Double to Single Fuel Line Conversion

[jay_merrill]

Re: Double to Single Fuel Line Conversion

One thing that I will add just because it always seems to be forgotten - when you do the conversion, you must close the pressure souce for the old tank. It is a nipple which is located on the bottom front of the intake manifold cover. The most simple way to do this is to remove the nipple and replace it with a screw of the proper size, thread count and length. A crush washer can be used under the head of the screw to seal it. ALso be sure that the screw is not too long, because it will hit the leaf plate located inside of the manifold if it is.

Your motor will still run if you forget to do this. but each pressure pulse will spray pre-mix all over the inside of your cowl and make a mess.

 

[58CorrySuburban]

Re: Double to Single Fuel Line Conversion

Ok,

So to recap, I need a 380016 (or its modern equivalent), screws and a crush washer.

By nipple you mean the male end of the fuel/air line?

Do I just unscrew the nipple, bring it to the hardware store and match it up?

Josh

 

[asdasc]

Re: Double to Single Fuel Line Conversion

On the iBoats parts store, they don't list a Sierra replacement for the 380016. Any ideas which Sierra part it is?

 

[jay_merrill]

Re: Double to Single Fuel Line Conversion

The new OMC/BRP number is apparently 388685 - try cross referencing that.

 

[jay_merrill]

Re: Double to Single Fuel Line Conversion

Ok,

So to recap, I need a 380016 (or its modern equivalent), screws and a crush washer.

By nipple you mean the male end of the fuel/air line?

Do I just unscrew the nipple, bring it to the hardware store and match it up?

Josh

Just follow the pressure line to the area under the carb, on the bottom face of the intake manifold cover. You will see the nipple, onto which the pressure line is attached. The base of it should take about a 3/8ths wrench for removal. Yes, you can go to the hardware or bigbox HI store to find a screw as a replacement. I would use stainless steel only. Once you find the correct size and thread count, select a length that is about the same as the threaded portion of the nipple.

 

[jay_merrill]

Re: Double to Single Fuel Line Conversion

Not to belabor the point about fuel pumps, but I was looking for something in my shop today and found an old fuel pump. It is just like the one in F_R's photo, but the fuel line nipples are on the bottom, rather than the side. I don't know what the prt number would be for it.

I held it up against the pumps on my Bigtwins (see above photos) and it is definately a bit shorter. I think F_R is right in that the pump he was referencing, as well as the one I just mentioned, would fit this application mounted right side up. What I don't know is if rebuild kits are still available for them.

 

[samo_ott]

Re: Double to Single Fuel Line Conversion

Sounds like you just just need to turn the pump sideways and it's the same one!!!

 

[58CorrySuburban]

Re: Double to Single Fuel Line Conversion

I edited this post. At first I couldn't find the part on BRP.

 

[58CorrySuburban]

Re: Double to Single Fuel Line Conversion

I just searched "OMC Parts" in google, found a site and searched the "388683" number and it pulled up a fuel pump for about $70, but it listed 592520 as the old part number. Should I be concerned that the old part number isn't listed as 380016?

I know this is kind of dragging on, but I just don't want to order the wrong part.

Thanks again for everyones' input,
Josh

 

[F_R]

Re: Double to Single Fuel Line Conversion

go to www.ishopmarine.com/ and type 380016 in the search box.

You had a better offer that I guess you don't want.

 

[58CorrySuburban]

Re: Double to Single Fuel Line Conversion

FR,

I'm sorry I don't know what you mean by: "You had a better offer that I guess you don't want"?

Maybe I missed something within earlier posts, but if there is a better offer I want it!

 

[F_R]

Re: Double to Single Fuel Line Conversion

I sent you a PM (Private Message) on Oct 22. I'll resend it just in case it got lost somehow.
Maybe you don't know about PMs? Go to the top of the forum page where it says "Welcome (your name)" and click on the private message link. It also should appear in your e-mail.

