Evinrude zephyr

[frankr]

One crankcase chamber provides the pulses to move the fuel pump diaphragm, no matter how many cylinders.

EDIT: Actually, on opposed cylinders such as the Zephyr, two opposite cylinders share a common crankcase chamber. Same thing.

[Anonymous]

The rotary valve is likely gonna work to my advantage I think . It seems no matter how perfect I make the stock carb if the float gets stuck the carb will over flow . I don’t like that design . If I take the motor off and store it sideways in the trunk of a car or something I got a dangerous mess on my hands . The shut off isn’t going to work unless the engine is upright. The little carbs I have in mind don’t have any opening so upsidown rightside up they are not going to leak . Maby I don’t need to use the fuel pump feature as the tank is higher then the carb . I’m not clear on that . It may also be that no fuel will flow into the carb unless the diagram pump is actuated . I think the rotary valve on the crank shaft is probably why this zephyr carb works at all on the power stroke the valve is closed and no pressure makes it to the carb only vacuume makes it into the carb . So I have two schools of thought . Will a series of vacuume pulses actuate the fuel pump in the new style carburetor without any pressure to flex the diagram in the opposite direction. Or can I just have it gravity feed. Can the carb fuel lines be connected in sereas, as in fuel outlet to fuel inlet of the next carb as long as the last carb returns a little fuel to the tank then I know none of the carbs are starving for fuel ? I’m gonna give it a try post some pics if it get it working .

[Anonymous]

Just from looking at the thing I orinally thought that the top left piston would be moving outward while the top right moved inward and vice versa on the bottom but I had the spark plugs out out and that seems wrong . So right away I deduced that I’ll have vacuume on one intake hole and a pulse on the other . With a rotary valve on the crank perhaps it’s just constant vacuume. Another question how apps this ignition timing thing work? So far I can only get it running with the timing lever pushed to the side of the motor with the tiller handle is that advanced or retarted? And were should I run this lever when in use?

[frankr]

Maybe I’m wacko, but I believe the top right and top left both move outward at the same time and inward at the same time. Suction in the crankcase as they both move outward and pressure in the crankcase as they both move inward. On the other hand, I haven’t worked on a Zephyr in the last 60 years or so. And I didn’t like them when I did.

[garry-in-michigan]

You are right. They were advertised as having two decks of apposed cylinders firing alternately in pares. . . 😎

[gjonz]

No disrespect, and it’s an interesting concept, but it seems way overthought. Those carbs work fine. I even found primer pump washers for mine that worked with a minor mod. The big issue is making sure the spark plug wires have hoods on them to prevent sparking as mentioned elsewhere.

But yeah. Just seems like reinventing a mousetrap that needn’t be.

If you’re going to all that trouble, maybe pick up a dirt cheap OMC-built Sea King or Gale 5hp for 45 or 50 bucks and know it’s not gonna blow up and will always run.

However if this is an issue of a vintage craft with a cool motor, maybe it make sense.

Good luck. Hope to see how it turns out. I really am interested.

Greg

[Mumbles]

1940 Zephyr, I like them to! They aren’t really all that complicated once you understand how everything works and when everything is working as it should, they are great little runners!

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[garry-in-michigan]

I wrote this about a 1945 model . . . 😎

[billy-j]

Hello,I just read Garry’s description of a 1945 model Zephyr as having soft iron magnets in the flywheel. I have a 1948 Zephyr does it have alnico permanent magnets or soft iron magnets in the flywheel? Bill

[The Boat House]

Normally iron magnets are separate from the
flywheel and are held in with some type of fastener
while permanent magnets are cast into the flywheel
if the magnets are in the flywheel.

[Author]

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