Flooding carb on 1997 25 HP (Force) Gamefisher.

[mercman2]

Im working on a 25 hp Gamefisher with a flooding problem. I have rebuilt the carb with a new needle and gaskets. (seat is non replaceable). Seat had some of the plating gone around the top surface that you can see...so I figured it was possible the seat was bad. I new this carb was NLA but was lucky enough to find a new old stock one on a marinas back shelf. Didn't fix the problem. Carb does the same thing. Just pours gas down the intake. Have had both carbs apart many times to check needles and float heights. Even tried pinning the needle with a lean float adjustment to no avail. So have since rebuilt fuel pump and still having the same problem. Any ideas? Feedback is greatly appreciated.

 

[gm280]

Usually you can tell if the needle and seat are working by flipping the carb upside down and try blowing air in the inlet. If the air goes through flip it back over and try again. The air should not go through when upside down but easily flow through right side up. If you can hear air flowing through while upside down, it will never work but flood the engine. If you can't blow air when upside down, you have some other problem with gas getting in. Maybe the choke system needs attention, And I don't actually know the proper float setting but usually when the float is parallel with the carb body fuel bowl it is right... JMHO!

 

[jerryjerry05]

Post pics of the old needle and the new one you put in.
Some have a rubber tip some are solid. The kits sometimes have a different size needle(compare)
The carbs that use the solid needle will have a small o-ring in the seat.
Ethanol has destroyed a lot of rubber and maybe the seat's bad?
Post some pics.

 

[mercman2]

Thanks gm and Jerry. I have the old carb off now gonna check that one first. The needles are rubber tipped and and the seat is non replaceable. I have compared the kit needle to the needle that was in the new old stock carb...same needle. I had built this old carb several years ago with no problems other than where someone else had been into it but it wasnt damage that effected the performance of the motor. Just of as late the motor sat for a spell and we all know what happens...carb got dirty. problem has popped up since the fresh build and continues to the new carb. Im baffled unless the seat is bad in the new carb as well.

 

[mercman2]

Aight so I just did the ole blow test on the old carb. There appears to be nothing wrong with it. Can't blow thru inlet and thats with the old needle in it as well. Plastic floats are intact and not taking in gas. The gas comes strait up the venturi...with a pretty good flow. It will flood with the primer bulb or the pressure of the fuel pump.

 

[gm280]

Aight so I just did the ole blow test on the old carb. There appears to be nothing wrong with it. Can't blow thru inlet and thats with the old needle in it as well. Plastic floats are intact and not taking in gas. The gas comes strait up the venturi...with a pretty good flow. It will flood with the primer bulb or the pressure of the fuel pump.

If this was just one carb doing that I would certain tell you that the seat is your problem. Had that actually happen to me. But two carbs points to too much fuel pressure in my mind. Maybe you need to check the fuel pressure from the fuel pump. It shouldn't be very much, usually around 3 - 5 PSI. Much more then that, you could be overriding the needle force and flooding... IDK :noidea: However, whatever you do find as your answer, please post it back on here for us to learn about and understand... Thanks :thumb:

 

[mercman2]

Yes its a single carb. I managed to find another that is new old stock. thats why I keep refering to 2 carbs. Both are acting the same way and I have rebuilt the no longer available fuel pump as well. Carb was doing this before the pump build and continue to do it after. One of the mysteries of life I guess. I will let you know if I find a solution.Thank you for your help gm. Gonna take a closer look at the pump I guess.

 

[jerryjerry05]

The floats. New?
Pics?
Check the diaphragm.
If the pumps valves are not in right that might be the problem.
The pump put together right?

The NLA pump is just a Mercury pump.
A good parts guy/girl can get the one you need.
The rebuild kit. 820748A 1 Can be bought at any Mercury dealer.

 

[mercman2]

Happy Father's Day Jerry. The float is not new in the old carb, is in the new carb. Both floats are in good shape and not taking on fuel. I did build the pump and there were issues with one of the lil red neoprene valves, but the flooding occurred before and after the build. Can't see any cracks in the pump body itself. I'm gonna take it apart again today. I thought the pump might have been put together wrong too but according to the parts breakdown everything is correct.

 

[mercman2]

No Title

Sorry Jerry had to figure out how to resize my photo's so the website would let me download them.