merc 1150 carb problems (again)

[JeffM]

Hi boaters, After receiving your advice, I had my 1975 Merc 1150 in this spring for a carb job (all 3) and the motor has been purring like a kitten ever since. Until this weekend.<br /><br />Saturday she's running great. Skiing all day. Never a problem. Sunday morning I go to start it up and it pretty much fires immediately, but stalls and sputters. It keeps doing this, even with the idle lever at full throttle. I found if I dropped it into gear and gave it gas it would spring to life, but then stall when I backed off. I smelled gas so I took the cover off and gas was pretty much flowing out of the top carb. I was told before that this was a float problem and I figured the carb job would have fixed it. Could I have done anything to make this happen again? What happens if you hold the choke too long or oversqueeze the prime bulb? I may have done either or both of these. Speaking of which, the prime bulb never seems to get hard. It gets harder after the first 2 squeezes, but never really gets totally hard. You can hear a squirting noise coming from the engine while squeezing the prime bulb as well.<br /><br />The problem fixed itself eventually, but I'd like to know what I did so I can avoid doing it again. Thanks.

 

[12Footer]

Re: merc 1150 carb problems (again)

Old fuel is the bane of 2cycle engines, so check this first. The fuel must be less than 1 year old, and then,only if StaBill or other fuel stabilizer has been added.<br />It does sound like the float stuck, or the needle valve it pushes up,is not seating. Try this;<br />Have someone pump the primer,not hard, but enough to keep the gas going to the carbs.<br />At the same time your helper is doing this, take a scredriver handle,and thump the bowl gently,to see if you can get the fuel to quit overflowing. If you can, it's only varnish or trash holding the needle open,and you may have allready 'fixed' it by unsticking it.<br />If not, dissasembly is required.

 

[aeronutt29]

Re: merc 1150 carb problems (again)

I'm a big fan of total disassembly. You can do this in an hour if you work slow and it guarantees that any gunk will be dislodged. Use the Gumout liberally! While you have it open, be sure to check the filter very carefully for tears or poor seals. Another problem I've encountered a few times is a hole in the float that makes it sink. If that's the problem, it never will close the valve!

 

[JeffM]

Re: merc 1150 carb problems (again)

Thanks guys, I'll be trying that this weekend. The gas did eventually stop streaming out when dropped the throttle, maybe the vibration seated the needle. Hopefully it doesn't happen again, but if it does I'll try your advice.<br />Cheers!