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1984 Eska 7.5: runs at 1/2 choke only

Cashdds

New member
Gentlemen,
I have the aforementioned engine, #640-19D, Eska model 14209-B.
I have:
1. Used brand new gasoline in a 50:1 mix ratio with marine 2 cycle oil.
2. Disassembled the carburetor and soaked, scrubbed, resoaked and scrubbed every square millimeter of it.
3. Run ultrafine wires through all holes, even up through the internals.
4. Replaced all gaskets and needle seat, red rubber fuel pump, membrane fuel valve and gasket.
5. New bowl ring
6. Replaced BOTH gaskets attaching the carb to the main body of the engine.
7. Quadruple checked all screws for tigntness.
8. Replaced the points, checked the timing
9. Measured the points gap to .020.
10. Installed a new spark plug and set it at .030.
11. Installed new fuel lines.
12. Removed the side engine plates and visualized the piston with transillumination to confirm no corrosion/pitting.
13. Replaced both side plate gaskets when reassembling.
14. Visualized that both fuel inlet ports are not clogged.

Had the engine running then on one trip she would sputter out after about 10 min at full throttle. After several pulls, she would go 10 minutes more. Then the very next day, she wouldn't turn over and run except at 1/2 choke.... and only for 1-2 minutes then "bucked" several times and stopped
SO... I disassembled the carburetor, cleaned it AGAIN as above, checked all valves, holes and gaskets for patency as well as the fuel screen.
Rechecked all my fuel lines...
Now, in my driveway, in water, she will fire up and run ONLY at 1/2 choke without cutting out. I have adjusted the air/fuel mixture through the full screw capabilities to no avail. Any choke position in or out from 1/2 causes mild buckling and shutdown.
Most 1/2 choke problems I have read about here seem to be gummed carburetor issues, but everything is new and clean enough to eat off of....
(Yes, the fuel tank is open and vented)

Apart from putting a bullet in this engine now or punching the engineer who designed the layout to be the most "pain in the ass" for carburetor access, can anyone guide me as to what I am overlooking or what happened?
Sincerely,
Cash
 
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I also checked for good compression and it is o.k., within specs... as now she will run consistently at half choke in a bucket..with no fuel leaks.
 
O.k., update....
Took her apart again...
1. checked points, gap good, BUT... I found a bend in one of the wires coming off the capacitor that ever so slightly contacted the metal... i mean you could barely tell she was contacting. So I bent her back off the contact point and got BIG TIME spark... I assume she would run and vibration and heat would eventually create enough expansion and or movement that caused the engine to ground out.... hence the knocking and eventual cut off.

put her back together and she fired right up. ... ran her for 10 min... shut her down but then she wouldn't start again...
Going to let her cool and try again tonight... crazy motor!!!
 
Solved the issue...

As this is quite old, the carburetor rebuild kits are obviously aftermarket. So.....
I examined the small 2 valve membrane that serves as the "fuel pump" right where the fuel line enters the Carb.
What I noticed was that on ALL 4 of the replacement membranes I ordered, there was an incomplete stamp cut of the membrane. This left a very small piece of material in a position that did not allow the membrane "flap" to move up and down.
I removed this with an exacto knife and now it starts on 1 pull. And, once warm, no need for 1/2 choke anymore!!

Lesson learned... always inspect your aftermarket membranes and gaskets carefully...
 
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