5.5hp Evinrude pressure conversion issues.

[Mantas]

Alright folks......I'm almost ready for reassembly and I have a few issues I need feedback on. The manifold and carb nipples are for 1/8" hose, the Mikuni pump has 1/4" hose nipples, the fuel connector has a 3/8, AND the hole in the cowl plate that the hose has to run through is for at best a 3/16" hose. How do I make all these agree with each other without getting crazy with a bunch of double barb reducers and more and more clamps (for leak points)?

 

[Mantas]

Could I at least clean up the exterior by using a connector like this with a threaded portion and then using a barb to reduce it down to 1/8 hose so could go through one of the cowl holes? Does anyone know if these threaded connectors had NPT threads?

 

[Crosbyman]

what I have done in a similar situation is I simply added an extra inline filter
which had barbs for 2 sizes it allowed me to connect the fuel source on one side .......then the thinner barb was used to feed the carb . extra filtering won't hurt anyway

as to the pressure out nipple ...... to the mikuni the 1/8 hose can usually slip on the 1/4 nipple with a bit of oil or grease .... warm up the hose to soften it up on the 1/4 nipple

 

[racerone]

You can not use that nipple ( as is ) on the intake manifold to run that mikuni fuel pump.

 

[Mantas]

You can not use that nipple ( as is ) on the intake manifold to run that mikuni fuel pump.

Nice observation (the manifold screws are still factory painted over and have never been off)....I fibbed a little as I'm not exactly ready for reassembly, I still have to seal up one side under the manifold and take out the check valve system. Thanks for looking out.

 

[oldboat1]

Before getting in too deep on too many systems, I would try to put it back together in original shape and run with a purchased or borrowed compression tank. When you know you have a runner, mess around with conversions if you like -- or stick with the simple and dependable compression system. Rebuild a tank if needed. (Just my opinion with a lot of experience with the whole '57 line.)

 

[Mantas]

Before getting in too deep on too many systems, I would try to put it back together in original shape and run with a purchased or borrowed compression tank. When you know you have a runner, mess around with conversions if you like -- or stick with the simple and dependable compression system. Rebuild a tank if needed. (Just my opinion with a lot of experience with the whole '57 line.)

It ran perfect when it went into storage in 2004 and has all kinds of compression. Its my childhood motor so I'm getting it going regardless, if I had to replace the rings I'd replace the rings. The original tank must have took on some condensation and developed a small rust ring in the bottom 1/16 of the tank that turned into some pinholes. I bought a second tank that needed work too so I thought I might as well modernize it. If I have any problems with the pump system I can easily get it going with a gravity feed.

I just need to handle the different hose sizes with any sort of elegance. I'll try heating and lubing up some 1/8" fuel line and see if it attaches to the Mikuni (1/4) but that is a lot to ask for since the nipple is doubling the size requirement and not just off by a little.

 

[oldboat1]

Getting old(er), and meant to refer to pressure tank system, not engine compression. Admit to preferring the system, and imo would spring for a working tank in the $30 to $50 range (there is some profiteering out there). It sounds like you already have the two line connector, and having that little jewel in hand should cut costs.