Home › Forum › Ask A Member › 4 gal Evinrude tank, pressure or suction?
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oakhurst.
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March 22, 2017 at 6:09 pm #6589
Trying to start my 1955 Fleetwin which appears to be in excellent condition. Trying to check the 4 gal tank, two hoses, one fuel and one air. Not sure if it is working. Does the "pump" pressurize the tank to force fuel to the engine, or does it suck fuel through the strainer into the fuel side of the hose?
Is the "air" side a fuel return? I don’t understand how it works, so I don’t know how to check it.March 22, 2017 at 6:27 pm #54712the air line pressurizes the tank whicht then forces the gas into the engine carb
to start the pressurization of the tank……. you MUST prime the carb by pumping the gas up to the carb bowl with the push button ( about 10 times) on top of the tank otherwise the carb will be empty of fuel and the engine will never start to… pressurize the thank
make certain the tank screw cap is tight otherwise you will loose that precious air pressure needed to push the gas up the fuel line.
before you start your oldie you should check your impeller..and gearcase oil
https://www.youtube.com/watch?v=GCkpGD4bgDIcheck your plugs (out & grounded) to see if at least you have sparking when pulling the starter rope
if it is a real oldy the coils are cracked for sure (if never replaced) you will need to service the ignition suystem … visit Leroy’s site and utube for lots of good info and videos. with all the info available here on this site and lots of coaching you can do it !!
http://www.leeroysramblings.com/johnson_magneto.htm
changing the impeller is not hard but the fleetwin needs to have the head pulled off…to release the L.U. gearcase. that usually means getting a gasket for the base of the powerhead when reassembling .. most parts are available but figure on about 100-125 $ in parts for another 50 years of service….if the rest of the engine is OK
try to get a compression meter to measure each cylinder for at least 70-75 pounds… most like 80-90 and up but mine has worked flawlessly with 70-75 pounds
http://www.youtube.com/watch?v=SVOedhzPP7M
https://www.youtube.com/watch?v=3afgQKYByFoyou are at the starting point …. of a fun journey and a great hobby fixing these oldies
here is a book to read up on it’s maintenance you will find pretty well everything you need Johnson and Evinrude are twinns
http://boatinfo.no/lib/johnson/manuals/ … on.html#/0
Joining AOMCI has priviledges 🙂
March 22, 2017 at 7:02 pm #54713Thanks for the info. If I pump the button with the hoses not connected to the engine to check it out, should I see fuel out the end of the hose when i push in on the end?
March 22, 2017 at 7:05 pm #54714If I understand it correctly, it will be easier to prime the carb if the tank is near full as the liquid will not compress. The less air in the tank, the faster it will prime, correct?
March 22, 2017 at 7:12 pm #54716the push pump is a pump…not a tank pressurizer it will pump gas…. up to the engine by check valving the gas…. one way up the fuel line… nothing to do with the quantity of fuel in the tank
the hose female end will not let fuel out unless connected because of the internal spring valve
looking at the glass bowl and pumping the button you will see fuel entering the glass bowl up to the carb …. the bowl has a metallic filter which… may be dirty and require cleaning to allow fuel into the carb.
since you seem to be at a lower knowledge level on this stuff maybe a good read of the johnson book will answer all your question (no offense)
one great beginners book is CHEAP OUTBOARDS by Max E Wawrzniak ISBN# 978-1-891369-62-9 http://www.breakawaybooks.com
https://www.kobo.com/ca/en/ebook/cheap-outboardsJoining AOMCI has priviledges 🙂
March 22, 2017 at 7:24 pm #54717Your first comment says "the air line pressurizes the tank." That is what confused me. I will go and try again. The motor did "kick" with a little WD40 sprayed into the hose connection on the engine, so I think coils are OK. Be back later. Thanks again.
March 22, 2017 at 7:37 pm #54718If you look under the fuel connector you’ll see each side marked air and fuel. The air line is receiving air from the operation of the motor. The air outlet is a nipple on the manifold and a short hose going to the motor side connector. When you plug in the connector, that air now travels through the air line into the tank and pressurizes it enough to force fuel back up through the fuel side, through the connector, hose, and into the carb/filter bowl.
March 22, 2017 at 7:39 pm #54719The engine must run to pressurize the tank. The fuel tank cap must be tight.
The pump on the tank is only for filling the carburetor to start the motor.
Once running it is a closed loop system. Fuel is pushed from the tank by air coming from the motor.
This is simplified but should help
March 22, 2017 at 8:01 pm #54721Thanks guys, I get it now. Will hand cranking the motor over trying to start it send air down the hose to pressurize the tank also?
March 22, 2017 at 8:16 pm #54722Probably not enough to make a difference, but that’s not needed at first to start the motor anyway. Your first concern is getting fuel to the carb. Once the motor starts the pressurizing will take place automatically, assuming there are no other leaks anywhere such as the cap, tank gasket, or at the connections or the return line itself.
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