'66 merc 110 carb question

[rustvyper]

I've cleaned & painted & got my grandad's old 66 110 restored as good as new. Put her in the lake today & she ran like a champ for a good while. Then it suddenly died. Cracked the hood & I see a empty screw hole in the carberator which is leaking gas. I find the offending nut & put it back. However, when I screw it all the way in the motor won't start. When I unscrew it some it will start, however the screw eventually vibrates out & the motor dies. Obviously this is not supposed to happen. Someone please help me out with this, how do I adjust the mixture so I can crank this screw down like it should be! Thanks.

 

[IBFishing]

Re: '66 merc 110 carb question

What fell out? Was it a nut or a screw with a smooth taper that goes down to a point (idle mixture screw)? It sounds like it is your idle mixture screw. If it is your mixture screw, it is supposed to have a spring around it (or in the hole) to keep pressure applied so that it doesn't unscrew with vibration.

 

[rustvyper]

Re: '66 merc 110 carb question

no, it wasn't my idle mixture screw...I know where that one is.<br />This one is at the very bottom of the carb. Right below the chamber w/the float. If you take it out, you can see there is another screw farther in. <br />I took the boat out again today & it ran fine for the first 2 stops then it would not run again w/out lossening that damn nut (it is a brass nut w/a hex head). The motor starts up w/out a prob when I let it out halfway, but it's anyone's guess before it shakes out again, & it leakes fuel the whole time.

 

[dajohnson53]

Re: '66 merc 110 carb question

rustvyper- go to <br /> merc part look up <br /><br />and find your motor in their parts search - they have exploded views of carburetors, and you could tell us which part is involved. You'll need your serial number - or if not, look at the carbs for various earlier Merc 110's until you see a carb that looks familiar.<br /><br />As a point of reference, my 1974 merc 110 is sn 39XXXXX, so your 66 will be several slots above that in the list.

 

[rustvyper]

Re: '66 merc 110 carb question

Thanks! That's an awesome website...just what I need. In reference to your question it's part #33, or what they call the "SCREW, PLUG-MAIN FUEL JET CHANNEL". This is the nut that has to be half out to run...

 

[dajohnson53]

Re: '66 merc 110 carb question

Of course, I'm too ignorant to actually HELP you with your problem, but now I'm thinking someone can! Good luck, have fun.

 

[IBFishing]

Re: '66 merc 110 carb question

I do not understand why you have to have this plug screw part-way unscrewed for it to run. This is just a plug to access the main jet.<br /><br />Possible cause could be that the float level is set incorrectly (or bad needle and seat) allowing too much fuel to get through the carb. This could be causing it not to run (flooding). Assuming this is the case, haveing that plug unscrewed would allow less gas to get through due to some of it leaking out. This is just a guess. I personally would check your float level.

 

[soup87]

Re: '66 merc 110 carb question

I have a quick comment. could it be possable that the plug is suposed to have a fiber washer on it, and if it doesn't have one the plug screws in too far and interfears with the main jet?<br /><br />I'm no expert but I think it is something to start on. Or you could put on a washer or two.<br /><br />Steve

 

[rustvyper]

Re: '66 merc 110 carb question

hmmm...I'm guessing it's the float. When I had it on the lake today, when it quit working it was because the 30 year old float has sprung a leak and filled with gas. I'll get a new one, but I bet you are right & that solves my problem...Thanks!