Logo
FULL SITE MENU

uses all gas in bowl

B

Burchillb

New member
I have a 1979 15HP manual start Yamaha. When you start it, it will consume all the gas in the filter bowl and then shut off.
I prime (pump bulb) it until the bowl fills , start it and it does the same thing. What could be my problem? Is it a fuel pump or am I letting air get in somewhere. I looked at the diaphrams and they look and feel fine. I have no idea if you can look at them and tell If they are good or bad. Any help will be appreciated.
 
racerone said:
Possibly borrow / try another tank and hose.
Click to expand...

I've tried 3 different tanks, but I've only got 1 fuel line and bulb. Same things happens every time.
Just to give you some follow up info. I bough a new tank and line but never could get the primer bulb to get tight unless I turned and twisted the gas tank around. Got another tank and bulb tightens right up (when the bowl is full)
 
kimcrwbr1 said:
Does it have a three port type fuel pump? Possible pulse issue to the pump. Is the diaphram in the pump stiff if so put in a kit.
Click to expand...

I'm not sure what you mean by a three port. I looked at the diaphram and they were not stiff.
Can the diaphragm be flipped over? I had though about just buying the diaphrams. I'm not really mechanically inclined but I can take somthng apart and put It back together. I appreciate any help
 
kimcrwbr1 said:
The fuel pump only has two hoses correct? The hole between the bolt holes is the pulse port from the crankcase, there should be two check valves in the fuel pump take it apart and soak with carb cleaner and blow it out goot with air pressure. Make sure both check valves are working and clean out all the hole good going into the crankcase. Then put it back together and see if it works. could be a piece of crap in a check valve. Replace the fuel lines in the motor!
Click to expand...

ok, I'll try that when I get home and let you know when I get it done. Thanks
 
Burchillb said:
ok, I'll try that when I get home and let you know when I get it done. Thanks
Click to expand...

I've done everything suggested and now it wont even attempt to fire, much less run. I had to screw something up when I put it back together but it was about dark so I'll redo everything when I get off today. Everything was so simple I don't have a clew what I could have done wrong but I did something.
Thanks
 
You may have caused another problem working on the pump. However getting back to basics. Replace the fuel line from the tank to the motor, getting the hose from a marine dealer not auto parts house. I am 65 have seem hoses collapse from the inside, the fuel suction will close an old deteriated hose. Another trick is to cut a V in the pick up tube in the tank if not already done as in some circumstantes the pick up tube will get flat on the bottom of the tank and create a vacuum.
Good luck.
 
Doyle said:
You may have caused another problem working on the pump. However getting back to basics. Replace the fuel line from the tank to the motor, getting the hose from a marine dealer not auto parts house. I am 65 have seem hoses collapse from the inside, the fuel suction will close an old deteriated hose. Another trick is to cut a V in the pick up tube in the tank if not already done as in some circumstantes the pick up tube will get flat on the bottom of the tank and create a vacuum.
Good luck.
Click to expand...

OK, I've done everything everyone has suggested plus I put in a carburetor kit. When I first fired it up, it would only run with the choke out, as soon as you pushed the choke in it would shut off. I played with the adjustment screws and I think it running like it should. I'll know when I put it in the water. Thanks for every ones help and and suggestions.
 
Back
Top