 

[jay_merrill]

Re: Double to Single Fuel Line Conversion

Don't worry about the thread dragging on. OMC made many motors over many years, so its hard to keep track of individual motors, never mind all the parts that were made for them.

Some of us even like it when the topics get into small details because we learn alot. To me, its kind of like reading a service manual over and over, because you learn something new, or develop a better understanding of it, each time you do.

The bottom line, though, is that we end up helping the OP do what he or she needs to do.

 

[58CorrySuburban]

Re: Double to Single Fuel Line Conversion

Thanks for the link FR, I saved it to my favoriates for future reference.

When I'm done with the conversion I'll repost on this thread, so anyone searching in the future will have the whole thing begining-end.

Thanks again,
Josh

 

[58CorrySuburban]

Re: Double to Single Fuel Line Conversion

I found a used fuel pump at a swap meet for free. I don't know what it came off of. I made the conversion today and it worked! I was able to mount it to the bottom plate, and retain the old fuel filter location. I was also able to mount it up-right (the pump actualy had "UP" writen on it) without any interference. I'd put a picture of the finished project on, but I don't have a digital camera. I'll borrow one and get a pic.

Thanks again for eveyones help, it definately prevented me from making some major mistakes.

Sincerely,
Josh

 

[1946Zephyr]

Re: Double to Single Fuel Line Conversion

Yea, to reiterate on how important it is to close off the nipple on the bottom of the intake minifold. That nipple spays fuel mix out along with the air pressur to the twin line tank. And when that fuel air mix is blowing out the bottom and all over inside your engine cover and you have spark jumping around up inside your flywheel, then things could get pretty ugly.

BOOM!!​

This is one of the other reasons, why twin line tanks were discontinued.

If I'm not mistaken, the twin line tanks fist came out on the 1949 Fastwin and 1949 Johnson QD 10hp. In 1951 Johnson and Evinrude 25 hps came out with it. It was also introduced in 1954, for the Fleetwins 7.5hp and Johnson CD11 5.5hp's It seems like the last motors were the 1958's. My 1959 35hp had a fuel pump which by the way was the rebuildable type.

I like F_R's pic of the outside mounting plate. Using that method, would allow me to buy a pump that is current, on the parts shelves.

Leon

 

[asdasc]

Re: Double to Single Fuel Line Conversion

I have an 18HP Rude and an 18HP johnnie, and both are 1959 models with the 2 line tank, so I think they changed in 1960, which may also be the first year with the thermostat.

 

[58CorrySuburban]

Re: Double to Single Fuel Line Conversion

Conclusion:

I got the motor firing on both cylinders and it ran strong @ WOT with plenty of fuel supply. Me being new to motors, I thought this project might be over my head. But after these posts and finding the parts, the actual work only took an hour or so!

Unfortunately, not knowing the part number or it's origin, this thread ends without a definative answer. That is, unless someone can identify the fuel pump. It mounted perfectly (up-right) on the lower cover, allowed me to retain my fuel filter in it's stock location, and provided my 35 hp Bigtwin with all the juice she needed.

Here are some pics of the projects outcome.

Thanks again,
Josh

 

[F_R]

Re: Double to Single Fuel Line Conversion

That is the "original" OMC fuel pump, first used in 1955 on the Gale 22hp and later all the Gale remote tank models. Johnson and Evinrude got it as a "Cruiser" accessory kit for boats with built-in tanks. Starting in 1960, Johnson and Evinrude put it on their under-35hp motors . There were a couple of part numbers for it.

They were good pumps, but very complicated and difficult to repair so OMC quit selling parts for it many moons ago. They said it was cheaper to just replace the pump than to fix it. And they were right because back then the whole pump sold for about $5.

 

[58CorrySuburban]

Re: Double to Single Fuel Line Conversion

Thanks F_R,

So, if this pump breaks there is no rebuild kits for it?

Is this the same as the "380016" pump we discussed, or is my current pump nolonge offered?