84' 115 Carbs Leaking After Rebuild

[RIR]

I just put all 3 carbs back on after cleaning and rebuilding them. New floats and needles and seats. Engine fired right up but now all 3 three are leaking/dripping fuel from the bottom screw plug under the main nozzle. After engine stops they continue to drip fuel. Can I just permatex them? Why are these leaking? Is it a float adjustment issue?

frustratedly yours,

RIR

 

[j_martin]

Re: 84' 115 Carbs Leaking After Rebuild

I just put all 3 carbs back on after cleaning and rebuilding them. New floats and needles and seats. Engine fired right up but now all 3 three are leaking/dripping fuel from the bottom screw plug under the main nozzle. After engine stops they continue to drip fuel. Can I just permatex them? Why are these leaking? Is it a float adjustment issue?

frustratedly yours,

RIR

Float adjustment, or you missed a gasket or bent it with uneven torqueing of screws.

hope it helps
John

 

[sschefer]

Re: 84' 115 Carbs Leaking After Rebuild

I think the bowl vents are on the top so it's probably not float adjustment. My guess is you forgot the gasket on the main jet plug. You would never need permagasket on a carb.

You can go to http://www.crowleymarine.com and search the parts catalog to find the part you left out.

 

[RIR]

Re: 84' 115 Carbs Leaking After Rebuild

I didn't leave out any parts. I actually added some washers on the main jet plugs. Maybe thats the problem? The only thing that had a washer/seal was the needle and seat assembly.

I removed the main jet plugs and main jets (no washers)
I removed the bottom plug (no washers)
I removed the idles screws (no washers)
I removed back draft jets? (no washers)

I didn't removed the welch plugs

The hex shaped main jet plug(s) that face forward at the bottom did not have any gaskets on them. However there were gaskets in the kits that fit so I installed them. This is not where the carbs are leaking from though.

There is another screw type plug underneath these, facing downward (for the venturi tube access)? This is kind of like a big set screw. really no place for a gasket on it as there is head to the screw.

I have another day off tomorrow and will revisit it

 

["G"]

Re: 84' 115 Carbs Leaking After Rebuild

The issue may be that you were not aware of the gaskets that belong on that screw. If there was some gasket material left on the screw or the carb or perhaps you simply inadvertently left the gasket off. I'd be looking at the screw and the embossed area to assure a clean seal area.

Can't think of any other reason short of wrong size screw or cracked carb.

 

[sschefer]

Re: 84' 115 Carbs Leaking After Rebuild

I just checked and there is no gasket on that screw. Are you absolutely sure the fuel is leaking from there or could it be running from the top of the carb and dripping off the screw. That might indicate a float check valve problem.

Just out of curiosity, was the airbox on when you fired it up. A certain amount of fuel can be expected to spit at idle but a bad set of reeds will cause a lot of spit. It doesn't sound like that's the problem but I thought I'd mention it.

 

[RIR]

Re: 84' 115 Carbs Leaking After Rebuild

airbox? I don't have an airbox. This is how I got the boat/motor. These carbs are wide open. no filter, screen or anything. Am I missing an airbox on this thing? Not really spitting fuel at all. just seeping from bottom.

I will double check again in the morning. While running and after engine is shut off, carbs seep/drip fuel. I don't see fuel spitting or running down the carbs anywhere as they are all dry and clean now. Looks like it's seeping out through that bottom plug.

(#25 in crowley diagram)

http://www.crowleymarine.com/mercury_parts/278/10.cfm

Top carb was leaking prior to me taking them off. Now all 3 leak at the same spot.

I must have screwed something up. I will recheck floats in the morning.

guys thanks for you and ideas

will gasoline eat through permatex? what about teflon tape?

 

[verado7]

Re: 84' 115 Carbs Leaking After Rebuild

1 of 2 things .

1 floats incorrectly set -fuel is leaking from carb throat and running down and off the bowl screw -giving the appearance that the bowl screw is at fault

2. there should be a washer -on each side of the bowl 1 inside the bowl that seals the main nozzle and 1 on the outside on the screw .

...of course i am assuming you didnt overtighten the screw and warp the bowl itself - wouldn't be hard though if the inside washer is missing ( they can be stainless or fibre washers ).

 

[sschefer]

Re: 84' 115 Carbs Leaking After Rebuild

airbox? I don't have an airbox. This is how I got the boat/motor. These carbs are wide open. no filter, screen or anything. Am I missing an airbox on this thing? Not really spitting fuel at all. just seeping from bottom.

I will double check again in the morning. While running and after engine is shut off, carbs seep/drip fuel. I don't see fuel spitting or running down the carbs anywhere as they are all dry and clean now. Looks like it's seeping out through that bottom plug.

(#25 in crowley diagram)

http://www.crowleymarine.com/mercury_parts/278/10.cfm

Top carb was leaking prior to me taking them off. Now all 3 leak at the same spot.

I must have screwed something up. I will recheck floats in the morning.

guys thanks for you and ideas

will gasoline eat through permatex? what about teflon tape?

No permatex or teflon tape, use a little locktite blue (medium non-hardening). It might be all you need to seal up the threads.

 

[RIR]

Re: 84' 115 Carbs Leaking After Rebuild

The issue may be that you were not aware of the gaskets that belong on that screw. If there was some gasket material left on the screw or the carb or perhaps you simply inadvertently left the gasket off. I'd be looking at the screw and the embossed area to assure a clean seal area.

Can't think of any other reason short of wrong size screw or cracked carb.

First thing I did when I got the top carb off was to unscrew that plug in question because thats where it seemed to be leaking from. I actually put permatex on it and screwed it back in. Later i decided to just take all 3 carbs off and order 3 kits and floats. So I disassembled and dipped the carbs and all parts over night in chemical cleaner. The only possible type of gasket that I could see being used on this plug screw would be teflon tape or permatex. It has no head and it doesn't bottom out on anything.

 

[RIR]

Re: 84' 115 Carbs Leaking After Rebuild

1 of 2 things .

1 floats incorrectly set -fuel is leaking from carb throat and running down and off the bowl screw -giving the appearance that the bowl screw is at fault

2. there should be a washer -on each side of the bowl 1 inside the bowl that seals the main nozzle and 1 on the outside on the screw .

...of course i am assuming you didnt overtighten the screw and warp the bowl itself - wouldn't be hard though if the inside washer is missing ( they can be stainless or fibre washers ).

1) Floats could very likely be set incorrectly. I am pretty certain the fuel is not leaking from the throat and running down but actually coming from the plug itself. I will check it out again in the morning and see if I can see fuel running down the carb anywhere.

2) Not exactly sure what you mean by each side of bowl but I didn't touch the main nozzle at all. I couldn't figure it out so I left it. I removed the main nozzle plug in question, main jet and plug. None of those had a washer or gasket of any type. I did put a gasket on the main jet plug. The kits did include copper washer for the main jet but I didn't put one on because it didn't have one already. The middle carb had a different size jet than the top and bottom as well.

The bowls could be warped from over tightening, but not from me. Being 25 years old i'm sure they have been off a few times before. I had a hell of a time getting that damn screw out.


thx

 

[RIR]

Re: 84' 115 Carbs Leaking After Rebuild

No permatex or teflon tape, use a little locktite blue (medium non-hardening). It might be all you need to seal up the threads.

I will try the blue loctite. I will also put some gas in the carb bowls and see if they leak before reinstalling.

thanks