Identify Evinrude Engine Part from Photo

[Oldslowandugly]

I am fixing up a 1996 Evinrude 48SPL. See Figure 1 below, and identify the hose and its purpose.

Fig. 1 Unknown hose fitted to crank case whose purpose is to be identified from this photo.

IMG_0799.JPG (220.05 KiB) Viewed 722 times

The hose seen in Figure 1 above attaches to a fitting that looks to me to be screwed into the engine crank case. The [other end of the] hose is plugged, so whatever its function was, it has been defeated. The usual drain hose from the bottom of the intake manifold to the air box is there where it belongs.

ASIDE
This engine came with a set of remote controls that used the System Check which consisted of gauges and sensors to alert you to problems. I don't know what kind sensor would read crank case pressure/vacuum, and for what purpose.

I also think the remote controls are not the ones that belong to this engine. It had trim-and-tilt on the throttle as well as all the System Check wiring. The SPL engines had no oil injection, tilt, or regulated charging. It is even possible this powerhead has been replaced with something different.

[Oldslowandugly]

I'm sorry it took a while to get back. I think I figured it out.

The fuel pump uses the alternating positive and negative pressure pulses in the crank case to operate the pump diaphragm. That is how it pumps the fuel. There are two models of fuel pumps.

One kind uses a port on the back side of the pump. That port connects to the pressure passage on the crank case. The mounting gasket has three holes. The two outer holes are for mounting bolts. The middle hole is the pressure port. This model pump has only two fuel fittings, in and out.

The other kind of pump has three fittings. In addition to the fuel in and out fittings, the third fitting is for the crank case pressure. A hose goes from that fitting to the fitting I showed on the crank case.

I had never seen that type of system before. Every fuel pump I have ever seen used the port on the rear of the pump for the crank case pulses. What is odd is that this power head has the fuel pump mounted normally with the pressure port behind it right on the crank case, and it also has the fitting located at the bottom. I now see both types of fuel pumps in catalogs. I have no idea if there is an advantage to either design. Perhaps, if the power head configuration left no room for normal mounting of the pump on the side, it could be mounted elsewhere, and the bottom fitting used to operate the pump. That would require the unused port to be blocked off, as I have done.

[goldstem]

Possibly this motor was converted from a VRO mixing-pump stock configuration to a premix-only no-mixing pump.

[jimh]

I think the model designation 48SPL—if that was the actual original model—might not have used the VRO mixing pump.

Compare at:

What Does SPL Mean on Certain Models of OMC Outboard?
https://continuouswave.com/ubb/Forum3/HTML/005043.html

[Oldslowandugly]

Jim: excellent thread about the SPL line. I was told by my OMC guy it meant Special. No oil injection, no Trim-N-Tilt, no regulated charging, but otherwise the exact same as a 50hp. My FSM even lists the carburetor jets as the same for the 48 and 50. These are rock solid simple motors.

This is supposed to be 1996 48SPL. But I have found quite a few discrepancies as far as parts. I am beginning to think this may be a Frankenstein motor built or repaired with parts from other motors. My 1993 48SPL uses the side mounted fuel pump, with the two fuel fittings, directly powered by the crank case port. My 1996 FSM says this one should be the same. But it has that extra crankcase fitting. Did the VRO equipped motors use the crank case fitting I showed?

The guy I bought this from in Baltimore, said the guy he bought it from was a 'tinkerer'. I have been undoing much of the 'tinkering'.

There are a couple of pressed in plugs that fill holes in the powerhead. They usually have the motor ID number stamped on them. Mine has some sort of number, but it looks like it was etched with a hand held etching tool. It starts with 48, but the rest are hard to read. A stock number would start with a J or an E.

I plugged the port where that fitting was screwed in. I will chalk it up as just another strange part on this motor.