1995 40hp Mariner leaking fuel ... can't figure it out

[fixitrodd]

I have a 40 hp 4cyl Mariner with WMA-10s. I just bought it (a few weeks ago. I'vebeenworkingonit since). I don't know if the carbs leaked before but I did some maintenance like carb cleanup, water pump, seal kit, etc... to make it reliable before putting it on my boat. Both carbs leaked like crazy after I was "done". When I pumped up the bulb gas ca me out the top of the bowl and from inside the carb. I ordered a gasket set and needles from maxrule.com. The top carb sealed up just fine. Bottom carb is the same. Took it off again, checked float height, visually inspected float seat, float is dry inside, i dunked the float in gas for 60sec and used a bright light to inpect if any fuel was inside, tried again. It still leaks when I pump the bulb up and comes right out of the bell of the carbuetor. So, I raised the float (more pressure on needle) and it's the same. The needle seat isn't replaceable (I would have replaced it).

What else can I do?

Am I tackling this the wrong way?

Any help would be very appreciated before I dump it in the lake. ..lol! I just don't know what else to do!

Thank you for your time!!!

-fixitrod-

 

[enginepower]

If the needle isn't sealing to the seat, first, make sure you installed the correct needles. May need to do some research for proper needle size for it. 2nd, you would want to lower the float setting, not raise it if it's over flowing. If the problem is with your seat, you can try a small knurling tool i think it's called. It's what is used to open the inner diameter of a pipe after you cut it. Gentle usage of this tool should all that would be required to remove any debris and get a nice round seat hole. Recheck float level after doing so.

 

[Silvertip]

The only way fuel can get into the carb is through the needle & seat. If it isn't sealing it overflows.

 

[fixitrodd]

When I say raised I mean with the carb upside down. I wasn't clear there. I appreciate the response and the idea of gently rerounding/cleaning the hole. It sounds like I'm on the right track at least. I'm wondering if the needle could be"catching"as well. I'll do some checking tonight. I will update with my results.

Thank you very much! !!

 

[fixitrodd]

I don't have the knurling tool but I played with float height some more. I put a clean gas line on the carb and if I blow in it seems to seal with barely any pressure on the float (bottom off of the carb aND no liquid). When I put it on the boat and pump with fuel, as soon as there's tension on the bulb gas shoots out the pilot jet on the front and comes out the bell. Could it be anything else at all besides the needle? I looked for cracks but don't see any. I know blowing in it isn't the same pressure but it seems to seal so easy,and I barely put the pressure on the bulb makes it shoot out!. I just don't get it. I also checked the needle I just bought, it is correct one.

 

[fixitrodd]

I have tried to renew the needle Seat with some diamond Dremel bit with no luck. I didn't use the dremel, I just rotated them slowly by hand keeping them as centered as possible. There was just brown almost plastic coating. I've seen a lot of pieces of the old fuel lines through this carb project (it had the old Siler lines that the newer ethanol is deteriorating) . I replaced all the fuel lines.

I tested it afterwards by blowing and It seals great from me blowing into it with air.
I even dunked the bottom of the carb in water so the float could float and seal then blew into the carb and it sealed.

When I put it on the engine and pump the bulb not to hard it literally squirts (shoots) out of the pilot jet on the face of the carb and runs out of the bell.

I guess I'll just have to try to find a replacement carb. I'm out of ideas.

Thanks for the responses. I sure thought cleaning/renewing the seat was going to do it. I guess I just don't have the sealing surface perfect enough or there's some crack or something I'm not seeing.

Thanks again everyone.

-fixitrod-

 

[lake429]

I would check to see if you have the problem without the carb on. plug the gas line that goes to carb and pump the bulb up. you may have a problem with your fuel pump if you have a vacuum line from the fuel pump to the side of the intake manifold.

 

[fixitrodd]

I would check to see if you have the problem without the carb on. plug the gas line that goes to carb and pump the bulb up. you may have a problem with your fuel pump if you have a vacuum line from the fuel pump to the side of the intake manifold.

Excellent thought! I just tried it but no fuel came out. So, gas has to be coming through the needle or around the needle seat I guess. I sure was hopeful. Thanks for the suggestion. I'm having a tough time finding a lower WMA-10 carb so any suggestions are very appreciated!

 

[fixitrodd]

***SOLVED***
I wanted to finish this post with my findings. First, thank you to those that responded. You kept me looking at the right things. Bottom line, it was the needles. Here's what I don't understand. The new needles leaked. Brand new, right part number, Identical size and shape, but the tip was grey instead of the original red. Is it harder? Does it matter if the needles sat on the shelf for a long time? What made them not work and the old was work? Any ideas?
Here's the whole battle I went through (shortened up of course).
First, I had one of two carbs leaking (the bottom carb) when I bought the motor. Put new needles in and it still leaked. The needle I took out of it had a worn tip with an obvious ring around it. The new needles leaked on the same carb but not on the other carb (so I thought). In all this I assumed the needle seat was bad, bought a used carb and it was good. I put the new needle in the replacement carb and it leaked. (the top carb has never leaked at this point). I put the red original needle it came with and it sealed right up so I just left it out of frustration but replaced all the gaskets. When I got it on the water the top carb leaked. Now I'm about to throw the motor in the water at this point. I put the original red needle in from the carb that didn't leak when I bought it and it's all good now. That's my story. Finally, got it running, learned a lot about my "new" motor in the process.