evinrude fast twin 15

[Ezrider_92356]

i have an evinrude fast twin 15 im guessing early 60's model i want to use as a kicker, its got good compression numbers and appears to be in good shape, but it looks like it has the old 2 line fuel tank setup what is needed to convert it to a single line setup?

 

[jbjennings]

Re: evinrude fast twin 15

I believe you have a '56 or older fastwin....In '57 the fastwins became 18hp.
There are some neat threads, in the FAQ section I think, that will show you how to convert it. You'll probably need to drill a hole in one of the intake covers, then tap it for a brass nipple to get vacuum to your fuel pump. You can get a mikuni pulse vacuum pump which are nice pumps or even a plastic briggs and stratton pulse vacuum pump for a lawn mower. Then about 3 or 4 feet of fuel line and you're in business. I really like my '56 fastwin 15. Why not use the 2-line tank? You have to have a separate tank for your 24:1 fuel anyway, right?
Curious,
JBJ

 

[Ezrider_92356]

Re: evinrude fast twin 15

i got the motor at a garage sale and it did not come with a tank, not that im complaining for $15 i have a couple spare jhonson/evenrude tanks but there all single fuel line tanks.

 

[jbjennings]

Re: evinrude fast twin 15

Wow! 15 bucks!!??? What a steal!
If it were me, I'd get myself a good used tank on ebay for about 50 bucks. You'll have that in a fuel pump, nipple, tap, and fuel line/clamps in the end.
The coversion is handy, though, and faster to get the parts to fix it compared to waiting for a pressure tank.
Later,
JBJ

 

[Ezrider_92356]

Re: evinrude fast twin 15

i was just thinking i could probably drill and tap an fitting into one of my other tanks and hook that up to presurise the tank and then run another line from the one line conector on the tank and hook it into the 2 line connector on the motor, you you understand what im saying.

 

[tx1961whaler]

Re: evinrude fast twin 15

That probably wouldn't work. The tank with the fuel in it needs to be pressurized, so the fuel is forced to the engine. It sounds like you described having one (empty) tank pressurized, and another tank with fuel in it just sitting there not pressurized. Unless the two tanks are hooked together somehow, the pressure would have no way to force the fuel to the engine. It would be easier, if you're doing all of the plumbing anyway, to do the conversion to a fuel pump. Your current tanks are not designed to be pressure vessels in any case.

 

[Ezrider_92356]

Re: evinrude fast twin 15

no i was discribing having one take and drilling and taping a barbed fitting into the top of the tank for the pressure line.

 

[tmcalavy]

Re: evinrude fast twin 15

Don't know if that would work for sure. The old double-line tanks are built differently that our modern tanks. The conversion can be done for less than $50 to $70, depending on which pump you choose/use. I put a Mikuni snow mobile pump on my 57 Big Twin 35hp...cost less than $50 for the pump and new hose/fitting. I like being able to pick up any one-line tank in the shop and head for the water. The old double-line systems are reliable, too, and not dangerous as some claim.

 

[Sea18Horse]

Re: evinrude fast twin 15

I can see it being difficult to regulate the pressure properly. The pressure tanks have an automatic pressure relief valve that keeps the pressure inside the tank from getting too high. I wonder what kind of pressure a 15 horse at wot can produce?

I don't know how thick walled the regular OMC tanks are but the pressure tanks are pretty stout. Plus I don't know how well the caps will seal pressure. Obviously they seal a vacuum ok because running with a closed vent is a consistent problem.

My gut instinct tells me that converting or getting a proper pressure tank would be a better option. But I'm sure it could be done.

Cheers...................Todd

 

[jay_merrill]

Re: evinrude fast twin 15

You should not try to pressurize a single line tank! Either find the proper tank, in a safe and usable condition, or do the conversion - it really isn't that hard.

 

[Ezrider_92356]

Re: evinrude fast twin 15

i think i will just convert, i can probably use the fuel pump off an 1958 jhonson supersea horse 35hp that iv got laying around with a broken piston ring, that motor has a single line setup and the pump is good on it. ill take a look at it in the morning and see if i think it will work.