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What does a man have to do to get a Tillotson fuel pump inlet to quit leaking?

hotrod53

Contributing Member
I had no leaks, I pulled the carbs to clean them and I had a hard time getting the plastic inlet piece off of the carb, it was stuck. Once I reassembled them, I literally had to reassemble the inlet piece 15 times to get it to stop leaking. I bought a rebuild kit with all new gaskets after that and now it leaks again! I have had these things apart another 15 times and they still leak. It appears to be coming from around the blue plastic inlet. I have been assembling them and ball pumping the line.. maybe it won't leak when its running but obviously it would every time I started out.

The old gaskets were deformed with a step, obviously the new ones are still flat. I can tighten these things till I'm afraid they will break and it still leaks! The tollerances are real tight where the inlet sits on the fuel pump but you really can't screw it up. I have also tried swapping the inlets between the carbs and the leak is always the bottom carb. Nothing looks deformed, cracked or damaged.

Any suggestions?

Here is a parts breakdown with the troublesom parts:

http://i154.photobucket.com/albums/s276/hotrod53/Boat Album/MercCarb.jpg
 
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Hah! Had the same problem. What's causing it is that the screw is bottoming out before it clamps the plastic piece tight enough to seal. THe solution is a flat washer or two on the screw.

Jeff
 
My rebuild kit came with some odd and end washers that I assumed went to another kind of carb. One of the washers I guessed was for under that screw although it didn't fit exactly right and the center of the inlet piece has a groove which this washer didn't fit in. When I installed a washer, it leaked worse!

The fuel pump has a center tower in the casting where the screw goes, my leak appears to be from around the outer edge and I don't think that it is bottoming out. I can continue to eeek it down a little at a time and at no time did it ever bottom out. It's been on and off so many times that the head is getting destroyed.

I'm wondering if when the pump is actually run, it it will suck it in and seal it or cause the gasket to start to form to the contour?
 
The blue plastic piece is now too big in it's diameter.----------------------Try shaving a bit of the outside diameter and it will seal !
 
It's "too big" because it has splayed outward (warped) over time. That makes the bolt too long to clamp it--the threads bottom out. Sand the plastic piece until it fits again, then put enough flat washers under the bolt head to squeeze it tight again. I've done several of these and it's a guaranteed fix.

Jeff
 
This sounds like my problem, so I want to take a little off from around the edge diameter so that it doesn't hit the ridge that guides it into place, right? This makes perfect sense because it kind or wants to snap into place as it is now, like it doesn't want to fit the hole. I'm sure that I'm not bottoming out, I can continue to tighten it and the head still turns. Maybe it is hanging up around the edge, and while the bolt is trying to center it, its not possible to center because it is hitting the ridge around the edge. I could even just for good measure, cut a little off of the bolt, it is plenty long enough. I'm also suprised that there is no seal or fiber fiwasher around the screw.

I'll give it a try again this afternoon .... just when I thought that I could go at least one day without reeking from fuel...LOL
 
I though maybe there should be because of the groove. It's not there, it doesn't show on the parts list, and it wasn't in the rebuild kit. I'll have to make a trip to the hardware store.
 
UPDATE: I flat sanded the gasket surface on the blue plastic part and took a cut off around the outside. I reasembled, and of course it leaked, I repeated the proceedure another 2 times with little success. I then went to the hardware store and bought plastic washers for around the screw, replaced the screws, and took another cut from around the edge. At that point I would say that I am 98% fixed! I see an infrequent drip and I'm not even sure where it came from. I'm thinking that I should buy new blue plastic pieces.

I still see bubbles in my fuel lines, I have replaced everything, ball pump, all fuel line, connector on the engine, connector on the fuel tank, and the fuel tank. I used that yellow translucent fuel line only where the carbs TEE so that I can see the fuel. It seems to run OK, maybe the bubbles are not anything to worry about. One guy told me to use black fuel line so I couldn't see them..LOL.
 
I got back from my shake down run and I had fuel everywhere inside the cowl! I found and purchased replacement blue plastic inlet pieces and it appears to have finally resolved the problem. Years of use and exposed to fuel must have caused the piece to deform. The new ones are more concave and they fit the round inlet on the carb casting much better.
 
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