted, how long or much did you use 100 LL?

I say try it. You won’t hurt it. Airplane engines are very simple, most are carbed. You don’t want to use it in a car with modern emissions. But an older car with none of that will be fine. I don’t see how your outboard is any different and why it would foul the plugs.

OldDan1943 said:

Call before you go. Seems the list has not been updated in a while.

Click to expand...

The only one listed in CA is down in San Carlos, that's a 6hr drive one way for me...At that rate, the $35 a gallon stuff from the auto store is cheaper..LOL

Guess I'll just use Valve Tec gas and hope for the best..

100ll has .5gm lead per liter, higher than racing gasoline. It is low lead only in comparison to 130/145 octane aviation fuel which was developed for WW2 fighters and is not sold anymore. I would be very reluctant to use 100ll in any motor with an O2 sensor.

There are many thousands of Yamaha outboards in California, let alone the US of A. Why don't you consult:
1) Other owners
2) Yamaha mechanics/dealers
3) Yamaha themselves

Never had a prob running my Yamaha 9.9HT on regular gasoline from auto pumps. Owned that motor 18 years and it was used when I got it.

"Here in CA we have a problem with pump gas because of the high ethanol content"

The problem may be that ethanol grabs water from the air and leaves it in your fuel.

Simply use fresh fuel, so there is little time for the bio gunk to add water to your fuel.

A 3 gal metal OB tank might work best. Use the gas in your car , don't save it.

If you need to carry fuel for a long cruise use the old army style gas cans , which are not vented.

If you need to mix oil with your fuel (2 stroke?) add the oil just before using the fuel, and be sure to use oil for water cooled , not air cooled 2 strokes like a chain saw.