Potential Mercury 135 hp fuel leak

[fletchermerc1996]

Hey guys,

So I'm back, hoping for some more advice!!

I have a 1994 Mercury 135 2.0 litre V6 outboard.

It generally runs very well, with no problems. I've had some work done on it, since we brought it 6 months ago.

Prior to me buying the boat, the engine had had quite a bit or work done. Since we have had it, I've had the impeller and housing changed, T-stats changed, and carbs removed, cleaned and rebalanced.

I recently had the engine checked by a mechanic, and he reported that the number two carb was leaking fuel. The problem was corrected and now, when we prime the bulb, it generally gets hard quickly, where as before it didn't.

So, we had the boat out for the week, and had no problems. There was no immediate sign of a fuel leak, until we tilted the engine up, and we would get a small amount of fuel leaking out the back of the engine, into the transom area. This was the same when we got the boat out the water. We removed the cowling, and there was a small pool of fuel at the back of the engine.

I'm assuming this isn't normal and an obvious fire risk. Anyone have any ideas of what might be causing this, if it's not the carbs leaking? Hopefully you can give me some advice or point me in the right direction!!

Cheers

 

[Dukedog]

Re: Potential Mercury 135 hp fuel leak

Check ALL tha bleed line hoses/fittings for cracks and/or holes or just not hooked up. These will olny leak when tha motor is running....................

 

[fletchermerc1996]

Re: Potential Mercury 135 hp fuel leak

I haven't noticed any problems when the engine is running, although I haven't had the cowling off when it's running to check, but there doesn't appear to be any visible fuel leaking from the engine or fuel in the water. I've only really observed it when it's shut down and the engine tilted up. Can I assume that under no circumstances should fuel leak out like this?

 

[Paul DuLaney]

Re: Potential Mercury 135 hp fuel leak

I had a 135 merc on a Searay seville and the style of carbs on it were the back draft so when you tilted all the way up to load and put the transom saver on it would leak a little out the front of the carbs thus run down to the bottom of the cowling. When I trim the motor down in the full trim position the would cause any residue to go to the back. To remedy this I'd wipe out just below the carbs if I did a lot of idling with the motor trimed up ofter loading and id made a world of difference.

 

[al9981]

Re: Potential Mercury 135 hp fuel leak

I have a 75hp 2 stroke that does the same. After research, I think all or most mercury outboards leak the gas left over from the carburetors when tilted all the way up and then down. I dont use the support bracket on the outboard (I am planning on buying one soon), so I tilt the outboard all the way up when towing and when I get home, I drop the motor down. And the gas will leak out of the carburetors and into the motor pan and then out of the motor area onto the transom area.

 

[fletchermerc1996]

Re: Potential Mercury 135 hp fuel leak

If there was a fuel leak from the carbs, would this be obvious when priming the bulb? I know before, that when priming the bulb, it would never really get that hard. When the mechanic checked over it, he said that this was because the number 2 carb was leaking fuel and when priming the bulb, fuel was leaking out of this carb. Since this has been rectified, the bulb generally gets hard quickly. So can I assume that if I get pressure from the bulb, that this suggests that fuel isn't leaking directly from the carbs? Thanks again!

 

[j_martin]

Re: Potential Mercury 135 hp fuel leak

If there was a fuel leak from the carbs, would this be obvious when priming the bulb? I know before, that when priming the bulb, it would never really get that hard. When the mechanic checked over it, he said that this was because the number 2 carb was leaking fuel and when priming the bulb, fuel was leaking out of this carb. Since this has been rectified, the bulb generally gets hard quickly. So can I assume that if I get pressure from the bulb, that this suggests that fuel isn't leaking directly from the carbs? Thanks again!

It's not unusual to spill a little fuel from the float bowls when you tilt the engine all the way up.

Run it on the muffs with the cowl off and look for leaks. Like he said, bleed lines will not leak unless the engine is running. When they do, they make a mess.

hope it helps
john