1958 Johnson 18hp sea horse fuel connection

[Cbausch]

Hello all !, I bought a boat a bunch of years back and gave away the motor that came with the boat. Later in life the motor found its way back to me . Now I don't think the motor ran for about 15 years but I have faith in it so I brought it home put new plugs in it , gear oil and gas /oil mix , has the original pressurized fuel tank and 2 line connector on it. The fuel lines were dry rotted so I cut back to where it seemed ok to re connect to see if she even starts. Well everything is hooked up and I'm think so I have to pull this cord a million times till the fuel gets to the engine? So here ya go,

1. How do you prime the engine for fuel from the tank?
2. After I know it starts does anyone have a step by step to retro the motor to the single fuel line system ?

Thanks in advance on your responses

 

[RCO]

Pump the primer button on the tank until it's firm to fill the bowl on the carb (assuming the diaphragm is good in the tank). Single line conversion is very simple on the 18 hp. The easiest thing to do is get a transfer port cover from a 59 or later model, install OMC fuel pump, run new lines and block off the pressure port on the manifold.

 

[Cbausch]

I didn't see that there was a primer button on the tank I'll give it a shot and keep you posted , Any chance you would have part numbers? Youtube doesn't really have a video on the 18hp , they have a few on the 10 horse . I got my year mixed up I believe my motor is a 1960 Fd-14 if that matters now

 

[Chinewalker]

Ain't nothing wrong with the pressure tank. Simple, reliable and durable.

If your motor is a 1960, it'll already have a fuel pump and single line tank.

 

[Cbausch]

I'll look at the Fd tag on it when I get home to confirm the year , I know it has a double line on it so maybe I'm wrong ,

 

[Chinewalker]

If it has an all metal cowling, it'll have a dual line tank. Or at least it began life with one...

 

[oldboat1]

If you have a working pressure tank, I would get it up and running with that system (some bias on my part, as I like the system). You can find replacement dual hoses if you need to. Check the tank for varnished up old fuel, of course, and may need to clear the intake screen.

If the motor has a glass fuel bowl in place, will want to clean that and make sure the seal around the edge of the bowl is good. The filter inside the bowl can be replaced, or you can try running without the filter if trying to troubleshoot fuel issues.

Otherwise, it's the usual stuff. There should be a plate on top of the flywheel -- can be removed to view the coils (If cracked, replace them). You can also dress and set the points with the plate removed.

Check compression. Champion J4C plugs (J4J originally). Gap to .030. Fuel ratio is 24:1.

 

[Crosbyman]

you need to read this book of knowledge..

.http://boatinfo.no/lib/johnson/manuals/1922-1964johnson.html#/0



page 126 explains the mile master tank and... the pump button

 

[Crosbyman]

No Title

converting to a single line is easy and involves a few basic steps

1- remove 2 line hose from the motor
​2- The AIR side behind the carb needs to be pluggged. Use 1-2 inch piece of hose on the nipple and plug the end with a large enough short bolt and clamp
​3 You need a vacum pulse to drive the external pump. you can drill and tap a cover port to mount a nipple in and route vacum pulses to the new pump
4- hook up a new pump like a Briggs-Straton ($15$) or a Mikuni
​5- route a fuel fuel line so the single line fuel conector replacing the old 2 line one and a fuel line to the carb inlet nipple

​pump types can vary as pictures ..some side cover plate styles from more recent motors should fit your FD and allow direct pump mounting .. The square Mikuni is on a FD 15hp .

do a search on this site....some of these photos are not mine..(square OMC and the round B&S)

Keep all spare parts like the 2 line side connector in case you want to retrofit later .

 

[Cbausch]

Thank you guy for your help , as soon as I get home I'll start working on her , I'll keep everyone updated , west marine is down the street from me .

 

[Cbausch]

Ok I have a Fd-13r, what's the R mean ? , I think I'm going to go with the external pump method . You I still have to tap and die if I use a external pump ?does anyone know the park number for the new pump?

 

[F_R]

The R identifies any mid-year changes IF there were any changes. Otherwise, it means nothing.

As crosbyman indicated, there are several pumps to choose from.

 

[Crosbyman]

the OMC is expensive (+_ $80) but a neat installation driven directly by the pulse hole drilled or available behind it in the cover plate... it is easier to mount if you find the newer molded side covers prepared for mounting the pump

​ the Mikuni/B&S I used is #808656 sold as a B/S product but.....marked as a Mikuni Japan made. they are very common on small lawn tractors bikes etc... they are sold with different names (Khoeler etc...)

​easy to find & dirt cheap in the US ... about $25 CDN

The square Mikuni works to but I do not have the mdl number

easy to google it up.

​if you go square mikuni on the starter recoil frame or order type make certain the pump does not interfere with linkages or cowl closure

 

[Cbausch]

Ok now for the side plate that I have to drill out and tap , it's a 5/16ths drill bit and fitting ? With a 1/4" barb end in guessing right? Also what size fuel lines are you guys using ?

 

[oldboat1]

compression on my '57 18 is 130 top and bottom -- just saying you might first want to see what you have.

 

[Crosbyman]

3/16 -1/4 hoses is about right but check the pump nipple sizes and side connector.

has for the cover it is a NPT or NTP something nipple in the automotive stuff .... get the exact size and drill about 1/8 less for tapping out the threads....

do a look-up on tap and drill sets for exact drill size .

 

[Cbausch]

Alright I'm a little confused for some reason , if I go with the tap and dye method with the fitting I would still need a fuel pump right? What's the easiest method to do the conversion on the 1959? I can't find a walk through for the barb method for my exact motor .

 

[Chinewalker]

Easiest method - use your pressure tank as is.

Second easiest, find the intake port cover from a 1960 or newer 18/20 hp, plug the pressure feed nub, install a fuel pump and go.

 

[Cbausch]

Thanks , alls I need to know is what size Barb fitting do I need to use ? And use line size to reduce all the lines i have a pump already

 

[Crosbyman]

No Title

just get a 90 degree nipple about 1/4..... with thread diameter size to match the cover plate molding

drill out the hole small enough to leave enough metal to form the threads for the elbow


​ that becomes your vacum pulse for the pump the rest is IN and OUt fuel ports to hook up ... nothing elaborate

sorry my stuff is all at the cottage