Carbs still flooding after rebuild.

David Young

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Jul 12, 2015
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My 1977 70 horsepower boat runs good but the carbs would flood when i pump the bulb 3 or 4 times until firm. To start i would plug in the fuel line to the gas tank without pumping the bulb and turn on the key , then push the key in (choke and prime) until the first hit of the motor. After a couple of cranks without pushing in the key it would start and run great. I figured the carbs needed cleaned out and rebuilt. I rebuilt the carbs and even put in new floats that came with the kit i bought.. I know i adjusted the floats right according to my factory repair manual and many youtube video :). I've tried my other gas tank and it still floods. What else could be making my carbs flood when i pump the bulb? Any help or ideas are welcomed.
 

Vic.S

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My 1977 70 horsepower boat runs good but the carbs would flood when i pump the bulb 3 or 4 times until firm. To start i would plug in the fuel line to the gas tank without pumping the bulb and turn on the key , then push the key in (choke and prime) until the first hit of the motor. After a couple of cranks without pushing in the key it would start and run great. I figured the carbs needed cleaned out and rebuilt. I rebuilt the carbs and even put in new floats that came with the kit i bought.. I know i adjusted the floats right according to my factory repair manual and many youtube video :). I've tried my other gas tank and it still floods. What else could be making my carbs flood when i pump the bulb? Any help or ideas are welcomed.


As Racerone says if the carbs are flooding the float valves are not closing properly ( or are not fitted correctly .... washers fitted??))

Floats sticking ??

needles sticking

dirt on valve seats


If all three are flooding it suggests something you have done incorrectly to all three.
 

David Young

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That's what i thought was happening before i rebuild the carbs. I cleaned everything and put in new needles and floats. The same thing is happening after the rebuild as before. I was very careful with the floats and needles because i was thinking that was the problem with the carbs flooding in the first place. Anymore idea or possibilities?
 

racerone

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Sometimes folks are not willing to accept advice from 40 years experience.--Accept this as fact.--There is a problem with the float valves if leaks occur while squeezing the primer bulb.-----Or if fuel leaks out after cranking with chokes closed it is normal.---Good luck with your motor.
 

jakedaawg

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When you say it floods do you mean that you see fuel leaking out the front of the carbs or the bowl vent? If so racer and others are correct, the float needle and seat when properly installed prevent this from happening.

If by flooding you mean you still cant get the engine to start and have wet plugs there are other causes possible.

Do you see fuel leaking out?
 

David Young

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I believe you all when you say it must be a float needle not closing. Is there an 'easy' way to find out which carb is the one flooding? So i wouldn't have to remove all 3. Thank you all for your help :)
 

jakedaawg

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look and see which one the fuel is coming out of while you pump the bulb. sometimes having the engine tilted some helps.
 

gm280

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I don't doubt you change both the needle and float. But you didn't change the seat. And I can tell you from experience that the seat is the problem. I had a Kohler engine on my lawn mower with a gravity feed carb. And it stated leaking. And Of course I bought a kit and cleaned and rebuilt the carb. But it still leaked. So I bought another kit and rebuilt it again making certain the needle was closing the fuel off when I turned the carb up side down. But it still leaked. And I removed and tried to fix that leak for well over a year. In fact I actually installed a shut-off valve because I couldn't stop it from leaking regardless what I did. I polished the seat and everything I read about fixing the leak. And nothing short of buying a new carb (well over $300 dollars) would fix it. So one day I see a factory repair kit for the seat. Seems others were experiencing the same problems as well. I bought the new seat, installed it, and not a leak since. So buy a new seat and install it and see if that will fix your problem. JMHO!
 

Tim Frank

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Is this a new problem, or did you buy the motor recently and it came like this?
 

David Young

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Jul 12, 2015
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I changed the seats. I just read in the Top Secret section on float adjustment it is "a good idea to have the unhinged (front) of the float just a hair higher than the hinged part of the float to insure the neddle will more likely close off fuel flow". (something like that). I adjusted my floats 'even' all the way around the bowl. I'm going to also do the leak test it told about too. Thank you all.
 

Rapio

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Apr 13, 2013
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Just one more tho't: I have had Bombardie Evinrude carb parts with the correct part number printed on kit but the wrong float for sure and maybe wrong other parts. The float was obviously wrong. On return the dealer wasn't too surprised.
 

David Young

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When i say the carbs are flooding, i mean gas and black stuff from the exhaust is running out the bottom of the motor near the propeller. :)


Got it all figured out with the help from you all. Pumped the bulb hard with the front carbs cover off and the motor tilted up. For over an hour, no gas coming out of the front of either carb (3 of them). I started thinking, i must be flooding them with the 'primer choke' when i try to start it for the first time of the day. I thought when you push the key in and hear the 'click' sound, all it was doing was closing the choke butterfly on the carbs. I just learned a few days ago it is also squirting a little fuel at the same time. I was the one flooding my motor by priming it too much. :(


Now, for the first starting of the day i turn the key on, push the key in and let the motor crank until it hits (hit means it runs for a second or two then dies) or starts. After it does the first hit and doesn't start i don't push the key in to primer choke it because it will flood. It will most of the time start on the 2nd or 3rd try. I never crank my motor for more than 5 or 6 seconds at a time.



Thank all of you so much for your help. Everything seems to be working perfect for now :)
 

racerone

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???????---But , but the 77 models did not come with the primer injector valve.----It just has choke plates that only work when motor is turning over.-----Just another example of mis-information and it is difficult to help those who do not clearly state what is going on !!!----No fuel is squirted in on a 77 model, unless of course there is a newer powerhead installed or someone has added the fuel primer unit !!!!!
 
Last edited:

Fed

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Gas and black stuff can be pretty normal running on a flusher.
 

trebot

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Jul 7, 2004
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102
I had same problem. Rebuilt carb again ("63 40 hp). [Make sure you replace the O ring gasket between float bowl pick up tube and bottom of float bowl. Motor will never be right without that gasket in place (personal experience)].
Pumped bulb till hard, crank over; gas poured out front of carb. Disconnected fuel line to tank and cranked till fuel stopped pouring out front of carb. Hook up fuel line, Fired right up, no flooding.
Since then, I only squeeze bulb if change fuel tank(1 squeeze). Motor always starts and runs fine (even Cold) just using choke.
 
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