Merc carb/float question for the experts

[sillvechevy]

Hi,
My problem is this- I have an 1980-1981 merc 150, that leaks fuel from the middle and bottom carbs. I recently floated the boat (1971 mako 19), and idled from ramp to my mooring. Fuel proceeded to leak the whole time, and I did not get boat out of 1500 rpm (no wake zone). Not just a drizzle of fuel, but not a steady flow also. If I plugged my single center scupper, the accumulation would fill the recess. This is a recurring problem from last season. My mechanic ran the boat one week ago in the yard, with no leaking noted)I just had carbs rebuilt again (2 weeks ago), new tank put in (with new fuel so ethanol shouldnt be an issue-yet) The mechanic states that the float for the carbs may be bad, causing inadequate seals. My questions are this:
1)Any ideas why fuel is leaking?
2)Any ideas where to get the floats for this particular merc
Part number:
13957827 (original part)
13956024 (replacement)
13957623 (replacement)
13957267 (replacement).
My mechanic and I have tried Sierra, and Mr Gasket, these parts are no longer available, and if any one knows where to get them, I would GREATLY appreciate it.
Thank you, and looking forward to hearing thoughts on current problem.
Ron

[Raceman]

Early Mercs are notorious for needle and seat leaks and have NO tolerance for excess fuel pressure. I assume that since you didn't mention it that it hasn't been converted to an electric pump. I've never seen a bad float cause the carb to flood on a Merc, so the chance of having "bad floats" in two carbs seems remote. ('course I haven't ever run fuel in one with ethenol added either). I don't know what the latest on the needle seat thing is, but way back then there was an aftermarket set available that would absolutely stop it and I think Merc started using that design later. (it's been a long time and my memory is foggy) Of course setting the float level WRONG would cause the carbs to flood also.

Is your mechanic experienced with V6 Mercs?

[rjdubiel]

if it isnt the needles and seats, then the floats are full of gas. they are made of some kind of foam and after time they start to break down and then they dont "float" as well as they should in the bowls. this makes the carb think it needs more gas in the bowl and just keeps it flowing in and then out the front of the carb. i have been looking for some time for new ones/used in good condition for my 1978 v6. good luck finding them, start calling every merc dealer in the US and maybe you will find some left over stock at one of them. the last time i read about this here, cant remember who it was, but he had to get 3 or 4 floats and he got them from 2 or 3 different places!!

hope its just he needle and seats.

good luck again
RJ

[j_martin]

Like RJ says. The early WH's had foam floats and when gasohol came out, they all sank. The hard plastic floats live forever, so nobody, including Mercury or any aftermarket outfit bothers to make them. There is no market for them.

Used is just as good as new. If that's what you need, buy a set of 135 or 150 carbs from a later motor of eBay, just for the floats.

hope it helps
John

[sillvechevy]

I agree, I need a new set of floats, but if I get a set of used carbs, will the problem reoccur due to the new gasohol.
Ron

[MERC SCREAMER]

If you remove the float bowls, make sure that there is clearance between the float and the bowl hounsing. Some of the earlier floats were just a tad too large (or swelled overtime) and would strike the edge of the bowl housing, thereby limiting the last bit of travel required for the needle to close off the seat. I had this problem last year on one of my BPs. I found some different floats in the "junk pile" that had better clearance and solved the problem.

Just a thought....

[rjdubiel]

is there any option to update to a carb off a newer merc where you can get new parts for it. i am willing to bet i need new floats in my motor,

[j_martin]

I agree, I need a new set of floats, but if I get a set of used carbs, will the problem reoccur due to the new gasohol.
Ron

Gasohol sinks the old foam floats. Since about 1988 or so, they've been using a hard plastic blonde colored float that's unsinkable. That's why I suggested you buy a set of anything WH (135 horse up) from a later engine to get floats.

hope it helps
John

[Steve2ManyBoats]

I had this problem on my 2.0 175. The bottom two carbs would leak badly. Turns out that the original foam floats were not sinking, they were swelling and the front of the floats would sometimes hang up on the inside of the float bowl. Six new white plastic floats cured the problem and my carbs never drip (other than choking) and my motor idles at a steady 700 RPM all day long trolling for stripers.

Go for the new white plastic floats. It's cheap and solves the problem once and for all.

Steve2ManyBoats.

[rjdubiel]

I had this problem on my 2.0 175. The bottom two carbs would leak badly. Turns out that the original foam floats were not sinking, they were swelling and the front of the floats would sometimes hang up on the inside of the float bowl. Six new white plastic floats cured the problem and my carbs never drip (other than choking) and my motor idles at a steady 700 RPM all day long trolling for stripers.

Go for the new white plastic floats. It's cheap and solves the problem once and for all.

Steve2ManyBoats.

what year is your 2.0 175? and where did you get the new style floats?

[sillvechevy]

I'd love to get the new white/yellow plastic floats.......if I could find them. Any leads?
Ron

[Steve2ManyBoats]

It's a 79 2.0 175. The PN for the white plastic float is 1395-9267, at least that's what the Quicksilver parts bag says. Got 'em about a year ago from a local Merc stealer without incident.

Steve2ManyBoats.

[sillvechevy]

I tracked down and got 6 new white floats, and am happy to say my leaking carbs leak no more (for now). Thanks for all your help guys.
Ron