'86 Mercury 35HP 2-stroke compression

[LaqueRatt]

Fuel tank suggestion: Buy another old metal one. Clean them up real well, throw a coat of paint on them. Buy new hoses. The new plastic tanks seems to me to be pretty crappy. I'm using older plastic and metal tanks that have vents in them. New ones no longer have vents. They reportedly blow up like balloons when they get warm. No thanks.

 

[Pappy]

Just a question....why are you replacing the metal tank? Those are great tanks and are becoming sought after? Unless it is rusted out on the bottom either inside or out I would run it.

 

[markscottsboro]

Need tach readings to make prop adjustments, otherwise your just guessing !! As far as fas tanks, how much fuel do you go thru on an outing and how often do you want to get gas. Based on my personal usage, I would go with 1 six gallon and one 3 gallon, but if you run longer you may want 2 six gallon tanks. When I was running small tanks ( now have a builtin 17 gallon tank) I would keep a couple 2 1/2 gallon cans mixed with oil on the ready. Easy to add and properly mixed with correct oil ratio. When you keep adding to a premix tank and guessing at oil ratio, things can get off abd mix ends up to rich or to weak...by premixing in known volume containers your oil ratio will be better controled. Use good quality plastic containers with vents, stay away from Chineisum quality with all the epa crap. When I had a small outboard, I would have a six gallon tank and carry a couple 2.5 gallon cans of premix to add if needed. Only you know how much fuel you need for an outing, just make sure you have extra to get you back if conditions get rough.

Unfortunately, this vintage boat doesn't have any instrumentation... so I've started looking at adding a tach and a GPS speedo (I know phones can do it, but would rather not depend on phone). I really wish there was a way to add temp gauge (if that's meaningful for outboard?)

 

[markscottsboro]

Just a question....why are you replacing the metal tank? Those are great tanks and are becoming sought after? Unless it is rusted out on the bottom either inside or out I would run it.

Boat mechanic suggested getting rid of metal one due to potential rust/contamination in the fuel... we cleaned it out really well, but I personally didn't see how the inside looks. Outside is in fantastic condition, very little rust. Will probably keep running it for now.

 

[lckstckn2smknbrls]

Unfortunately, this vintage boat doesn't have any instrumentation... so I've started looking at adding a tach and a GPS speedo (I know phones can do it, but would rather not depend on phone). I really wish there was a way to add temp gauge (if that's meaningful for outboard?)

Look at "Tiny Tach's" or any of the similar tachometers.

 

[LaqueRatt]

I'd be leery of this "mechanics" advice if he told you a metal tank is a problem.

As for instruments, my new boat has speedo that apparently works off of pressure. A little piece goes on the transom and then you just run a small hose to the speedo that has a nipple on it.....I think. All I've had to do so far is change the part on the transom. I'm also wanting to install a tach. Already have a tiny tach and was going to install it permanently, but after a little more thought think I want something that matches the speedo which is round with a chrome ring. Not sure about a temp gauge. As long as the motor is peeing I think maybe you don't have to worry about motor temp?

 

[airshot]

Boat mechanic suggested getting rid of metal one due to potential rust/contamination in the fuel... we cleaned it out really well, but I personally didn't see how the inside looks. Outside is in fantastic condition, very little rust. Will probably keep running it for now.

Look inside that metal tank...look carefully and see if there is any corrosion. If fuel/oil mix is keft in them they normally don't rust or corrode. If no signs of corrosion then by all means use it !! If there is any corrosion then switch to a good quality plastic tank, but make sure there is a vent. If the metal tank has some not to serious corrosion and you want to keep things original, there are coatings for the inside of metal tanks to seal them up and stop corrosion. They work well if done properly. I recomended a plastic tank in an earlier post, but was under the assumption your metal one was corroded.

 

[Billy H]

If the metal tank has some not too serious corrosion and you want to keep things original, there are coatings for the inside of metal tanks to seal them up and stop corrosion. They work well if done properly.

I’ll add that you can take the tank to a radiator shop and have it “cooked” out. I’ve put many old motorcycle tanks from the 1930’s and 40’s back into service after a good clean and using liner products. POR-15 is one and Dragons blood is another. Many products out there. Google up motorcycle gas tank sealer. As air shot said it has to be done properly.

 

[LaqueRatt]

I'm no expert, but have done a bit of old motorcycle restoring. If your tank has flaky stuff in it a shot of kerosene, a handful of BBs. and some vigorous shaking will often be all you need to do. The coatings are great, but I don't think rust will ever be an issue as long as you don't let it sit around empty. Just my thoughts, if I got it wrong feel free to edjimicate me.

 

[airshot]

I'm no expert, but have done a bit of old motorcycle restoring. If your tank has flaky stuff in it a shot of kerosene, a handful of BBs. and some vigorous shaking will often be all you need to do. The coatings are great, but I don't think rust will ever be an issue as long as you don't let it sit around empty. Just my thoughts, if I got it wrong feel free to edjimicate me.

Years back an old friend had a motorcycle tank with a bit of rust inside. Added trans fluid and kerosene and small gravel, let it sit on a shaker for a number of hours. Once cleaned out, looked almost new inside. The sharp edges on the gravel pieces removed every sign of rust and corrosion.

 

[Pappy]

Fish tank aggregate is fantastic for that. Just have to make sure it is the 'real" stuff....ask me how I know.