Carb dissasembly on a Mercury 1150...

I have not cleaned my carbs in a few years and now that I am trying to I realize why I put it off so long - it's a real pain disassembling them. Here are the steps as best I can figure out and I am stuck on the last one and could use some advice. Feel free to chime in if I am doing something inefficiently along the way. What makes this so tedious is that there are a lot of parts to remove before you can remove the carbs.

1) remove top cover to "flywheel"
2) remove starter.
3) remove gas lines.
4) remove distributor cap - this gives you a chance to clean it, which mine had lots of "green sand/dirt/rust" in it.
4) pull float valve tops so you can get at the main carb bolts
5) remove linkage
6) loosen the top of the distributor assembly so you can toggle it out in order to remove the top carb.

Now this last step is where I am stuck because I can't figure out how to get at the back nut on this assembly - it seems like I will need a really skinny 3/8 wrench, that is a really thin head on the wrench, to loosen this nut.

Any suggestions on how to loosen this nut, or any of the steps I've taken, would be appreciated.


I am tempted to machine down either the end of the carb housing or the distributor assembly so that this won't be an issue in the future, but I am afraid of compromising the parts.

Incidently, the same "green sand/dirt/rust" was in the float bowls as was in the didstributor cap - any ideas on what I am looking at. This is a salt water boat.

Re: Carb dissasembly on a Mercury 1150...

Not all the distributor Mercs were exactly the same, however, I was always able to remove the top carb w/o removing or loosening the distributor. It took a bit of wiggling however. I would recommend you leave the distributor alone. I also don't recommend machining down anything. Worst comes to worse, you may be able to remove the top carb fitting that is pushed by the distributor. The screws may come out of the carb throttle shaft, to butterfly, allowing you to pull out the throttle shaft. I don't recommend that as the parts may be brittle after all these years.

Re: Carb dissasembly on a Mercury 1150...

Chris1956 said:

Not all the distributor Mercs were exactly the same, however, I was always able to remove the top carb w/o removing or loosening the distributor. It took a bit of wiggling however. I would recommend you leave the distributor alone. I also don't recommend machining down anything. Worst comes to worse, you may be able to remove the top carb fitting that is pushed by the distributor. The screws may come out of the carb throttle shaft, to butterfly, allowing you to pull out the throttle shaft. I don't recommend that as the parts may be brittle after all these years.

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Hmm,.. Believe me I have tried to wiggle and am worried I will strip off the threads of the bolt. I'll give it another go. I am pretty sure I loosened the distributor the last time I did this and remeber it was a royal pain but can't remember how I did it.

Have I got the rest of the sequence right Chris? Any more suggestions on cleaning these carbs or a thread the details it?


Incidentally, I adjusted the shift cable and could get the reverse to work but it still slipped under load. I then had a supposed Mercury mechanic give it a go with no improvement - "he's not good with people" and won't talk to me, however. I've got another place to try down in Waterford, CT (Outboard Exchange) - they will rebuild the lower unit for $500 or put in a rebuilt one for $700 (maybe $800 - I can't remember for sure).

Re: Carb dissasembly on a Mercury 1150...

DVTO2 said:

Hmm,.. Believe me I have tried to wiggle and am worried I will strip off the threads of the bolt. I'll give it another go. I am pretty sure I loosened the distributor the last time I did this and remeber it was a royal pain but can't remember how I did it.

Have I got the rest of the sequence right Chris? Any more suggestions on cleaning these carbs or a thread the details it?


Incidentally, I adjusted the shift cable and could get the reverse to work but it still slipped under load. I then had a supposed Mercury mechanic give it a go with no improvement - "he's not good with people" and won't talk to me, however. I've got another place to try down in Waterford, CT (Outboard Exchange) - they will rebuild the lower unit for $500 or put in a rebuilt one for $700 (maybe $800 - I can't remember for sure).

Click to expand...

OK. I finally figured out I can get in there with an ignition wrench. I don't actually have to remove the distributor, just loosen it and wiggle it away from the the carb while I am wiggling the carb off the motor.

Other suggestions for cleaning these or link detailing this would still be appreciated.

Re: Carb dissasembly on a Mercury 1150...

Sure, Disassemble the carb until you can blow out each passage with compressed air or carb cleaner spray. It is not necessary to remove all the jets, but usually the brass plugs need to come out. Soak the carb in carb cleaner and then blast out all passages and jets. Reassemble with new gaskets, float, inlet needle and seat. Blow out idle passages in carb throat.

Re: Carb dissasembly on a Mercury 1150...

Chris1956 said:

Sure, Disassemble the carb until you can blow out each passage with compressed air or carb cleaner spray. It is not necessary to remove all the jets, but usually the brass plugs need to come out. Soak the carb in carb cleaner and then blast out all passages and jets. Reassemble with new gaskets, float, inlet needle and seat. Blow out idle passages in carb throat.

Click to expand...

So I am looking for a gasket kit for this carb, a 1972 1150 serial 3369246. There are a couple out there, two on iboats and two on **********. the bottom of the carb says mercarb 1399-3682, with a 1 1/4 in the middle.

It looks like the following carb:



I need the float bowl gaskets, filter screens, and a brass nut gasket (I think part 30 on the image). ********** does not sell either the filter screens or the brass nut gasket, except as possibly on one of the kits. Not sure about iboats kits either.

Re: Carb dissasembly on a Mercury 1150...

i could use seats for the filter screens as well.

Re: Carb dissasembly on a Mercury 1150...

Gee, that is a common carb. I would think all the parts you need will be avail in multiple places on the web, iBoats and at a Merc dealer. The crowleymarine web site and ebasicpower web site should have all you need. Replace float and inlet needle and seat.