1993 50HP Evinrude Outboard - What size primer bulb?

[EricJRW]

I was replacing fuel line this past weekend and noticed my primer bulb has a small leak (when up to pressure and squeezed). I figure (since I'll be replacing more fuel line this weekend) that I better replace the bulb as well. My dilemma is that the fuel line on the engine side of the bulb is 5/16", but between the tank and bulb it's 3/8". This line is also grayish in color (and as I recall the word "Silver" was in the name). The OMC fuel line I am replacing is black, so I am suspicious of the gray-colored fuel line.

The 5/16" line fit the fuel pump and the bulb nicely so I'm pretty sure that's the right size. I'm thinking someone just "made due" with the 3/8" line and clamped it down a little tighter... However I do wish I had checked the size of the fitting on the fuel tank.

At this point I'm thinking 5/16" is the right size bulb and I need to hope new 5/16" line between the bulb and tank will fit the connection on the tank. Worst case it seems better to get the smaller line onto the bigger fitting than to have the line to big and have to rely on the hose clamp. Does that make sense?

BTW, the boat is 60 miles away, so I have to buy in advance, hence I'm trying to make "educated" choices.

Thanks,

Eric

 

[Joe Reeves]

Re: 1993 50HP Evinrude Outboard - What size primer bulb?

Unfortunately someone has replaced one of the valves in your original primer bulb.... they do not come equipped with two different size valves.

You have a choice to either purchase two different type primer bulbs and switch valves (not a good idea)... or to replace one of the fuel lines.

Personally I would change the fuel line(s) to have the fuel system original.

 

[EricJRW]

Re: 1993 50HP Evinrude Outboard - What size primer bulb?

Thank you Joe, I like that advice.

From a purest sense, does it matter if I buy fuel line from the auto shop or the boat shop?

In trying to solve another problem, I already replaced the line between the bulb and the motor (including a few bits after the fuel pump) with 5/16" line I bought at the auto shop. I now need to replace the smaller fuel lines that go to the carburetors. Since I'm off to the boat store to buy the smaller line, and since I'm going to be under the cover again, I could swap out the "automotive" 5/16" hose with whatever the marine shop sells, but I really don't want to if the fuel lines are functionally the same.

Thanks.

 

[69starcraft]

Re: 1993 50HP Evinrude Outboard - What size primer bulb?

I use automotive fuel line....i'm sure others will chime in, but I don't think it matters as much in small trailer lake boats. I use it in my motor.

Now if I was 30 miles offshore and depended on it with my life I might spring for marine grade lol

 

[Joe Reeves]

Re: 1993 50HP Evinrude Outboard - What size primer bulb?

The automotive fuel line hose will be fine. Cheaper and just as good.

Use caution on what you replace as some carburetor hoses are a different size (maybe not yours) and are formed (permanent curves).

 

[EricJRW]

Re: 1993 50HP Evinrude Outboard - What size primer bulb?

Fun day. I've now learned that my boat most likely had a VRO and it was gutted and replaced with a fuel pump. Since the fuel pump is the three-line type, i.e. not crankcase mounted as shown in parts diagrams, the hoses are also not the standard hoses with permanent curves. Thus I must use the "by the foot" option, as I'm pretty sure that's what was used to to this very non-factory job. In fact even the "zip ties" I removed are not the standard OMC type with the curve on the "head" (for lack of a better description). I won't even go into how the pump is mounted on the air silencer.

The other interesting thing is that with a VRO the fuel manifold has three lines going somewhere. When the parts diagram shows a fuel pump, one of the three ports on the fuel manifold is plugged. In both cases there is one line to each carburetor. However, on my motor, all three ports have hoses. Two go to the carbs, but I have no idea where the third line is going... Maybe it's plugged at the other end, which is hidden at the moment. Or maybe it still goes to the the primer, which is the case with a VRO. It's going to be a fun weekend.

In regards to the primer bulb, I'm going to see if 5/16" line will work to replace the 3/8" line. If that works I know a 5/16" bulb will do it. This bulb was nearly $30 locally, so the leak is not bad enough for me to mess with until I have the motor working. Then I will worry about the bulb (and buy it on-line). As an aside I see a 3-in-1 bulb for sale (at iBoats) that has adapters to make it one of three sizes. This gives me the idea that if the fuel tank fitting really is 3/8", I can by the 3-in-1 and mix and match the connectors.

Boy boats are fun.

Thanks for the advice.

Eric

 

[Joe Reeves]

Re: 1993 50HP Evinrude Outboard - What size primer bulb?

Pertaining to the three (3) hoses leading from the fuel manifold.......

Two (2) of course lead to the carburetors.

The remaining hose leads to the "Fuel Primer Solenoid" (replaces the older style electric choke butterfly). The fuel primer solenoid is activated when you push the key in.

 

[EricJRW]

Re: 1993 50HP Evinrude Outboard - What size primer bulb?

Thanks Joe.

So the mystery only deepens. When I look at the parts diagram, the Fuel Primer Solenoid only seems to be used with the VRO. Since I know my VRO was removed, I guess whomever put the fuel pump in just left all the other bits the same. So not that it matters, but I'm curious, why would a non-VRO apparently not need the Fuel Primer Solenoid?

Bottom line is that I now have 2 more lines to replace (Fuel Primer Solenoid to each carb). I'm debating the air silencer "drain" hose (that goes to the intake manifold. At the moment the line is disconnected, so I'm hopping the nipple is there. In all the gutting I'm sure it was pulled loose. I can see that the end of the hose once had a clamp... I just had no idea where it went. Since it does not carry fuel, I don't think it's that big of a deal, but since I'm going to have access to it, I figure I may as well replace it (if I can get it).

Thanks again!

 

[Joe Reeves]

Re: 1993 50HP Evinrude Outboard - What size primer bulb?

The fuel primer solenoid has nothing to do with the VRO setup. In essence, the fuel primer solenoid replaces the older electric choke setup. Without it, you'll have one hellava job cold starting that engine.

Without actually being there, I have no idea what you have or what you're missing, sooooooo if you don't fully understand the workings of that engine, it would be a good idea to contact someone who does in order to avoid expensive mistakes.

 

[EricJRW]

Re: 1993 50HP Evinrude Outboard - What size primer bulb?

Definately good advice. I have a shop manual (Clymer). I was also scrutizing the parts diagrams at shop.evinrude.com, and it's there that the fuel manifold from the fuel pump (vs. the VRO) has one port plugged (there is even a part number for the plug). It struck me as odd for the reasons you stated. At this point all I am doing is replacing hoses affected by ethanol. I suspect there will be more to do, but until I do this relatively inexpensive step I am reluctant to spend any more money than I have too.

I guess the real question is, "How does fuel get to the primer solenoid if not from the fuel manifold (non-VRO)?" That's what I can't figure out via the parts diagram.

Thank you for the help and the advice.

Eric

PS. In looking at my fuel pump, I see a housing screw (at the top) was removed in order to attach the pump to the air silencer. I'd like to replace that, and use the proper mounting holes (at the bottom). Unless someone here happens to know the size, I'll make another post for the inquiry.